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HBR Disruptive Technologies - Catching the Wave

Disruptive Technologies

Catching the Wave

by Joseph L. Bower and Clayton M. Christensen

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Disruptive Technologies: Catching the Wave

Disruptive Technologies

Catching the Wave

The Idea in Brief

The Idea in Practice

C O P Y R I G H T ? 2000 H A R V A R

D B U S I N

E S S S C H O O L P U B L I S H I N G C O R P O R A T I O N . A L L R I G H T S R E S E R V E D .

Goodyear, Xerox, Bucyrus-Erie, Digital. Leading companies all—yet they all failed to stay at the top of their industries when technologies or markets changed radically. That’s disturbing enough, but the reason for the failure is downright alarming. The very processes that successful, well-managed companies use to serve the rap-idly growing needs of their current custom-ers can leave them highly vulnerable when market-changing technologies appear.When a technology that has the potential for revolutionizing an industry emerges, established companies typically see it as unattractive: it’s not something their main-stream customers want, and its projected profit margins aren’t sufficient to cover big-company cost structures. As a result, the new technology tends to get ignored in favor of what’s currently popular with the best customers. But then another com-pany steps in to bring the innovation to a new market. Once the disruptive technol-ogy becomes established there, smaller-scale innovations rapidly raise the technol-ogy’s performance on attributes that mainstream customers value.

What happens next is akin to the rapid, final moves leading to checkmate. The new technology invades the established market. By the time the established sup-plier—with its high overhead and profit margin requirements—wakes up and smells the coffee, its competitive disad-vantage is insurmountable.

At issue here is a key distinction:

?Sustaining innovation maintains a steady rate of product improvement.?Disruptive innovation often sacrifices per-formance along dimensions that are impor-tant to current customers and offers a very different package of attributes that are not (yet) valued by those customers. At the same time, the new attributes can open up entirely new markets. For example, Sony’s early transistor radios sacrificed sound fidel-ity, but they created a new market for small, portable radios.Staying focused on your main customers can work so well that you overlook disruptive technologies. The consequences can be far more disastrous than a missed opportunity. Case in point: not one of the independent hard-disk drive companies that existed in 1976 is still around today.

To prevent disruptive technologies from slip-ping through their fingers, established organi-zations must learn how to identify and nur-ture innovations on a more modest scale—so that small orders are meaningful, ill-defined markets have time to mature, and overhead is low enough to permit early profits. Here’s a four-step guide:

1. Determine whether the technology is dis-ruptive or sustaining. Ask the technical folks—they’re more attuned than marketing and financial managers to which technologies have the potential to revolutionize the market.

2. Define the strategic significance of the disruptive technology. Your best customers are the last people to ask about this—sustain-ing technologies are what they care about.

3. Locate the initial market for the disruptive technology. If the market doesn’t yet exist, conventional market research won’t give you the information you need. So create it instead, by experimenting rapidly, iteratively, and inex-pensively—with both the product and the market.

4. House the disruptive technology in an independent entity. For a disruptive tech-nology to thrive, it can’t be required to com-pete with established products for company resources.

Disruptive Technologies

Catching the Wave

by Joseph L. Bower and Clayton M. Christensen

C O P Y R I G H T ? 1994 H A R V A R

D B U S I N

E S S S C H O O L P U B L I S H I N G C O R P O R A T I O N . A L L R I G H T S R E S E R V E D .

One of the most consistent patterns in busi-ness is the failure of leading companies to stay at the top of their industries when technolo-gies or markets change. Goodyear and Fire-stone entered the radial-tire market quite late.Xerox let Canon create the small-copier mar-ket. Bucyrus-Erie allowed Caterpillar and Deere to take over the mechanical excavator market. Sears gave way to Wal-Mart.

The pattern of failure has been especially striking in the computer industry. IBM domi-nated the mainframe market but missed by years the emergence of minicomputers, which were technologically much simpler than main-frames. Digital Equipment dominated the mini-computer market with innovations like its VAX architecture but missed the personal-computer market almost completely. Apple Computer led the world of personal computing and estab-lished the standard for user-friendly computing but lagged ?ve years behind the leaders in bringing its portable computer to market.

Why is it that companies like these invest ag-gressively—and successfully—in the technolo-gies necessary to retain their current custom-ers but then fail to make certain other technological investments that customers of the future will demand? Undoubtedly, bureau-cracy, arrogance, tired executive blood, poor planning, and short-term investment horizons have all played a role. But a more fundamental reason lies at the heart of the paradox: leading companies succumb to one of the most popu-lar, and valuable, management dogmas. They stay close to their customers.

Although most managers like to think they are in control, customers wield extraordinary power in directing a company’s investments.Before managers decide to launch a technol-ogy, develop a product, build a plant, or estab-lish new channels of distribution, they must look to their customers ?rst: Do their cus-tomers want it? How big will the market be?Will the investment be pro?table? The more astutely managers ask and answer

these questions, the more completely their invest-ments will be aligned with the needs of their customers.

This is the way a well-managed company should operate. Right? But what happens when customers reject a new technology, prod-uct concept, or way of doing business because it does not address their needs as effectively as a company’s current approach? The large pho-tocopying centers that represented the core of Xerox’s customer base at ?rst had no use for small, slow tabletop copiers. The excavation contractors that had relied on Bucyrus-Erie’s big-bucket steam- and diesel-powered cable shovels didn’t want hydraulic excavators be-cause initially they were small and weak. IBM’s large commercial, government, and industrial customers saw no immediate use for minicom-puters. In each instance, companies listened to their customers, gave them the product perfor-mance they were looking for, and, in the end, were hurt by the very technologies their cus-tomers led them to ignore.

We have seen this pattern repeatedly in an ongoing study of leading companies in a vari-ety of industries that have confronted techno-logical change. The research shows that most well-managed, established companies are con-sistently ahead of their industries in develop-ing and commercializing new technologies—from incremental improvements to radically new approaches—as long as those technolo-gies address the next-generation performance needs of their customers. However, these same companies are rarely in the forefront of com-mercializing new technologies that don’t ini-tially meet the needs of mainstream customers and appeal only to small or emerging markets. Using the rational, analytical investment processes that most well-managed companies have developed, it is nearly impossible to build a cogent case for diverting resources from known customer needs in established markets to markets and customers that seem insigni?-cant or do not yet exist. After all, meeting the needs of established customers and fending off competitors takes all the resources a company has, and then some. In well-managed compa-nies, the processes used to identify customers’needs, forecast technological trends, assess pro?tability, allocate resources across compet-ing proposals for investment, and take new products to market are focused—for all the right reasons—on current customers and mar-kets. These processes are designed to weed out proposed products and technologies that do not address customers’ needs.

In fact, the processes and incentives that companies use to keep focused on their main customers work so well that they blind those companies to important new technologies in emerging markets. Many companies have learned the hard way the perils of ignoring new technologies that do not initially meet the needs of mainstream customers. For example, although personal computers did not meet the requirements of mainstream minicomputer users in the early 1980s, the computing power of the desktop machines improved at a much faster rate than minicomputer users’ demands for computing power did. As a result, personal computers caught up with the computing needs of many of the customers of Wang, Prime, Nix-dorf, Data General, and Digital Equipment. Today they are performance-competitive with minicomputers in many applications. For the minicomputer makers, keeping close to main-stream customers and ignoring what were ini-tially low-performance desktop technologies used by seemingly insigni?cant customers in emerging markets was a rational decision—but one that proved disastrous.

The technological changes that damage es-tablished companies are usually not radically new or dif?cult from a technological point of view. They do, however, have two important characteristics: First, they typically present a different package of performance attributes—ones that, at least at the outset, are not valued by existing customers. Second, the perfor-mance attributes that existing customers do value improve at such a rapid rate that the new technology can later invade those established markets. Only at this point will mainstream customers want the technology. Unfortunately for the established suppliers, by then it is often too late: the pioneers of the new technology dominate the market.

It follows, then, that senior executives must ?rst be able to spot the technologies that seem to fall into this category. Next, to commercial-ize and develop the new technologies, manag-ers must protect them from the processes and incentives that are geared to serving estab-lished customers. And the only way to protect them is to create organizations that are com-pletely independent from the mainstream business.

No industry demonstrates the danger of staying too close to customers more dramati-cally than the hard-disk-drive industry. Be-

Joseph L. Bower is the Donald Kirk David Professor of Business Adminis-tration at the Harvard Business School in Boston, Massachusetts. Clayton M. Christensen, an assistant professor at the Harvard Business School, specializ-es in managing the commercialization of advanced technology.

tween 1976 and 1992, disk-drive performance improved at a stunning rate: the physical size of a 100-megabyte (MB) system shrank from 5,400 to 8 cubic inches, and the cost per MB fell from $560 to $5. Technological change, of course, drove these breathtaking achieve-ments. About half of the improvement came from a host of radical advances that were criti-cal to continued improvements in disk-drive performance; the other half came from incre-mental advances.

The pattern in the disk-drive industry has been repeated in many other industries: the leading, established companies have consis-tently led the industry in developing and adopt-ing new technologies that their customers de-manded—even when those technologies required completely different technological competencies and manufacturing capabilities from the ones the companies had. In spite of this aggressive technological posture, no single disk-drive manufacturer has been able to domi-nate the industry for more than a few years. A series of companies have entered the business and risen to prominence, only to be toppled by newcomers who pursued technologies that at ?rst did not meet the needs of mainstream cus-tomers. As a result, not one of the independent disk-drive companies that existed in 1976 sur-vives today.

To explain the differences in the impact of certain kinds of technological innovations on a given industry, the concept of performance trajectories—the rate at which the perfor-mance of a product has improved, and is ex-pected to improve, over time—can be helpful. Almost every industry has a critical perfor-mance trajectory. In mechanical excavators, the critical trajectory is the annual improve-ment in cubic yards of earth moved per minute. In photocopiers, an important perfor-mance trajectory is improvement in number of copies per minute. In disk drives, one crucial measure of performance is storage capacity, which has advanced 50% each year on average for a given size of drive.

Different types of technological innovations affect performance trajectories in different ways. On the one hand, sustaining technologies tend to maintain a rate of improvement; that is, they give customers something more or bet-ter in the attributes they already value. For ex-ample, thin-?lm components in disk drives, which replaced conventional ferrite heads and oxide disks between 1982 and 1990, enabled in-formation to be recorded more densely on disks. Engineers had been pushing the limits of the performance they could wring from ferrite heads and oxide disks, but the drives employ-ing these technologies seemed to have reached the natural limits of an S curve. At that point, new thin-?lm technologies emerged that re-stored—or sustained—the historical trajectory of performance improvement.

On the other hand, disruptive technologies introduce a very different package of attributes from the one mainstream customers histori-cally value, and they often perform far worse along one or two dimensions that are particu-larly important to those customers. As a rule, mainstream customers are unwilling to use a disruptive product in applications they know and understand. At ?rst, then, disruptive tech-nologies tend to be used and valued only in new markets or new applications; in fact, they generally make possible the emergence of new markets. For example, Sony’s early transistor radios sacri?ced sound ?delity but created a market for portable radios by offering a new and different package of attributes—small size, light weight, and portability.

In the history of the hard-disk-drive industry, the leaders stumbled at each point of disrup-tive technological change: when the diameter of disk drives shrank from the original 14 inches to 8 inches, then to 5.25 inches, and ?-nally to 3.5 inches. Each of these new architec-tures initially offered the market substantially less storage capacity than the typical user in the established market required. For example, the 8-inch drive offered 20 MB when it was in-troduced, while the primary market for disk drives at that time—mainframes—required 200 MB on average. Not surprisingly, the lead-ing computer manufacturers rejected the 8-inch architecture at ?rst. As a result, their sup-pliers, whose mainstream products consisted of 14-inch drives with more than 200 MB of ca-pacity, did not pursue the disruptive products aggressively. The pattern was repeated when the 5.25-inch and 3.5-inch drives emerged: es-tablished computer makers rejected the drives as inadequate, and, in turn, their disk-drive suppliers ignored them as well.

But while they offered less storage capacity, the disruptive architectures created other im-portant attributes—internal power supplies and smaller size (8-inch drives); still smaller

Managers must beware of ignoring new technologies that don’t initially meet the needs of their mainstream customers.

size and low-cost stepper motors (5.25-inch drives); and ruggedness, light weight, and low-power consumption (3.5-inch drives). From the late 1970s to the mid-1980s, the availability of the three drives made possible the develop-ment of new markets for minicomputers, desk-top PCs, and portable computers, respectively.Although the smaller drives represented dis-ruptive technological change, each was tech-nologically straightforward. In fact, there were engineers at many leading companies who championed the new technologies and built working prototypes with bootlegged resources before management gave a formal go-ahead.Still, the leading companies could not move the products through their organizations and into the market in a timely way. Each time a disruptive technology emerged, between one-half and two-thirds of the established manufac-turers failed to introduce models employing

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the new architecture—in stark contrast to their timely launches of critical sustaining technolo-gies. Those companies that ?nally did launch new models typically lagged behind entrant companies by two years—eons in an industry whose products’ life cycles are often two years. Three waves of entrant companies led these revolutions; they ?rst captured the new mar-kets and then dethroned the leading compa-nies in the mainstream markets.

How could technologies that were initially in-ferior and useful only to new markets eventu-ally threaten leading companies in established markets? Once the disruptive architectures be-came established in their new markets, sustain-ing innovations raised each architecture’s per-formance along steep trajectories—so steep that the performance available from each architec-ture soon satis?ed the needs of customers in the established markets. For example, the 5.25-inch drive, whose initial 5 MB of capacity in 1980 was only a fraction of the capacity that the minicom-puter market needed, became fully performance-competitive in the minicomputer market by 1986 and in the mainframe market by 1991. (See the graph “How Disk-Drive Performance Met Market Needs.”)

A company’s revenue and cost structures play a critical role in the way it evaluates pro-posed technological innovations. Generally, disruptive technologies look ?nancially unat-tractive to established companies. The poten-tial revenues from the discernible markets are small, and it is often dif?cult to project how big the markets for the technology will be over the long term. As a result, managers typically conclude that the technology cannot make a meaningful contribution to corporate growth and, therefore, that it is not worth the manage-ment effort required to develop it. In addition, established companies have often installed higher cost structures to serve sustaining tech-nologies than those required by disruptive technologies. As a result, managers typically see themselves as having two choices when de-ciding whether to pursue disruptive technolo-gies. One is to go downmarket and accept the lower pro?t margins of the emerging markets that the disruptive technologies will initially serve. The other is to go upmarket with sustain-ing technologies and enter market segments whose pro?t margins are alluringly high. (For example, the margins of IBM’s mainframes are still higher than those of PCs). Any rational re-source-allocation process in companies serving established markets will choose going upmar-ket rather than going down.

Managers of companies that have champi-oned disruptive technologies in emerging mar-kets look at the world quite differently. With-out the high cost structures of their established counterparts, these companies ?nd the emerg-ing markets appealing. Once the companies have secured a foothold in the markets and im-proved the performance of their technologies, the established markets above them, served by high-cost suppliers, look appetizing. When they do attack, the entrant companies ?nd the established players to be easy and unprepared opponents because the opponents have been looking upmarket themselves, discounting the threat from below.

It is tempting to stop at this point and con-clude that a valuable lesson has been learned: managers can avoid missing the next wave by paying careful attention to potentially disrup-tive technologies that do not meet current cus-tomers’ needs. But recognizing the pattern and ?guring out how to break it are two different things. Although entrants invaded established markets with new technologies three times in succession, none of the established leaders in the disk-drive industry seemed to learn from the experiences of those that fell before them. Management myopia or lack of foresight can-not explain these failures. The problem is that managers keep doing what has worked in the past: serving the rapidly growing needs of their current customers. The processes that success-ful, well-managed companies have developed to allocate resources among proposed invest-ments are incapable of funneling resources into programs that current customers explic-itly don’t want and whose pro?t margins seem unattractive.

Managing the development of new technol-ogy is tightly linked to a company’s investment processes. Most strategic proposals—to add ca-pacity or to develop new products or pro-cesses—take shape at the lower levels of orga-nizations in engineering groups or project teams. Companies then use analytical plan-ning and budgeting systems to select from among the candidates competing for funds. Proposals to create new businesses in emerg-ing markets are particularly challenging to as-sess because they depend on notoriously unre-liable estimates of market size. Because

None of the established leaders in the disk-drive industry learned from the experiences of those that fell before them.

managers are evaluated on their ability to place the right bets, it is not surprising that in well-managed companies, mid- and top-level managers back projects in which the market seems assured. By staying close to lead custom-ers, as they have been trained to do, managers focus resources on ful?lling the requirements of those reliable customers that can be served pro?tably. Risk is reduced—and careers are safeguarded—by giving known customers what they want.

Seagate Technology’s experience illustrates the consequences of relying on such resource-allocation processes to evaluate disruptive tech-nologies. By almost-any measure, Seagate, based in Scotts Valley, California, was one of the most successful and aggressively managed companies in the history of the microelectron-ics industry: from its inception in 1980, Seagate’s revenues had grown to more than $700 million by 1986. It had pioneered 5.25-inch hard-disk drives and was the main supplier of them to IBM and IBM-compatible personal-computer manufacturers. The company was the leading manufacturer of 5.25-inch drives at the time the disruptive 3.5-inch drives emerged in the mid-1980s.

Engineers at Seagate were the second in the industry to develop working prototypes of 3.5-inch drives. By early 1985, they had made more than 80 such models with a low level of com-pany funding. The engineers forwarded the new models to key marketing executives, and the trade press reported that Seagate was ac-tively developing 3.5-inch drives. But Seagate’s principal customers—IBM and other manufac-turers of AT-class personal computers—showed no interest in the new drives. They wanted to incorporate 40-MB and 60-MB drives in their next-generation models, and Seagate’s early 3.5-inch prototypes packed only 10 MB. In response, Seagate’s marketing execu-tives lowered their sales forecasts for the new disk drives.

Manufacturing and ?nancial executives at the company pointed out another drawback to the 3.5-inch drives. According to their analysis, the new drives would never be competitive with the 5.25-inch architecture on a cost-per-megabyte basis—an important metric that Seagate’s customers used to evaluate disk drives. Given Seagate’s cost structure, margins on the higher-capacity 5.25-inch models there-fore promised to be much higher than those on the smaller products.

Senior managers quite rationally decided that the 3.5-inch drive would not provide the sales volume and pro?t margins that Seagate needed from a new product. A former Seagate marketing executive recalled, “We needed a new model that could become the next ST412 [a 5.25-inch drive generating more than $300 million in annual sales, which was nearing the end of its life cycle]. At the time, the entire market for 3.5-inch drives was less than $50 million. The 3.5-inch drive just didn’t ?t the bill—for sales or pro?ts.”

The shelving of the 3.5-inch drive was not a signal that Seagate was complacent about in-novation. Seagate subsequently introduced new models of 5.25-inch drives at an acceler-ated rate and, in so doing, introduced an im-pressive array of sustaining technological im-provements, even though introducing them rendered a signi?cant portion of its manufac-turing capacity obsolete.

While Seagate’s attention was glued to the personal-computer market, former employees of Seagate and other 5.25-inch drive makers, who had become frustrated by their employ-ers’ delays in launching 3.5-inch drives, founded a new company, Conner Peripherals. Conner focused on selling its 3.5-inch drives to companies in emerging markets for portable computers and small-footprint desktop prod-ucts (PCs that take up a smaller amount of space on a desk). Conner’s primary customer was Compaq Computer, a customer that Seagate had never served. Seagate’s own pros-perity, coupled with Conner’s focus on custom-ers who valued different disk-drive attributes (ruggedness, physical volume, and weight), minimized the threat Seagate saw in Conner and its 3.5-inch drives.

From its beachhead in the emerging market for portable computers, however, Conner im-proved the storage capacity of its drives by 50% per year. By the end of 1987, 3.5-inch drives packed the capacity demanded in the main-stream personal-computer market. At this point, Seagate executives took their company’s 3.5-inch drive off the shelf, introducing it to the market as a defensive response to the attack of entrant companies like Conner and Quantum Corporation, the other pioneer of 3.5-inch drives. But it was too late.

By then, Seagate faced strong competition. For a while, the company was able to defend

Small, hungry organizations are good at agilely changing product and market strategies.

its existing market by selling 3.5-inch drives to its established customer base—manufacturers and resellers of full-size personal computers. In fact, a large proportion of its 3.5-inch products continued to be shipped in frames that en-abled its customers to mount the drives in computers designed to accommodate 5.25-inch drives. But, in the end, Seagate could only struggle to become a second-tier supplier in the new portable-computer market.

In contrast, Conner and Quantum built a dom-inant position in the new portable-computer market and then used their scale and experi-ence base in designing and manufacturing 3.5-inch products to drive Seagate from the per-sonal-computer market. In their 1994 ?scal years, the combined revenues of Conner and Quantum exceeded $5 billion.

Seagate’s poor timing typi?es the responses of many established companies to the emer-gence of disruptive technologies. Seagate was willing to enter the market for 3.5-inch drives only when it had become large enough to sat-isfy the company’s ?nancial requirements—that is, only when existing customers wanted the new technology. Seagate has survived through its savvy acquisition of Control Data Corporation’s disk-drive business in 1990. With CDC’s technology base and Seagate’s volume-manufacturing expertise, the company has be-come a powerful player in the business of sup-plying large-capacity drives for high-end com-puters. Nonetheless, Seagate has been reduced to a shadow of its former self in the personal-computer market.

It should come as no surprise that few com-panies, when confronted with disruptive tech-nologies, have been able to overcome the handicaps of size or success. But it can be done. There is a method to spotting and cultivating disruptive technologies.

Determine whether the technology is disrup-tive or sustaining.The ?rst step is to decide which of the myriad technologies on the hori-zon are disruptive and, of those, which are real threats. Most companies have well-conceived processes for identifying and tracking the progress of potentially sustaining technologies, because they are important to serving and pro-tecting current customers. But few have sys-tematic processes in place to identify and track potentially disruptive technologies.

One approach to identifying disruptive tech-nologies is to examine internal disagreements over the development of new products or tech-nologies. Who supports the project and who doesn’t? Marketing and ?nancial managers, because of their managerial and ?nancial in-centives, will rarely support a disruptive tech-nology. On the other hand, technical personnel with outstanding track records will often per-sist in arguing that a new market for the tech-nology will emerge—even in the face of oppo-sition from key customers and marketing and ?nancial staff. Disagreement between the two groups often signals a disruptive technology that top-level managers should explore.

De?ne the strategic signi?cance of the dis-ruptive technology.The next step is to ask the right people the right questions about the stra-tegic importance of the disruptive technology. Disruptive technologies tend to stall early in strategic reviews because managers either ask the wrong questions or ask the wrong people the right questions. For example, established companies have regular procedures for asking mainstream customers—especially the impor-tant accounts where new ideas are actually tested—to assess the value of innovative prod-ucts. Generally, these customers are selected because they are the ones striving the hardest to stay ahead of their competitors in pushing the performance of their products. Hence these customers are most likely to demand the high-est performance from their suppliers. For this reason, lead customers are reliably accurate when it comes to assessing the potential of sus-taining technologies, but they are reliably in ac-curate when it comes to assessing the potential of disruptive technologies. They are the wrong people to ask.

A simple graph plotting product perfor-mance as it is de?ned in mainstream markets on the vertical axis and time on the horizon-tal axis can help managers identify both the right questions and the right people to ask. First, draw a line depicting the level of perfor-mance and the trajectory of performance im-provement that customers have historically enjoyed and are likely to expect in the future. Then locate the estimated initial performance level of the new technology. If the technology is disruptive, the point will lie far below the performance demanded by current custom-ers. (See the graph “How to Assess Disruptive Technologies.”)

What is the likely slope of performance im-provement of the disruptive technology com-

Seagate paid the price for allowing start-ups to lead the way into emerging markets.

pared with the slope of performance improve-ment demanded by existing markets? If knowledgeable technologists believe the new technology might progress faster than the mar-ket’s demand for performance improvement, then that technology, which does not meet customers’ needs today, may very well address them tomorrow. The new technology, there-fore, is strategically critical.

Instead of taking this approach, most man-agers ask the wrong questions. They compare the anticipated rate of performance improve-ment of the new technology with that of the established technology. If the new technology has the potential to surpass the established one, the reasoning goes, they should get busy developing it.

Pretty simple. But this sort of comparison, while valid for sustaining technologies, misses the central strategic issue in assessing poten-tially disruptive technologies. Many of the dis-ruptive technologies we studied never sur-passed the capability of the old technology. It is the trajectory of the disruptive technology compared with that of the market that is signif-icant. For example, the reason the mainframe-computer market is shrinking is not that per-sonal computers outperform mainframes but because personal computers networked with a ?le server meet the computing and data-storage needs of many organizations effec-tively. Main-frame-computer makers are reel-ing not because the performance of personal-computing technology surpassed the perfor-mance of mainframe technology but because it intersected with the performance demanded by the established market.

Consider the graph again. If technologists believe that the new technology will progress at the same rate as the market’s demand for performance improvement, the disruptive technology may be slower to invade estab-lished markets. Recall that Seagate had tar-geted personal computing, where demand for hard-disk capacity per computer was growing at 30% per year. Because the capacity of 3.5-inch drives improved at a much faster rate, leading 3.5-inch-drive makers were able to force Seagate out of the market. However, two other 5.25-inch-drive makers, Maxtor and Micropolis, had targeted the engineering-workstation market, in which demand for hard-disk capacity was insatiable. In that mar-ket, the trajectory of capacity demanded was essentially parallel to the trajectory of capacity improvement that technologists could supply in the 3.5-inch architecture. As a result, enter-ing the 3.5-inch-drive business was strategically less critical for those companies than it was for Seagate.

Locate the initial market for the disruptive technology. Once managers have determined that a new technology is disruptive and strategi-cally critical, the next step is to locate the initial markets for that technology. Market research, the tool that managers have traditionally relied on, is seldom helpful: at the point a company needs to make a strategic commitment to a dis-ruptive technology, no concrete market exists. When Edwin Land asked Polaroid’s market re-searchers to assess the potential sales of his new camera, they concluded that Polaroid would sell a mere 100,000 cameras over the product’s life-time; few people they interviewed could imag-ine the uses of instant photography.

Because disruptive technologies frequently signal the emergence of new markets or mar-ket segments, managers must create informa-tion about such markets—who the customers will be, which dimensions of product perfor-mance will matter most to which customers, what the right price points will be. Managers can create this kind of information only by ex-perimenting rapidly, iteratively, and inexpen-sively with both the product and the market. For established companies to undertake such experiments is very dif?cult. The resource-allocation processes that are critical to pro?t-

ability and competitiveness will not—and should not—direct resources to markets in which sales will be relatively small. How, then, can an established company probe a market for a disruptive technology? Let start-ups—ei-ther ones the company funds or others with no connection to the company—conduct the ex-periments. Small, hungry organizations are good at placing economical bets, rolling with the punches, and agilely changing product and market strategies in response to feedback from initial forays into the market.

Consider Apple Computer in its start-up days. The company’s original product, the Apple I, was a ?op when it was launched in 1977. But Apple had not placed a huge bet on the product and had gotten at least something into the hands of early users quickly. The com-pany learned a lot from the Apple I about the new technology and about what customers wanted and did not want. Just as important, a group of customers learned about what they did and did not want from personal computers. Armed with this information, Apple launched the Apple II quite successfully.

Many companies could have learned the same valuable lessons by watching Apple closely. In fact, some companies pursue an ex-plicit strategy of being second to invent—allow-ing small pioneers to lead the way into un-charted market territory. For instance, IBM let Apple, Commodore, and Tandy de?ne the per-sonal computer. It then aggressively entered the market and built a considerable personal-computer business.

But IBM’s relative success in entering a new market late is the exception, not the rule. All too often, successful companies hold the per-formance of small-market pioneers to the ?-nancial standards they apply to their own per-formance. In an attempt to ensure that they are using their resources well, companies ex-plicitly or implicitly set relatively high thresh-olds for the size of the markets they should consider entering. This approach sentences them to making late entries into markets al-ready ?lled with powerful players.

For example, when the 3.5-inch drive emerged, Seagate needed a $300-million-a-year product to replace its mature ?agship 5.25-inch model, the ST412, and the 3.5-inch market wasn’t large enough. Over the next two years, when the trade press asked when Seagate would introduce its 3.5-inch drive,company executives consistently responded that there was no market yet. There actually was a market, and it was growing rapidly. The signals that Seagate was picking up about the market, in?uenced as they were by customers who didn’t want 3.5-inch drives, were mislead-ing. When Seagate ?nally introduced its 3.5-inch drive in 1987, more than $750 million in 3.5-inch drives had already been sold. Informa-tion about the market’s size had been widely available throughout the industry. But it wasn’t compelling enough to shift the focus of Seagate’s managers. They continued to look at the new market through the eyes of their cur-rent customers and in the context of their cur-rent ?nancial structure.

The posture of today’s leading disk-drive makers toward the newest disruptive technol-ogy, 1.8-inch drives, is eerily familiar. Each of the industry leaders has designed one or more models of the tiny drives, and the models are sitting on shelves. Their capacity is too low to be used in notebook computers, and no one yet knows where the initial market for 1.8-inch drives will be. Fax machines, printers, and au-tomobile dashboard mapping systems are all candidates. “There just isn’t a market,”com-plained one industry executive. “We’ve got the product, and the sales force can take orders for it. But there are no orders because nobody needs it. It just sits there.”This executive has not considered the fact that his sales force has no incentive to sell the 1.8-inch drives instead of the higher-margin products it sells to higher-volume customers. And while the 1.8-inch drive is sitting on the shelf at his company and others, last year more than $50 million worth of 1.8-inch drives were sold, almost all by start-ups. This year, the market will be an estimated $150 million.

To avoid allowing small, pioneering compa-nies to dominate new markets, executives must personally monitor the available intelli-gence on the progress of pioneering companies through monthly meetings with technologists, academics, venture capitalists, and other non-traditional sources of information. They cannot rely on the company’s traditional channels for gauging markets because those channels were not designed for that purpose.

Place responsibility for building a disruptive-technology business in an independent organi-zation. The strategy of forming small teams into skunk-works projects to isolate them from

Every company that has tried to manage mainstream and disruptive businesses within a single organization failed.

the sti?ing demands of mainstream organiza-tions is widely known but poorly understood. For example, isolating a team of engineers so that it can develop a radically new sustaining technology just because that technology is rad-ically different is a fundamental misapplication of the skunk-works approach. Managing out of context is also unnecessary in the unusual event that a disruptive technology is more ?-nancially attractive than existing products. Consider Intel’s transition from dynamic ran-dom access memory (DRAM) chips to micro-processors. Intel’s early microprocessor busi-ness had a higher gross margin than that of its DRAM business; in other words, Intel’s normal resource-allocation process naturally provided the new business with the resources it needed.1 Creating a separate organization is necessary only when the disruptive technology has a lower pro?t margin than the mainstream busi-ness and must serve the unique needs of a new set of customers. CDC, for example, success-fully created a remote organization to com-mercialize its 5.25-inch drive. Through 1980, CDC was the dominant independent disk-drive supplier due to its expertise in making 14-inch drives for mainframe-computer makers. When the 8-inch drive emerged, CDC launched a late development effort, but its engineers were re-peatedly pulled off the project to solve prob-lems for the more pro?table, higher-priority 14-inch projects targeted at the company’s most important customers. As a result, CDC was three years late in launching its ?rst 8-inch product and never captured more than 5% of that market.

When the 5.25-inch generation arrived, CDC decided that it would face the new challenge more strategically. The company assigned a small group of engineers and marketers in Oklahoma City, Oklahoma, far from the main-stream organization’s customers, the task of developing and commercializing a competi-tive 5.25-inch product. “We needed to launch it in an environment in which everybody got ex-cited about a $50,000 order,” one executive re-called. “In Minneapolis, you needed a $1 mil-lion order to turn anyone’s head.”CDC never regained the 70% share it had once enjoyed in the market for mainframe disk drives, but its Oklahoma City operation secured a pro?table 20% of the high-performance 5.25-inch market. Had Apple created a similar organization to develop its Newton personal digital assistant (PDA), those who have pronounced it a ?op might have deemed it a success. In launching the product, Apple made the mistake of acting as if it were dealing with an established mar-ket. Apple managers went into the PDA project assuming that it had to make a signi?-cant contribution to corporate growth. Accord-ingly, they researched customer desires exhaus-tively and then bet huge sums launching the Newton. Had Apple made a more modest technological and ?nancial bet and entrusted the Newton to an organization the size that Apple itself was when it launched the Apple I, the outcome might have been different. The Newton might have been seen more broadly as a solid step forward in the quest to discover what customers really want. In fact, many more Newtons than Apple I models were sold within a year of their introduction.

Keep the disruptive organization indepen-dent. Established companies can only domi-nate emerging markets by creating small orga-nizations of the sort CDC created in Oklahoma City. But what should they do when the emerg-ing market becomes large and established? Most managers assume that once a spin-off has become commercially viable in a new mar-ket, it should be integrated into the main-stream organization. They reason that the ?xed costs associated with engineering, manu-facturing, sales, and distribution activities can be shared across a broader group of customers and products.

This approach might work with sustaining technologies; however, with disruptive tech-nologies, folding the spin-off into the main-stream organization can be disastrous. When the independent and mainstream organiza-tions are folded together in order to share re-sources, debilitating arguments inevitably arise over which groups get what resources and whether or when to cannibalize established products. In the history of the disk-drive indus-try, every company that has tried to manage main-stream and disruptive businesses within a single organization failed.

No matter the industry, a corporation con-sists of business units with ?nite life spans: the technological and market bases of any business will eventually disappear. Disruptive technolo-gies are part of that cycle. Companies that un-derstand this process can create new busi-nesses to replace the ones that must inevitably die. To do so, companies must give managers

In order that it may live, a corporation must be willing to see business units die.

of disruptive innovation free rein to realize the technology’s full potential—even if it means ultimately killing the mainstream business. For the corporation to live, it must be willing to see business units die. If the corporation doesn’t kill them off itself, competitors will.

The key to prospering at points of disruptive change is not simply to take more risks, invest for the long term, or ?ght bureaucracy. The key is to manage strategically important dis-ruptive technologies in an organizational con-text where small orders create energy, where fast low-cost forays into ill-de?ned markets are possible, and where overhead is low enough to permit pro?t even in emerging markets. Managers of established companies can mas-ter disruptive technologies with extraordinary success. But when they seek to develop and launch a disruptive technology that is rejected by important customers within the context of the mainstream business’s ?nancial demands, they fail—not because they make the wrong decisions, but because they make the right de-cisions for circumstances that are about to be-come history.

1. Robert A. Burgelman, “Fading Memories: A Process The-ory of Strategic Business Exit in Dynamic Environments,”Administrative Science Quarterly 39 (1994), pp. 24–56. Reprint 95103

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Disruptive Technologies

Catching the Wave

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跟我学Java Swing GUI组件技术及应用实例——JTable表格组件及应用实例

1.1跟我学Java Swing GUI组件技术及应用实例——JTable表格组件及应用实例 1.1.1表格控件JTable 1、JTable表格控件的主要功能 JTable顾名思义就是一个将数据以表格显示的组件，它提供以行和列的方式来显示数据，并且可以拖动列。如下示图为应用JTable表格控件所创建出的数据表格。 JTable的数据选项不仅仅是可以显示字符串，还可以显示Checkbox选择框、下拉列表框或者图片等内容。如下为Sun 公司的Swing 教程中的TableDialogEditoDemo 应用程序的执行结果示图，在该示例的数据表格中显示Checkbox选择框、下拉列表框和图片等内容。

2、JTable类的API功能说明（1）JTable类的API功能说明如下示图为JDK API文档中对JTable类的API功能说明的相关信息。如果需要对数据表格中的表头数据列和数据单元格中的数据列进行定制，则需要通过继承封装表头数据列JTableHeader类或者继承封装数据列的TableColumn类。如下为JTableHeader类和TableColumn类的功能说明。（2）表头数据列JTableHeader类的功能说明

（3）数据列TableColumn类的功能说明 TableColumn 类封装表示JTable中数据列的所有属性，如宽度、大小可调整性、最小和最大宽度。 3、JTable表格控件中的数据可以以多种不同的方式被选中（1）选中某一数据行

（2）选中连续的多行数据行

（3）选中不连续的多行数据行

4、JTable类的构造函数定义可以通过JTable(Object[][] rowData, Object[] columnNames)形式的构造方法创建出数据表格组件，该JTable组件将用来显示一个二维数组rowData 中的值（它是一个行数组），其列名称为columnNames所代表的数组。JTable类的其它形式的构造函数定义如下：

JAVA基础测试及答案

第一单元Java基础知识测样班级___________姓名：_____________得分：_____________ 一、选择题（每题2分，共40分） 1、下面哪项可以得到数组元素的个数，java中定义数组名为abc，（B） A、abc.length() B、abc.length C、len(abc) D、ubound(abc) 2、构造方法何时被调用(B) A.类定义时 B.创建对象时 C.调用对象方法时 D.使用对象的变量时 3、下列语句片段int a=10,b=4,c=20,d=6;System.out.println(a++*b+c*--d);的结果为 (C) A.144 B.28 C.140 D.不能执行 4、下面哪个修饰符修饰的方法只能被本类中的其他方法使用（C） A、protected B、static C、private D、public 5、编译并运行下述程序段的结果是：(A)。 public class Test{ public static void main(String argv[]){ int[]count=new int[4]; System.out.println(count[4]);}} A．编译时错误B．运行时错误C．输出0D．输出null 6、在java的一个异常处理中，哪个语句块可以有多个（A） A、catch B、finally C、try D、throws 7、若在某一个类定义中定义有如下的方法： final void aFinalFunction(); 则该方法属于（C）。 A．本地方法B．静态方法C．最终方法D．抽象方法 9、类Test1定义如下： 1)public class Test1{ 2)public float aMethod(float a,float b){} 3) 4)}将以下哪种方法插入行3是不合法的。（B） A、public float aMethod（float a,float b,float c）{} B、public float aMethod（float c,float d）{} C、public int aMethod（int a,int b）{} D、private float aMethod（int a,int b,int c）{}

现在分词用法总结

现在分词一、基础知识：现在分词（也叫动名词）：表示主动和进行。基本形式：doing 否定式：not doing 被动式：being done 完成式：having done 二、具体用法： 1.动名词作主语和宾语：（1）把一个动词变成-ing形式可以当做名词来用，表示一种经常性、习惯性的动作，可在句中充当主语和宾语。 eg: Working with you is a pleasure. I like reading in my free time. （2）可以用it做形式主语或形式宾语放在前面，再用动名词做真正的主语或宾语放在后面，这种用法常用于以下句式： ①It is/was no use/good doing sth. 做某事是没用的/没有好处的。 eg: It’s no use begging for his mercy. It’s no good smoking too much. ②It is/was a waster of time doing sth. 做某事是浪费时间的。 eg: It is a waste of time copying others’ homework. ③It is/was worth doing sth. 做某事是值得的。 eg: It was worth making the effort. ④There is/was no sense in doing sth. 做某事是没有道理的/意义的。 eg: There is no sense in arguing with your wife. ⑤There is/was no point (in) doing sth. 做某事是没用的/无意义的。 eg: There is no point in getting angry. ⑥There is no shame in doing sth. 做某事是不丢脸的。 eg: There is no shame in saying sorry to your friends. ⑦There is no telling…无法预言会… eg: There is no telling what will happen. ※注意：动名词作主语时，其前可用名词所有格和形容词性物主代词修饰，即one’s doing sth.作主语。 eg: Tom’s being late again made his teacher angry. My going to Beijing University is my parents’ biggest dream. （3）动名词作宾语分为两种情况：动名词后的宾语和介词后的宾语 ①有些动词后只能接动名词作宾语，常见的有： avoid, advise, allow, admit, appreciate, consider, deny, enjoy, keep, finish, suggest, dislike, delay, risk, escape, imagine, mind, miss, permit, practice, fancy, can’t help, be busy, give up, can’t stand, feel like等。 eg: You must avoid being hurt when crossing the road. ②有些动词后即可接动名词也可接不定式作宾语，常见的有： A: start, begin, intend, attempt, continue等后接doing和to do无区别。 B: like, love, prefer, hate等后接doing和to do略有区别，后接doing侧重经常习惯性的行为，后接to do侧重具体的某一次行为。 eg: I like swimming in summer but today I like to see a film at home

java异常试题

异常作业一．填空题填空题 1．一个try语句块后必须跟（ catch ）语句块，（ finally ）语句块可以没有2．自定义异常类必须继承（）类及其子类 3．异常处理机制允许根据具体的情况选择在何处处理异常，可以在（）捕获并处理，也可以用throws子句把他交给（）处理二．选择题二．选择题 1. finally语句块中的代码（） A．总是被执行 B．当try语句块后面没有catch时，finally中的代码才会执行 C．异常发生时才执行 D．异常没有发生时才被执行 2. 抛出异常应该使用的关键字是（） A．throw B．catch C．finally D．throws 3. 自定义异常类时，可以继承的类是（） A．Error B．Applet C．Exception及其子类 D．AssertionError 4. 在异常处理中，将可能抛出异常的方法放在（）语句块中 A．throws B．catch C．try D．finally 5. 对于try{……}catch子句的排列方式，下列正确的一项是（） A．子类异常在前，父类异常在后 B．父类异常在前，子类异常在后 C．只能有子类异常 D．父类异常与子类异常不能同时出现 6. 使用catch(Exception e)的好处是（） A．只会捕获个别类型的异常 B．捕获try语句块中产生的所有类型的异常 C．忽略一些异常 D．执行一些程序三．简答题三．简答题 1. try/catch/finally如何使用？ 2. throw/throws有什么联系和区别？ 3. 如何自定义异常类？ 4. 谈谈final、finally的区别和作用 5. 如果try{}里有一个return语句，那么紧跟在这个try后的finally{}里的代码会不会被执行？

初中英语现在分词用法总结

初中英语现在分词用法总结一、基础知识：现在分词（也叫动名词）：表示主动和进行。基本形式：doing 否定式：not doing 被动式：being done 完成式：having done 二、具体用法： 1.动名词作主语和宾语：（1）把一个动词变成-ing形式可以当做名词来用，表示一种经常性、习惯性的动作，可在句中充当主语和宾语。 eg: Working with you is a pleasure. I like reading in my free time. （2）可以用it做形式主语或形式宾语放在前面，再用动名词做真正的主语或宾语放在后面，这种用法常用于以下句式： ① It is/was no use/good doing sth. 做某事是没用的/没有好处的。 eg: It’s no use begging for his mercy. It’s no good smoking too much. ② It is/was a waster of time doing sth. 做某事是浪费时间的。eg: It is a waste of time copying others’ homework. ③ It is/was worth doing sth. 做某事是值得的。 eg: It was worth making the effort. ④ There is/was no sense in doing sth. 做某事是没有道理的/

意义的。 eg: There is no sense in arguing with your wife. ⑤ There is/was no point (in) doing sth. 做某事是没用的/ 无意义的。 eg: There is no point in getting angry. ⑥ There is no shame in doing sth. 做某事是不丢脸的。 eg: There is no shame in saying sorry to your friends. ⑦ There is no telling…无法预言会… eg: There is no telling what will happen. ※注意：动名词作主语时，其前可用名词所有格和形容词性物主代词修饰，即one’s doing sth.作主语。 eg: Tom’s being late again made his teacher angry. My going to Beijing University is my parents’ biggest dream. （3）动名词作宾语分为两种情况：动名词后的宾语和介词后的宾语 ①有些动词后只能接动名词作宾语，常见的有： avoid, advise, allow, admit, appreciate, consider, deny, enjoy, keep, finish, suggest, dislike, delay, risk, escape, imagine, mind, miss, permit, practice, fancy, can’t help, be busy, give up, can’t stand, feel like等。 eg: You must avoid being hurt when crossing the road. ②有些动词后即可接动名词也可接不定式作宾语，常见的有：

java_swing_入门教程

swing入门教程 swing简介(2009-04-20 23:52:40) U I组件简介在开始学习Swing之前，必须回答针对真正初学者的一个问题：什么是UI？初学者的答案是“用户界面”。但是因为本教程的目标是要保证您不再只是个初学者，所以我们需要比这个定义更高级的定义。所以，我再次提出这个问题：什么是UI？您可能把它定义成您按下的按钮、打字的地址栏、打开和关闭的窗口，等等，这些都是U I 的元素，但是除了在屏幕上看到的这些之外，还有更多都是U I 元素。比如鼠标、键盘、音量、屏幕颜色、使用的字体，以及一个对象相对于另一个对象的位置，这些都包含在U I 之中。实际上，在计算机和用户的交互之中扮演角色的任何对象都是U I 的组成部分。这看起来足够简单，但是您应当惊讶的是，有许多人和大型公司已经为它努力了很多年。实际上，现在有的大学专业的惟一课程就是研究这种交互。Swing的角色 Swing是Java平台的U I ——它充当处理用户和计算机之间全部交互的软件。它实际上充当用户和计算机内部之间的中间人。Swing 到底是如何做这项工作的呢？它提供了处理前面一节中描述的U I 各方面内容的机制： ?键盘：Swing 提供了捕捉用户输入的方法。 ?颜色：Swing 提供改变在屏幕上看到的颜色的方法。 ?打字的地址栏：Swing 提供了文本组件，处理所有普通任务。

音量：Swing 不太擅长。无论如何，Swing为您提供了创建自己的U I 所需要的所有工具 MVC Swing甚至走得更远一步，在基本的U I 原则之上又放上了一个公共的设计模式。这个设计模式叫做模型-视图-控制器（Model-Vie w-Co ntroller，MVC），它试图“把角色分开”。MVC 让负责显示的代码、处理数据的代码、对交互进行响应并驱动变化的代码彼此分离。有点迷惑？如果我为这个设计模式提供一个现实世界的非技术性示例，它就比较容易了。请想像一次时装秀。把秀场当成U I，假设服装就是数据，是展示给用户的计算机信息。现在，假设这次时装秀中只有一个人。这个人设计服装、修改服装、同时还在T 台上展示这些服装。这看起来可不是一个构造良好的或有效率的设计。现在，假设同样的时装秀采用MVC 设计模式。这次不是一个人做每件事，而是将角色分开。时装模特（不要与MVC 缩写中的模型混淆）展示服装。他们扮演的角色是视图。他们知道展示服装（数据的）适当方法，但是根本不知道如何创建或设计服装。另一方面，时装设计师充当控制器。时装设计师对于如何在T 台上走秀没有概念，但他能创建和操纵服装。时装模特和设计师都能独立地处理服装，但都有自己的专业领域。这就是MVC 设计模式背后的概念：让U I 的每个方面处理它擅长的工作。如果您仍然不明白，那么教程后面的示例有望消除您的迷惑——但是在您继续进行的时候，请记住基本的原则：用可视组件显示数据，同时让其他类操纵数据。

(完整版)java测试试卷(三)

JAVA语言基础内部测试题一．单项选择题（请选择最符合题目要求的答案）（每题2分） 1、在JAVA中，以下（c ）类的对象以键-值的方式存储对象 A、java.util.List B、java.util.ArrayList C、java.util.HashMap D、java.util.LinkedList 2、给定如下所示的JAVA代码，则运行时，会产生（ b ）类型的异常 String s = null; s.concat("abc"); A.ArithmeticException B.NullPointerException C.IOException D.ClassNotFoundException 3、给定如下Java 程序代码片段，编译运行这段代码，结果是（ b ）。 java.util.HashMap map = new java.util.HashMap(); map.put("name",null); map.put("name","Jack"); System.out.println(map.get("name")); A.null B.Jack C.nullJack D.运行时出现异常 4、分析如下Java代码，编译运行后将输出（b ）。 public class Test{ public Test(){} static void print(ArrayList al){ al.add(2); al=new ArrayList(); al.add(3); al.add(4); } public static void main(String[]args){ Test test=new Test(); ArrayList al=new ArrayList(); al.add(1); print(al); System.out.println(al.get(1)); } } A、1 B、2 C、3 D、4

现在分词用法讲解

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JAVA SWING 连接数据库的步骤

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6．创建执行语句对象stmt try{ String sql="insert into users values('name1','pass1')"; //上一行代码可以写成下一行的方式，试分析它的作用是什么？ //String sql="insert into users values('"+name+"','"+pass+"')"; stmt=conn.createStatement(); stmt.executeUpdate(sql); }catch(SQLException ex1){ } 7．完毕

现在分词的几种详细用法 (10)

现在分词的七种用法（一）作定语 1. 动词现在分词单独作定语，通常放在所修饰词前。The sleeping boy is Tom. 2. 现在分词短语作定语放在所修饰词的后面，意思同定语从句差不多。例如： Tell the children playing outside not to make too much noise. = Tell the children who are playing outside not to make too much noise. 3. 现在分词可相当于非限制性定语，常用逗号分开。 Tom, wearing beautiful clothes, followed me down the hill. = Tom, who is wearing beautiful clothes, followed me down the hill. 4. 有时现在分词可以和副词或名词构成复合词作定语。This is an English-speaking country. （二）作表语现在分词作表语多表示主语的特征。如amusing, discouraging, puzzling, refreshing, astonishing, exciting 等。The story is moving. （三）现分在句中作宾语补足语，这时现在分词和前面的宾语有逻辑上的“主表”关系或“主谓”关系。We all found his equipment interesting. (主表关系) I saw Mary going upstairs then. (主谓关系) （四）作状语现在分词作状语，其逻辑主语一般是句中的主语，如果不是，需在V-ing 形式前加名词或代词主格作逻辑主语。 1. 作原因状语，相当于原因状语从句。Being ill, Mary didn't come to school yesterday. 2. 作时间状语，相当于时间状语从句。Seeing their teacher coming, the students stopped talking. 如果现在分词表示的动作与谓语表示的动作同时发生，常在现在分词前加上when或while。 While waiting for the plane, I had a long talk with Simon. 3. 作条件状语。 V-ing 形式作条件状语时，相当于一个条件状语从句。Working harder, you'll be No. 1 in your class. 4. 作让步状语，相当于让步状语从句。Weighing almost two hundred jin, the stone was moved by him alone. 5. 作结果状语。He died, leaving nothing but debts. 6. 作伴随状语或方式状语。He sat by the roadside, begging. （五）现在分词的完成式表示它发生在主句谓语动词表示的动作之前。 Having finished his homework, he left the classroom. （六）现在分词的被动式当句子的主语是动作的承受者时，用V-ing 形式的被动式The factory being built now is a big one. （七）现在分词的否定形式是由“not + 现在分词”构成。 Not having been invited to the party, she had to stay home. 过去分词的用法一．1. 及物动词的过去分词作表语,与句子主语是被动关系,表示主语的状态,既表示被动,又表示完成. (1)_ The cup is broken. 茶杯破了. 2. 不及物动词的过去分词作表语,与句子主语是主动关系,表示主语的状态,只表示动作的完成. (2) He is retired. 他已退休. 3. 有些过去分词作表语时,构成的谓语很接近被动结构. (3)_The city is surrounded on three sides by mountains. 这座城市三面环山. 过去分词作表语【注意】过分词作表语与被动语态的区别:过去分词作表语,主要是表示主语的状态,而被动语态则表示动作. (1) The cup was broken by my little sister yesterday. 茶杯是昨天我小妹打碎的.(是被动语态,表示动作) (2) The library is now closed. 图书馆关门了.(过去分词作表语)

JavaSwing中处理各组件事件的一般步骤完整版

J a v a S w i n g中处理各组件事件的一般步骤集团标准化办公室：[VV986T-J682P28-JP266L8-68PNN]

Java Swing中处理各组件事件的一般步骤是： 1．新建一个组件（如JButton）。 2．将该组件添加到相应的面板（如JPanel）。 3．注册监听器以监听事件源产生的事件（如通过ActionListener来响应用户点击按钮）。 4．定义处理事件的方法（如在ActionListener中的actionPerformed中定义相应方法）。以上步骤我们可以用多种方法实现。但人们通常用二种方法。第一种方法是只利用一个监听器以及多个if语句来决定是哪个组件产生的事件；第二种方法是使用多个内部类来响应不同组件产生的各种事件，其具体实现又分两种方式，一种是匿名内部类，一种是一般内部类。为了说明如何使用上述三种方法实现事件的处理方法，我们建立一个简单的应用程序。该程序界面有两个按钮，当用户点击相应的按钮，就会弹出一个对话框显示相应的内容。通过这个简单程序，你可以实现自己更多、更复杂的用户界面程序。首先，我们利用单个监听器来实现该程序。我们定义一个名为Simple1的类来包括所有代码。所有的用户行为（如点击按钮）由一个监听器SimpleListenner中的actionPerformed方法来处理。以下是代码： import .*; import .*; public class Simple1 {

private static JFrame frame;dd(myPanel); (); (true); } } 让我们来看看以上代码是如何工作的。在main方法中，我们定义了一个JFrame，然后将面板Jpanel添加到窗体中，该面板包括两个按钮。相应的变量Frame,button1,button2定义在程序的开头部分。在程序入口main方法中，首先新建Simple1组件，通过构造器建立用户GUI，定义一个面板Jpanle,，增加两个按钮，然后利用将两个按钮加入到一个活动监听器SimpleLister中，最后，两个按钮添加到面板。当GUI 建立后，我们将面板添加到窗体并显示结果。当用户点击按钮时，程序调用actionPerformed方法，通过if语句来判断是哪一个按钮被点击，然后在对话框中显示相应的内容。利用一个监听器来处理事件的缺点是，当程序比较复杂时，需要一大串的if 语句来实现，程序代码较难阅读与维护。当然，如果处理的事件较少，这种方式比较简单。通过使用匿名内部类可以解决上述存在的问题。使用简单的匿名内部类作为addActionListener的变量即可。以下是实现代码：

java考试

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异常习题

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现在分词的用法

现在分词的用法现在分词（Present Participle ）（又称-ing形式、现在进行式），是分词的一种，分词又分为现在分词和过去分词，它们都是非限定动词，即在句子里面不能单独充当谓语，但能充当其它的一些成分（定语，表语，补语和状语），并且它们具有动词的性质，所以又是类动词的一种。 ☆现在分词的两个基本特点： 1. 。例如： a developing country. 一个发展中的国家，boiling water 沸水， risi ng sun 冉冉升起的太阳。（试比较： a developed country —个发达国家，boiled water 白开水，rise n sun 升起的太阳） 2. 在语态上表示主动。例如：the ruling class 统治阶级， the exploiting class 剥削阶级。（试比较： the ruled class 被统治阶级，the exploited class 被剥削阶级） ':构成形式 doing 现在分词表示主动的，或进行的动作 ?：时态与语态三：否定式：所有否定式都是在—ing前面加not

1）现在分词的时态：现在分词本身不能表示具体的时间概念，其动作发生的时间只能是相对于谓语动作发生时间相对而言的。这一点和不定式用法相同。 A）现在分词的一般式：doing 表示分词的动作和谓语动作同时或几乎同时发生。或是谓语动作发生时，分词的动作正在发生过程中。女口： Looking back, I found she was washing clothes. She smelt something burning.（smelt 发生在 burning 的过程中。）她闻到有东西烧焦了。 She sat on the chair, readi ng a no vel. B）现在分词的完成式：havi ng do ne 表示现在分词的动作发生在谓语动作之前。 Having worked for 2 hours, we had a rest. Not havi ng received his letter, we all felt worried. 2）现在分词的语态：现在分词用主动还是被动，决定于它的逻辑主语。如果现在分词的逻辑主语是分词动作的执行者，用主动。反之，用被动。

跟我学Java入门到精通培训教程——利用Eclipse Swing可视化开发实现快闪屏

1.1利用Eclipse Swing可视化开发实现应用程序中的快闪屏 1、新建一个Swing JFrame（代表主窗口）（1）选择File>New>Other... 菜单，然后再选择MyEclipse>Swing>Matisse Form （2）点击Next按钮输入包名称为com.px1987.javaapplication.swing.matisse，类名称为SplashMainFrame，并选择Swing JFrame类型。

（3）点击“Finish”按钮，将进入可视化设计器视图 2、设置SplashMainFrame窗口的属性（1）取消标题条及控制按钮

将窗口的undecorated属性设置为true。（2）不允许改变窗口的大小，设置resizeable为false。 3、定位及设置窗口的大小在源代码视图中找到该窗口的构造方法，在其中的initComponents初始化函数后面添加如下的代码： public SplashMainFrame() { initComponents(); /** * 获取整个屏幕的尺寸大小 */ Dimension scmSize=Toolkit.getDefaultToolkit().getScreenSize(); /** * 背景大图像的宽和高 */ int nImageWidth=570; int nImageHeight=247;

/** * 设置快闪屏窗口的大小 */ setSize(nImageWidth,nImageHeight); /** * 设置快闪屏窗口在显示屏幕内的居中位置显示 */ setLocation(scmSize.width/2-nImageWidth/2, scmSize.height/2-nImageHeight/2); } 最后为如下的代码状态