ejb | 易学教程

Plug Bean to JBoss with JNDI

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问题 I wonder how object (if it matter I need EJB) can be plugged to JBoss (5.0) with JNDI? I have following bean definition in my Spring applicationContext.xml : <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory" /> </bean> <tx:annotation-driven transaction-manager="transactionManager" /> <context:annotation-config/> <bean id="myServiceFacade" class="org.springframework.jndi

EJB到底是什么，真的那么神秘吗？？

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EJB到底是什么，真的那么神秘吗？？分类： JAVA学习-基础篇 2010-08-02 21:26 37965人阅读评论 (127) 收藏举报 ejb 服务器数据库服务器网络分布式计算数据库 1. 我们不禁要问，什么是"服务集群"？什么是"企业级开发"？既然说了EJB 是为了"服务集群"和"企业级开发"，那么，总得说说什么是所谓的"服务集群"和"企业级开发"吧！这个问题其实挺关键的，因为J2EE 中并没有说明白，也没有具体的指标或者事例告诉广大程序员什么时候用EJB 什么时候不用。于是大家都产生一些联想，认为EJB"分布式运算"指得是"负载均衡"提高系统的运行效率。然而，估计很多人都搞错了，这个"服务群集" 和"分布式运算"并没有根本解决运行负载的问题，尤其是针对数据库的应用系统。为什么？我们先把EJB 打回原形给大家来慢慢分析。 2. 把EJB 掰开了揉碎了我们把EJB 的概念好好的分析一下，看看能发现些什么蛛丝马迹。 3.1 EJB 概念的剖析我们先看一下，EJB 的官方解释：商务软件的核心部分是它的业务逻辑。业务逻辑抽象了整个商务过程的流程，并使用计算机语言将他们实现。 …… J2EE 对于这个问题的处理方法是将业务逻辑从客户端软件中抽取出来，封装在一个组件中。这个组件运行在一个独立的服务器上，客户端软件通过网络调用组件提供的服务以实

Java EJB JNDI Beans Lookup Failed

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问题 I have the following structure in place: <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.screening</groupId> <artifactId>screening</artifactId> <version>1.0-SNAPSHOT</version> <packaging>pom</packaging> <name>Screening Java Parent</name> <modules> <module>Module1</module> <module>Module2<

why pool stateless bean?

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问题 Normally we use singleton instance for business / dao layer. What is the reason behind pooling stateless session beans in case of EJBs? 回答1: The "stateless" in the name refers to session conversation state, i.e. state that persists between invocations of the bean, retained for the duration of the session. However, stateless session beans are still permitted to have instance variables. Those instance variables should not relate to the conversation state, but are "shared" between clients. In

JAR，WAR，EAR区别

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以最终客户的角度来看，JAR文件就是一种封装，他们不需要知道jar文件中有多少个.class文件，每个文件中的功能与作用，同样可以得到他们希望的结果。除jar以外对于J2EE来说还有war和ear。区别见下表： JAR WAR EAR 英文 Java Archive file Web Archive file Enterprise Archive file 包含内容 class 、 properties 文件，是文件封装的最小单元；包含 Java 类的普通库、资源（ resources ）、辅助文件（ auxiliary files ）等 Servlet 、 JSP 页面、 JSP 标记库、 JAR 库文件、 HTML/XML 文档和其他公用资源文件，如图片、音频文件等除了包含 JAR 、 WAR 以外，还包括 EJB 组件部署文件 application-client.xml web.xml application.xml 容器应用服务器（ application servers ）小型服务程序容器（ servlet containers ） EJB 容器（ EJB containers ）级别小中大 (1)EAR文件的打包 EAR文件包括整个项目，内含多个 EJB Module（JAR文件）和 Web Module（WAR文件）。

Best way to interact with EJBs in Java EE

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问题 I have a moderate sized Java EE 6 project that uses several EJBs, including one which sole purpose is managing database calls through JPA. My question is what is the best way to add a new class that does some random bit of functionality and then calls the database access EJB to persist the data from this class. Does this new class have to be an EJB if it needs access to annotations and injections? Does it have to be an EJB if it has to be deployed with the rest of the project? I was told that

How to handle internal calls on Spring/EJB/Mockito… proxies?

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问题 As you many know when you proxy an object, like when you create a bean with transactional attributes for Spring/EJB or even when you create a partial mock with some frameworks, the proxies object doesn't know that, and internal calls are not redirected, and then not intercepted either... That's why if you do something like that in Spring: @Transactionnal public void doSomething() { doSomethingInNewTransaction(); doSomethingInNewTransaction(); doSomethingInNewTransaction(); } @Transactional

JBoss Seam: components injected into POJOs, but not Session Beans

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问题 I have a Seam component that handles login, with the name "authenticator": @Name("authenticator") public class AuthenticatorAction implements Authenticator { @PersistenceContext private EntityManager em; @In(required=false) @Out(required=false, scope = SESSION) private User user; public boolean authenticate(){ ... } } This works just fine, Seam injects the EntityManager instance. However, as soon as I add the @Stateless annotation, none of the injection happens! In this case, the

web.xml配置文件元素详解

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web.xml配置文件常用元素及其意义预览 <web-app>  <display-name></display-name>  <description></description>  <context-param></context-param>  <filter></filter>  <filter-mapping></filter-mapping>  <listener></listener>  <servlet></servlet> <!--服务器一般为servlet提供一个缺省的URL

Cannot use dependency jboss-javaee-6.0 in my Maven project

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问题 I have set up a maven project with JBoss 7.1.1 and I want to use JavaEE libraries. In the root pom.xml I have set: <repositories> <repository> <id>jboss</id> <url>https://repository.jboss.org/nexus/content/groups/public/</url> </repository> </repositories> I have this in the root pom.xml and and in the ejb maven module´s pom.xml: <dependency> <groupId>org.jboss.spec</groupId> <artifactId>jboss-javaee-6.0</artifactId> <version>3.0.2.Final</version> <scope>provided</scope> <type>pom</type> <