J2EE的入门问题，散散分了

象JSP、Servlet这些程序是运行在WEB容器中的，而TOMCAT只能充当WEB容器。
如果要运行EJB那么必须使用象J2EE、Weblogic或WebSphere 这样的服务器，而Weblogic、WebSphere 又充当中间件的角色。J2EE用来解决分布的企业级方案，它是一种n层结构。
它的优点在于：
    1、平台独立性
    2、可重用性
    3、模块化

希望看一下thinking in java应该会明白一些。这个大家说都说不好。
其实我看吧。一种语言的存在必定有他的原因。讨论的这个话题够大。呵呵

J2ee是一个分布式体系结构，与.NET一样，主要是面向企业集应用的，jsp只是服务器端一种脚本语言，主要用于网页显示，是面向浏览器的。而j2ee的体系结构是由客户端(browser等等)+jsp(负责客户端显示+web服务器)&ejb(用于封装企业业务逻辑+应用服务器(weblogic/websphere))+数据服务器！组成的！

一般书先介绍jdbc jta javamail jndi等接口
在介绍servlet jsp
再介绍ejb
再是xml soap corba
再讲一点安全的知识
再列个例子
再是附录a b .............
结束!

客户端(browser等等)在Ｊ２ＥＥ中是怎样的一个概念？？？

客户端在J2EE里面算是CLIENT的CLIENT把，一般来说，jsp,applet等算是client了

其实SCEA的教材上说的很清楚。
J2EE适合于：EBUSINESS
ERP
WORKFLOW
所以J2EE并不是万能的，但是它是适合于大型企业的。为什么现在这么多人学它，就是因为这个市场好做，而且J2EE相对来说稳定，开发迅速，并有一定开放性。

推荐看<Master EJB>the second Edition

j2ee 里的核心是ejb
ejb的核心在于复用性和透明性当你开发过大的系统你就会体会把各个层次分清楚对开发有多大的好处
表示层->jsp,html
业务逻辑程->ejb
数据层->你的数据库

J2EE主要是使用在一些大型的项目中，我参与的是社保项目应用服务器一般是管理，部属EJB用的，而J2EE的核心就是EJB

j2ee是一个specification
推荐看MasterEJB2写得很详细
绝对值的一看

J2ee是一个分布式体系结构，与.NET一样，主要是面向企业集应用的，jsp只是服务器端一种脚本语言，主要用于网页显示，是面向浏览器的。而j2ee的体系结构是由客户端(browser等等)+jsp(负责客户端显示+web服务器)&ejb(用于封装企业业务逻辑+应用服务器(weblogic/websphere))+数据服务器！组成的！
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我觉得 cool_ice(冷冰) 所说的有点问题，我觉得ejb这里有了weblogic,jsp的那边就可以不用web服务器了啊，应该是对的吧。

推荐看MasterEJB2和think in java

先明白一点:J2EE是一个构架,类似于.NET. 基于此架构产生一个系统.

think in java
MasterEJB2

FREQUENTLY ASKED QUESTIONS
Q: What is the JavaTM 2 Platform, Enterprise Edition (J2EETM)?
JavaTM 2 Platform, Enterprise Edition (J2EETM) is a set of coordinated specifications and practices that together enable solutions for developing, deploying, and managing multi-tier server-centric applications. Building on the JavaTM 2 Platform, Standard Edition (J2SETM), J2EE adds the capabilities necessary to provide a complete, stable, secure, and fast Java platform to the enterprise level. It provides value by significantly reducing the cost and complexity of developing and deploying multi-tier solutions, resulting in services that can be rapidly deployed and easily enhanced. Q: What are the main benefits of J2EE?
J2EE provides the following:
Faster solutions delivery time to et. J2EE uses "containers" to simplify development. J2EE containers provide for the separation of business logic from resource and lifecycle management, which means that developers can focus on writing business logic -- their value add -- rather than writing enterprise infrastructure. For example, the Enterprise JavaBeansTM (EJBTM) container (implemented by J2EE technology vendors) handles distributed communication, threading, scaling, transaction management, etc. Similarly, Java Servlets simplify web development by providing infrastructure for component, communication, and session management in a web container that is integrated with a web server.
Freedom of choice. J2EE technology is a set of standards that many vendors can implement. The vendors are free to compete on implementations but not on standards or APIs. Sun supplies a comprehensive J2EE Compatibility Test Suite (CTS) to J2EE licensees. The J2EE CTS helps ensure compatibility among the application vendors which helps ensure portability for the applications and components written for J2EE. J2EE brings Write Once, Run AnywhereTM (WORATM) to the server.
Simplified connectivity. J2EE technology makes it easier to connect the applications and systems you already have and bring those capabilities to the web, to cell phones, and to devices. J2EE offers Java Message Service for integrating diverse applications in a loosely coupled, asynchronous way. J2EE also offers CORBA support for tightly linking systems through remote method calls. In addition, J2EE 1.3 adds J2EE Connectors for linking to enterprise information systems such as ERP systems, packaged financial applications, and CRM applications.
By offering one platform with faster solution delivery time to et, freedom of choice, and simplified connectivity, J2EE helps IT by reducing TCO and simultaneously avoiding single-source for their enterprise software needs. Q: What technologies are included in the J2EE platform? The primary technologies in the J2EE platform are: Java TM API for XML-Based RPC (JAX-RPC), JavaServer PagesTM (JSPsTM), Java Servlets, Enterprise JavaBeansTM (EJBsTM), J2EETM Connector Architecture, J2EE Management Model, J2EE Deployment API, Java Management Extensions (JMX), J2EE Authorization Contract for Containers, Java API for XML Registries (JAXR), Java Message Service (JMS), Java Naming and Directory InterfaceTM (JNDITM), Java Transaction API (JTA), CORBA, and JDBCTM data access API. Q: How does J2EE relate to Enterprise JavaBeans technology? Enterprise JavaBeans (EJB) technology is the basis of J2EE. EJB technology provides the scalable architecture for executing business logic in a distributed computing environment. J2EE makes the life of an enterprise developer easier by combining the EJB component architecture with other enterprise technologies to solutions on the Java platform for seamless development and deployment of server side applications.

Q: How are J2EE technology and the Sun ONE platform related? The Sun ONE portfolio of products and technologies is built on the J2EE architecture, which defines the service container for the platform. Developers familiar with J2EE technology can easily apply their skills to building software, including Web services, using the Sun ONE products. For more information, see the Sun ONE for Developers Web site. Q: Who needs J2EE? ISVs need J2EE because it gives them a blueprint for providing a complete enterprise computing solution on the Java platform. Enterprise developers need J2EE because writing distributed business applications is hard, and they need a high-productivity solution that allows them to focus only on writing their business logic and having a full range of enterprise-class services to rely on, like transactional distributed objects, message oriented middleware, and naming and directory services. Q: Is J2EE available under the community source program? Yes. The Java 2 SDK, Enterprise Edition is available under Sun's Community Source Licensing program. For more information on Sun's community source program, see http://www.sun.com/communitysource. Q: Are there compatibility tests for J2EE? Yes. The J2EE Compatibility Test Suite (CTS) is available for J2EE. The J2EE CTS contains over 5,000 tests for J2EE 1.2 and will contain more for later versions. This test suite tests compatibility by performing specific application functions and checking results. For example, to test the JDBC call to insert a row in a database, an EJB component makes a call to insert a row and then a call is made to check that the row was inserted. Q: What is the JavaTM Enterprise BluePrints?The JavaTM Enterprise BluePrints are the best practices philosophy for the design and building of J2EE-based applications. The design guidelines document provides two things. First, it provides the philosophy of building n-tier applications on the Java 2 platform. Second, it provides a set of design patterns for designing these applications, as well as a set of examples or recipes on how to build the applications.Q: What is the purpose of the Reference Implementation? The purpose of the reference implementation is to validate the specifications. In short, it is to prove that the specifications can be implemented. Q: Why don't you allow the binary Reference Implementation to be deployed or redistributed? We do not allow the binary reference implementation to be deployed or redistributed because it is not supported and it could distract developers from robust, commercial J2EE implementations. We recommend that people use those implementations which have the support of vendors and are tested and built for performance and reliability. The J2EE Reference Implementation is designed to validate the test suite and to be clearly understandable to vendors who want to see how we implemented a specific specification. These design goals sometimes conflict with the goals of producing a highly performing, robust, full featured implementation. Q: What is the relationship of the Apache Tomcat open-source application server to the J2EE reference implementation?Tomcat is based on the original reference implementation of the JavaServer Pages (JSP) and Java Servlet specifications, which was donated by Sun to the Apache Software Foundation in 1999. Sun continues to participate in development of Tomcat at Apache, focusing on keeping Tomcat current with new versions of the specifications coming out of the Java Community Source ProcessSM. Sun adapts and integrates the then-current Tomcat source code into new releases of J2EE RI. However, since Tomcat evolves rapidly at Apache, there are additional differences between the JSP and Servlet implementations in the J2EE and in Tomcat between RI releases. Tomcat source and binary code is governed by the ASF license, which freely allows deployment and redistribution. Q: Is Web Services supported in J2EE? Web Services is an essential component in the J2EE platform. J2EE provides a framework for developing and deploying web services on the Java platform. The JavaTM API for XML-based RPC (JAX-RPC) enables Java technology developers to develop SOAP based interoperable and portable web services. Developers use the standard JAX-RPC programming model to develop SOAP based web service clients and endpoints. A web service endpoint is described using a Web Services Description Language (WSDL) document. JAX-RPC enables JAX-RPC clients to invoke web services developed across heterogeneous platforms. In a similar manner, JAX-RPC web service endpoints can be invoked by heterogeneous clients. For more info, see http://java.sun.com/webservices/. 1.3 Frequently Asked QuestionsA list of Frequently Asked Questions for the J2EE SDK 1.3 FCS release is available at http://java.sun.com/j2ee/sdk_1.3/faq.html.BrandingQ: What is the difference between being a J2EE licensee and being J2EE compatible?A J2EE licensee has signed a commercial distribution license for J2EE. That means the licensee has the compatibility tests and has made a commitment to compatibility. It does not mean the licensees products are necessarily compatible yet. Look for the J2EE brand which signifies that the specific branded product has passed the Compatibility Test Suite (CTS) and is compatible.Q: Where can I find more information on J2EE? For more information about J2EE and how to get the specification, see http://java.sun.com/j2ee/.

调试易

J2EE的入门问题，散散分了

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