J2EE简介-毕业论文外文文献翻译

1、英文原文：J2EE synopsis:J2EE is a set is completely different in the traditional application development technical frame, contains many modules, mainly may simplify, and the standard application systems development and the deployment, then enhance the probability, the security and use the value again.The

2、 J2EE core is a group of technology standard and the guide, contains each kind of module, the service construction and the technical level, has the common standard and the specification, lets each kind rely on the J2EE construction between the different platform, has the good compatibility, between

3、information product each other who the solution behind the enterprise used in the past is unable compatibly, the enterprise interior or exterior exchanged with difficulty predicament.At present, the Java 2 platforms have 3 editions, they are suitable for the bantam and smart card Java 2 platform Mic

4、ro version (Java 2 Platform Micro Edition, J2ME), are suitable for the tabletop systems Java 2 platform standard edition (Java 2 Platform Standard Edition, J2SE), are suitable for the foundation server application procedure and the service Java 2 platform enterprise version (Java 2 Platform Enterpri

5、se Edition, J2EE).J2EE is one kind simplifies the enterprise solution using the Java 2 platforms the development, the deployment and the management related complex question architecture. The J2EE technologys foundation was the core Java platform or the Java 2 platform standard edition, J2EE has not

6、only consolidated in standard edition many merits, for example compiled one time, everywhere moved the characteristic, convenience deposit database JDBC API, the CORBA technology as well as can in the Internet application protect data safe mode and so on, meanwhile has provided to EJB (Enterprise Ja

7、vaBeans), Java Servlets API, JSP (Java Server Pages) as well as the XML technology comprehensive support. Its final goal is becomes one to be able to cause the enterprise exploiters to reduce largely puts in the market hour the architecture.The J2EE architecture provides the intermediate level integ

8、ration frame to usefor not to need too many expenses satisfiedly and to need the high usability, the redundant reliability as well as the extendibility application demand. Through provided the unification the development platform, J2EE reduced the development multi-layer application expense and the

9、complexity, simultaneously provided to the existing application procedure integrates the powerful support, supported Enterprise JavaBeans completely, had the good guide to support packs and deploys the application, the increase table of contents support, strengthened the safety mechanism, enhanced t

10、he performance.The J2EE to building have scalability, flexibility, easy maintenance businesssystem provides a good mechanism:Retain existing IT assets: because enterprise must adapt to the new commercial demand, by means of the existing enterprise information system in investment, rather than re-ena

11、cted overall scheme is very important. So, a gradual (not radical, completely negative) way above the existing system established the server platform mechanism is not fair that the company needs. Can make full use of the user J2EE, as some of the original investment companies use the Tuxedo, IBM CIC

12、S BEA,IBM VisiBroker Inprise Encina, and Netscape apply Server. This is possible because the J2EE extensive industry supported and some important enterprise computing field supplier to participate. Each supplier to existing customer provides no abandonedexisting investment into portable J2EE field u

13、pgrade path. Based on the J2EE platform because the product can almost in any operating system and hardware configurations to run on existing operating system and hardware can also be retained use.Efficient development: the J2EE allows companies to some generic, very tedious tasks to a server to com

14、plete the middleware vendors. So that developers can focus on how to create business logic, correspondingly shorten the development time. Senior middleware vendors provide the following these complex middleware services:State management service - let developers to write less code, dont care about ho

15、w to manage state, so can complete application development faster.Persistent services - lets developers dont have to encode data access logic can write applications that can generate a lighter, and database irrelevant applications, this application easier to development and maintenance.Distributed s

16、hare data object CACHE service - let development staffing high-performance systems, greatly enhance the loft deployment.3.Support heterogeneous environment: the J2EE can develop the heterogeneous environment can be deployed in transplant programs. Based on the J2EE applicationis not dependent on any

17、 specific operating system, middleware, hardware. So the reasonable design based on J2EE program just can be deployed to develop a various platforms. This in a typical heterogeneous enterprise computing environment is very critical. The J2EE standard also allows customers to order and J2EE compatibl

18、e third-party ready-made components, put them to deploy on heterogeneous environment, save by oneself make of the cost of the whole scheme.Scalability: enterprise must choose a server not fair Taiwan, the platform should be able to offer excellent scalability to satisfy those in their system on the

19、large number of new customers of commercial operation. Based on the J2EE platformapplication can be deployed to all operating systems. For example can be deployed to high-end UNIX and mainframe systems, this system can support single 64 to 256 processor. (this is exceed NT server supplier of the) J2

20、EE field provides a more extensive load balancing strategy. Can eliminate system bottlenecks, allow multiple servers integration to deploy. The deployment of thousands of processors, realize flexible system, highly satisfied future commercial application needs.Stable usability: a server platform mus

21、t be able to round-the-clock operation not fair to meet the needs of our customers, partners. Because the INTERNET is the globalization, everywhere, even at night as planned downtime also may cause seriousdamage. If it hangs, it will have disastrous consequences.The J2EE deployed to reliable operati

22、ng environment, they support long-term usability. Some J2EE deployed in WINDOWS environment, customers also can choose to robust performance better operating systems such as from Solaris, IBM OS / 390. The most robust operating system can achieve 99.999% availability or just 5 minutes downtimeevery

23、year. This is real-time strong business system ideal choice.J2EE four layers modelThe J2EE multilayer distributed applications used by function, application logic model into components, each application components according to their shape layer distribution in different machine. In fact, from the or

24、iginal intention is to design the J2EE solve two layer mode (are) / server the disadvantages of traditional mode, in client bear too many roles and appear bloated, in this mode, the first deployment, but difficult to compare easy when upgrade or improved, scalability, and often not ideal based on so

25、me proprietary agreement is usually some kind of database agreement. It makes reuse business logic and interface logic is very difficult. Now the J2EE multilayer the enterprise applications model of two layer of the model different levels cut into many layers. A DuoCengHua application for different

26、each service to provide a separate layer, the following is typical of the four layers J2EE structure:Running on a client machine customer layer components。Run on J2EE server Web layer components。Run in the business logic of the J2EE server layer components。On a server running on EIS Enterprise infor

27、mation system (Enterprise information system) layer of software below is typical of the four layers J2EE structure:The J2EE application componentsThe J2EE application is by components. The J2EE is a separatefunction ofcomponent software units, which passed the relevant classes and file assemble J2EE

28、 application, and with other component interaction. The J2EE specification of J2EE defined in the following components:Application client program and applets is customer layer components.Java Servlet and JavaServer web (JSP) is web layer components.Enterprise JavaBeans (EJB) is a business layer comp

29、onents.Customer layer componentsBased on J2EE application can be a web form, also can be based on the traditional way.Web layer componentsThe J2EE web layer components can be the JSP page or Servlets. According to the J2EE specification, static HTML pages and Applets isnt web layer components. As th

30、e chart shows, the customer layer that web layer may contain some JavaBean object to handle user input, and send to run in the input of bean enterprise business layer to undertake handling.Business layer componentsBusiness layer code used to satisfy Banks, retail logic, finance and other special bus

31、iness areas in need, by operation of enterprise business layer process. The figure below shows the bean bean is a enterprise how receiving data from the client program, undertake handling (if necessary), concurrent to EIS layer stored, this process can also reverse.There are three kinds of enterpris

32、e-level bean: session (session) beans beans,the entity (entity), and message driver ( - driven) bean said beans. The conversation with the client program. When the temporary interaction after client program execution, bean and related data session will disappear. Instead, entity bean said databaseta

33、ble ever recorded in line. When the client program suspendedor closed servers, you will have the potential of service guarantees entity to preserve the data bean bean. News drive combines the bean and JMS news session the characteristics of listeners, allowing a business layer component asynchronous

34、 receiving JMS news.The enterprise information system layerThe enterprise information system layer processing enterprise information system software including enterprise infrastructure system such as enterprise resource planning (ERP), mainframe transaction processing, database system, and other leg

35、acy information system. For example, J2EE application components can in order to database connections need access to the enterprise information systemThe J2EE structureThis based on components have platform-independent characteristics of J2EE structure makes the J2EE program is very simple, because

36、the writing business logic being sealed into reusable components, and the form of J2EE server to container for all component types provide backend service. Because you dont have to develop their own this service, so you can focus on solving business problems.Containers and serviceContainers set cust

37、om made J2EE server inner support provided, including safety, business management, JNDI (Java Naming and Directory addressing, with) services such as remote connection, the most important listed below several servicesThe J2EE safety (Security) model can let you to configure the web components or ent

38、erprise bean, so that only authorized users can access system resources. Each customer belong to a special role, and every character only allow activate a particular method. You should be in enterprise bean decorate description characters and can be activated statement of the method. Because of this

39、 statement sex, you dont have to write strengthening methods of safety rules.The J2EE affairs Management (Transaction Management) model allows you tospecify a affairs of the relationship between all methods, such a affairs as all the way to a single unit. When the client activate a bean and the meth

40、od of enterprise Management affairs container intervention. For a container management in enterprise bean in affairs, you dont have to encode affairs of the border. The code distributed transactions required control will be very complicated. You need only to decorate documents state enterprise bean

41、described the transaction attribute, instead of writing and debug complex code. Will be read this document and container for you deal with this enterprise bean affairsJNDI addressing (JNDI Lookup) services to the business enterprise insidemultiple names and directory services provide a unified inter

42、face, such application component can access names and directory services.。The J2EE Remote connections (Remote login) model management are enterprise between Client and the lower the bean bean interaction. When a enterprise after creation, a Client can call it methods like it and Client as in the sam

43、e virtual machine.Survival Cycle Management (act enterprise Management) model Management pa bean created and removed, a enterprise bean in its survival Cycle will be after several state. Container enterprise bean, and create instances pool and activities in the available, and state of will eventuall

44、y move him removed from the vessel. Even if can call the enterprise bean remove method, and create containers will also carry out these tasks in the background.Database Connection pool (Database Connection Pooling) model is a valuableresource. Access database connection is a time-consuming work, and

45、 number of connections is very limited. Containers through management to reduce these problemsconnection pool. Bean enterprise from the pool quick access connections. In the release of bean bean for other connected use. Beans affairs.Vessel typesThe J2EE application components can be installed to de

46、ploy on several containers to:EJB container management all the J2EE application of enterprise bean enterprise-level bean and their implementation. The containers run on J2EE server.。Web container management all the J2EE application JSP page and Servlet component execution. Web components and their c

47、ontainers run on J2EE server.Application client container management all the J2EE application applications client component of execution. Application client and their containers run on J2EE server.Applet container is running on a client machine web browser plugin and Java combination.The core API an

48、d J2EE componentsThe J2EE platform by a set of service (Services for), application program interface (APIs) and agreement constitutes for development based on Web, it providesthe functions of multi-layer application support, the 13 to J2EE specification for simple description (somewhere here only si

49、mple description) :JDBC Database (Java login) : JDBC API for visit different Database provides a unified approach, like the same, JDBC to developers by ODBC shielding some detail problems, in addition, JDCB the Database access also have platform-independent characteristics.JNDI (Java Name and Direct

50、ory JNDI API with) : by Name and Directoryservice for execution. It provides a consistent model to access and operation of enterprise-level resources such as DNS and LDAP, local file systems, or application server objects.The EJB (Enterprise JavaBean) : J2EE technology is a body of won wide attentio

51、n isand EJB to reach the same goal.RMI (Remote Invoke) : as of as its name suggests, the Remote object RMI agreement calls Method. It USES the serialized way in client and server transfer data. RMI is being used more at the bottom of the EJB agreement.Java IDL/CORBA: in Java (IDL, under the support

52、of the developers can willJava and CORBA integrated together. They can create Java objects and carried in CORBA, ORB or they can create Java classes and as and other ORB of CORBA object launched with clients. After a kind of method provides another kin one of the reasons the EJB. They provide a fram

53、ework to develop and implement business logic, which is distributed significantly simplified have scalability and highly complex enterprise applications development. EJB standard defines how and when EJB components of their vessels interaction. Container is responsible for providing public services,

54、 such as directory services, business management, safety, resources buffer pool and fault tolerance. But here, it is worth noting, EJB is not the only way to realize the J2EE. Because the openness,makes some J2EE with a firm can parallel manner d of way, by which it Java can be used to put your new

55、applications and the old system combined.The JSP (Java Server web) : the JSP page from the HTML code and the Java code embedded them together. Server in a page is the client requested to these Javacode after processed and then will generate the HTML page back to the client browser.Java Servlet: Serv

56、let is a small Java program, it expanded the Web server functions. As a server-side application, when requested started, this and CGI Perl script very similar. The function is mostly Servlet provide with JSP similar, but different implementation. The JSP are usually most HTML code embedded in a smal

57、l amount of Java code, and servlets all written by Java and generating HTML.XML (Extensible creating Language) : XML is a can be used to define other Markup Language Language. It is used in different business process share data. XML development and Java is independent of each other, but it has the s

58、ame goal and Java is platform independence. Through the combination will Java and XML, you can get a perfect has platform independence solutions.JMS (Java macro Service) : MS is used to and facing the Message oriented middleware mutual communication application program interface (API). It supports b

59、oth point-to-point domain, a support publish/subscribe (publish/by the domain) type,and to provide the following types of support: approved message transfer, the transmission, consistency non-business messages with persistent subscriber information and support. JMS also provides another way for you

60、to the application and the old backend system combined.JTA (Java Architecture) : Transaction JTA defines a standard API, application system which can access various affairs monitoring.JTS (Java Transaction Service) : JTS is CORBA basic offer OTS affairs monitoring achieved. JTS stipulated affairs ma