ejb3 EntityBean 例子

最近项目录要用到EJB3.0, 对于象我一样没有接确过ejb的人来说, 开发首个应用还是比较复杂的, 下面是一个EJB3.0 Entity Bean开发实例,

**** EntityBean 开发****

1. 配置应用相关的数据源(针对不同的数据库进行不同的配置)

   这里按照MySQL5进行配置.

1.1 找到MySQL的JDBC驱动jar(我这里是:mysql.jar),将该jar

   文件复制到[jboss-install-root]\server\default\lib下

1.2 编写MySQL的数据源配置文件 "mysql-ds.xml"

    内容如下：

    <?xml version="1.0" encoding="UTF-8"?>

   <datasources>

    <local-tx-datasource>

    <jndi-name>COOTMEMySQLDS</jndi-name>

    <connection-url>jdbc:mysql://localhost:3306/test?useUnicode=true&amp;characterEncoding=GBK</connection-url>

    <driver-class>org.gjt.mm.mysql.Driver</driver-class>

    <user-name>root</user-name>

    <password>admin</password>

    <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name>

    <metadata>

     <type-mapping>mySQL</type-mapping>

    </metadata>

    </local-tx-datasource>

   </datasources>

  重新启动JBOSS服务器，检查http://localhost:8080/jmx-console路径下的

  jboss.jca出现如下的配置信息为成功配置该数据源:

  name=COOTMEMySQLDS,service=DataSourceBinding

  name=COOTMEMySQLDS,service=LocalTxCM

  name=COOTMEMySQLDS,service=ManagedConnectionFactory

  name=COOTMEMySQLDS,service=ManagedConnectionPool

  如果未出现，则检查相关的配置是否正确？

1.3 实现persistence.xml文件

  <persistence>

    <!-- Database name -->

    <persistence-unit name="test">

    <!-- Configurated in jboss DS -->

    <jta-data-source>java:/COOTMEMySQLDS</jta-data-source>

    <properties>

     <!-- "update" dont delete tables and update table's data -->

     <property name="hibernate.hbm2ddl.auto" value="update"/>

    </properties>

   </persistence-unit>

  </persistence>

  注意：该文件请放置[工程目录]\src\META-INF\persistence.xml下



1.4 实现EntityBean

    此处为：Student.java

  package com.cootme.ejb3.entity;



  import java.io.Serializable;



  import javax.persistence.Column;

  import javax.persistence.Entity;

  import javax.persistence.Table;

  import javax.persistence.Id;



  @SuppressWarnings("serial")

  @Entity

  @Table(name = "Student")

  public class Student implements Serializable{

   private Integer id;

   private String name;

   private Integer age;

   private String sex;

   private String mobile;

   private String email;

 

   @Id

   public Integer getId() {

    return id;

   }

   public void setId(Integer id) {

    this.id = id;

   }

 

   @Column(nullable=true)

   public String getName() {

    return name;

   }

   public void setName(String name) {

    this.name = name;

   }

 

   @Column(nullable=true)

   public Integer getAge() {

    return age;

   }

   public void setAge(Integer age) {

    this.age = age;

   }

 

   @Column(nullable=true)

   public String getSex() {

    return sex;

   }

   public void setSex(String sex) {

    this.sex = sex;

   }

 

   @Column(nullable=true)

   public String getMobile() {

    return mobile;

   }

   public void setMobile(String mobile) {

    this.mobile = mobile;

   }

 

   @Column(nullable=true)

   public String getEmail() {

    return email;

   }

   public void setEmail(String email) {

    this.email = email;

   }

  }



1.5 实现SessionBean的业务操作类

1.5.1 业务类接口:StudentDAO.java

  package com.cootme.ejb3.seesion.student;



  import java.util.List;



  public interface StudentDAO {

   public List getStudentList();

   public List getStudentByName(String _name);

  }



1.5.2 业务类实现:StudentDAOBean.java

  package com.cootme.ejb3.seesion.student.bean;



  import java.util.List;



  import javax.ejb.Stateless;

  import javax.ejb.Remote;



  import javax.persistence.PersistenceContext;

  import javax.persistence.EntityManager;

  import javax.persistence.Query;



  import com.cootme.ejb3.seesion.student.StudentDAO;



  @Stateless

  @Remote(StudentDAO.class)

  public class StudentDAOBean implements StudentDAO {



   //===================================================

   //injection EntityManager object

   //unitName="test" here "test" from persistence.xml unit name

   @PersistenceContext(unitName="test")

   protected EntityManager em;

 

   public List getStudentByName(String _name) {

    List studentList = null;

  

    //===============================================

    //invoke the named query

    Query query = em.createQuery("from Student as s where s.name=?1 order by s.id asc");

    query.setParameter(1, _name);

  

    //===============================================

    //execute query

    studentList = query.getResultList();

  

    return studentList;

   }



   public List getStudentList() {

    List studentList = null;

    //===============================================

    //invoke the named query

    Query query = em.createQuery("from Student as s order by s.id asc");



    //===============================================

    //execute query

    studentList = query.getResultList();

  

    return studentList;

   }

  }



1.6 实现测试业务类客户端代码:StudentClient.java

  package com.cootme.blogic;



  import java.util.List;

  import java.util.Iterator;

  import java.util.Properties;



  import javax.naming.InitialContext;

  import javax.naming.NamingException;



  import com.cootme.ejb3.entity.Student;

  import com.cootme.ejb3.seesion.student.StudentDAO;



  public class StudentClient {

   //======================================================

   Properties props = null;

   InitialContext ctx = null;

   private void init(){

    if(props == null){

     props = new Properties();

     props.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");

     props.setProperty("java.naming.provider.url", "localhost:1099");

    }

    try{

     if(ctx == null){

      ctx = new InitialContext(props);

     }

    }catch(NamingException ne){

     System.out.println("==>COOTME-1: Naming exception");

     ne.printStackTrace();

    }

   }

   public void getStudentByName(String _name){

    List studentList = null;

    try{

     init();

     StudentDAO dao = (StudentDAO)ctx.lookup("StudentDAOBean/remote");

     studentList = dao.getStudentByName(_name);

   

     if(studentList != null){

      Iterator i = studentList.iterator();

      while(i.hasNext()){

       Student s = (Student)i.next();

       System.out.println("=========== Student table datas ===========");   

       System.out.println(s.getId() + " " + s.getName() + " " + s.getSex() + " " +

         s.getAge() + " " + s.getMobile() + " " + s.getEmail());

       System.out.println("===========================================");

      }

     }

    }catch(NamingException ne){

     System.out.println("==>COOTME-2: Naming exception");

     ne.printStackTrace();

    }

   }

 

   public void getStudents(){

    List studentList = null;

    try{

     init();

     StudentDAO dao = (StudentDAO)ctx.lookup("StudentDAOBean/remote");

     studentList = dao.getStudentList();

   

     if(studentList != null){

      Iterator i = studentList.iterator();

      while(i.hasNext()){

       Student s = (Student)i.next();

       System.out.println("=========== Student table datas ===========");   

       System.out.println(s.getId() + " " + s.getName() + " " + s.getSex() + " " +

         s.getAge() + " " + s.getMobile() + " " + s.getEmail());

       System.out.println("===========================================");

      }

     }

    }catch(NamingException ne){

     System.out.println("==>COOTME-2: Naming exception");

     ne.printStackTrace();

    }

   }

  }



1.7 测试应用的web页面代码：index.jsp

  <%@ page language="java" contentType="text/html; charset=ISO-8859-1"

      pageEncoding="ISO-8859-1"%>

  <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

  <%@page import="com.cootme.blogic.StudentClient"%>

  <html>

  <head>

  <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">

  <title>Hello, COOTME</title>

  </head>

  <body>

  <h1>Hello</h1>

  <%

   StudentClient sc = new StudentClient();

   sc.getStudentByName("geyou");

   sc.getStudents();

  %>

  </body>

  </html>



1.8 编译、发布到jboss服务器中：build.xml

  <?xml version="1.0"?>



  <!-- ======================================================================= -->

  <!-- EJB3 WebProject build file                                                       -->

  <!-- ======================================================================= -->



  <project name="WebProject" default="ejbjar" basedir="..">



   <property environment="env" />

   <property name="app.dir" value="${basedir}/WebProject" />

   <property name="src.dir" value="${app.dir}/src" />

   <property name="jboss.home" value="${env.JBOSS_HOME}" />

   <property name="jboss.server.config" value="default" />

   <property name="build.dir" value="${app.dir}/build" />

   <property name="build.classes.dir" value="${build.dir}/classes" />



   <!-- Build classpath -->

   <path id="build.classpath">

    <fileset dir="${basedir}/ejbjars">

     <include name="*.jar" />

    </fileset>

    <pathelement location="${build.classes.dir}" />

   </path>



   <!-- =================================================================== -->

   <!-- Prepares the build directory                                        -->

   <!-- =================================================================== -->

   <target name="prepare">

    <mkdir dir="${build.dir}" />

    <mkdir dir="${build.classes.dir}" />

   </target>



   <!-- =================================================================== -->

   <!-- Compiles the source code                                            -->

   <!-- =================================================================== -->

   <target name="compile" depends="prepare" description="编绎">

    <javac srcdir="${src.dir}" destdir="${build.classes.dir}" debug="on" deprecation="on" optimize="off" includes="**">

     <classpath refid="build.classpath" />

    </javac>

   </target>



   <target name="ejbjar" depends="compile,createwar" description="创建EJB发布包">

    <jar jarfile="${app.dir}/cootmeejb3.jar">

     <fileset dir="${build.classes.dir}">

      <include name="**/*.class" />

     </fileset>

     <metainf dir="${src.dir}/META-INF">

      <include name="**" />

     </metainf>

    </jar>

   </target>



   <target name="createwar" description="创建WAR包">

    <jar jarfile="${app.dir}/WebProject.war">

     <fileset dir="${app.dir}/WebContent"/>

    </jar>

   </target>

   <target name="deploy" depends="ejbjar" description="发布到JBOSS">

    <copy file="${app.dir}/cootmeejb3.jar" todir="${jboss.home}/server/${jboss.server.config}/deploy" />

    <copy file="${app.dir}/WebProject.war" todir="${jboss.home}/server/${jboss.server.config}/deploy" />

   </target>



   <!-- =================================================================== -->

   <!-- Cleans up generated stuff                                           -->

   <!-- =================================================================== -->

   <target name="clean">

    <delete dir="${build.dir}" />

    <delete file="${jboss.home}/server/${jboss.server.config}/deploy/WebProject.jar" />

   </target>



  </project>



1.9 在dos或者eclipse开发环境下运行build.xml，即可自动部署到服务器中

  部署成功，在jboss的dos窗口中可以到如下的信息：

  14:06:22,343 INFO  [JmxKernelAbstraction] installing MBean: jboss.j2ee:jar=cootm

  eejb3.jar,name=StudentDAOBean,service=EJB3 with dependencies:

  14:06:22,343 INFO  [JmxKernelAbstraction]       persistence.units:jar=cootmeejb3

  .jar,unitName=test

  14:06:22,363 INFO  [EJBContainer] STARTED EJB: com.cootme.ejb3.seesion.student.b

  ean.StudentDAOBean ejbName: StudentDAOBean

  14:06:22,373 INFO  [EJB3Deployer] Deployed: file:/D:/MySoft/jboss-4.2.0.GA/serve

  r/default/deploy/cootmeejb3.jar

  14:06:22,453 INFO  [TomcatDeployer] deploy, ctxPath=/cootmeweb, warUrl=.../tmp/d

  eploy/tmp57731WebProject-exp.war/



1.10 打开IE浏览器输入以下地址：http://localhost:8080/cootmeweb/

  即可看到jboss后台的dos窗口的输出:

  13:55:11,368 INFO  [STDOUT] =========== Student table datas ===========

  13:55:11,368 INFO  [STDOUT] 1 geyou NA 28 13426445816 [email protected]

  13:55:11,368 INFO  [STDOUT] ===========================================

  13:55:11,388 INFO  [STDOUT] =========== Student table datas ===========

  13:55:11,388 INFO  [STDOUT] 1 geyou NA 28 13426445816 [email protected]

  13:55:11,388 INFO  [STDOUT] ===========================================

  13:55:11,388 INFO  [STDOUT] =========== Student table datas ===========

  13:55:11,388 INFO  [STDOUT] 2 cootme NA 28 13426445816 [email protected]

  13:55:11,388 INFO  [STDOUT] ===========================================

  13:55:11,388 INFO  [STDOUT] =========== Student table datas ===========

  13:55:11,388 INFO  [STDOUT] 3 HFH NA 28 13426445816 [email protected]

  13:55:11,388 INFO  [STDOUT] ===========================================

  到此全部的ejb3的entity bean和session bean的开发全部结束，可以好好轻松一下了，呵呵...



注意：在以上的开发之前，需要准备好MySQL数据库，本人用的是MySQL5,使用的是test数据库实例，

   其中有一张表名为：student,结构如下：

   DROP TABLE `test`.`student`;

 

   CREATE TABLE `test`.`student` (

    `id` INT,

    `name` VARCHAR(20),

    `age` INT,

    `sex` CHAR(2),

    `mobile` VARCHAR(15),

    `email` VARCHAR(50)

   ) ENGINE=InnoDB;

   请大家对应自己的表结构。

本文引用自http://blog.csdn.net/ThirdDimension/archive/2008/06/26/2589741.aspx,  感谢 第三空间的朋友