EJB实现简单CRUD操作和生命周期探讨
环境
MyEclipse 8.6 + JBoss 6.0 + JDK 1.6.13 + EJB 3.0
问题
EJB实现简单CRUD操作和生命周期探讨
解决
1. 配置JBoss数据源
a) 数据源参考配置文件
jboss-6.0.0.Final/docs/examples/jca/**-ds.xml
b) 将配置文件放到站点根目录下
jboss-6.0.0.Final/server/default/deploy
c) 将connector加入站点
server/default/lib
d) 配置相关的参数
<jndi-name>MySqlDS</jndi-name>
<connection-url>jdbc:mysql://xxx:3306/xxx</connection-url>
<driver-class>com.mysql.jdbc.Driver</driver-class>
<user-name>xxx</user-name>
<password>xxx</password>
e) 启动JBoss
2. 创建数据库表
CREATE TABLE user( id int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT, name varchar(255) DEFAULT NULL, password varchar(255) DEFAULT NULL);
3. 编写实体Bean
User.java
package com.wgb.bean.entity;import java.io.Serializable;import javax.persistence.Entity;import javax.persistence.EntityListeners;import javax.persistence.Id;import com.wgb.bean.UserListener;/** * @className: User.java * @classDescription: * @function: * @author: Wentasy * @createTime: 2012-12-4 下午08:00:32 * @modifyTime: * @modifyReason: * @since: JDK 1.6 */@Entity@EntityListeners(UserListener.class)public class User implements Serializable{private int id;private String name;private String password;@Idpublic int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}
4. 创建对数据库进行操作的Session Bean
UserDao.java
package com.wgb.dao;import java.util.List;import com.wgb.bean.entity.User;/** * @className: UserDao.java * @classDescription: * @function: * @author: Wentasy * @createTime: 2012-12-4 下午08:02:46 * @modifyTime: * @modifyReason: * @since: JDK 1.6 */public interface UserDao {public List<User> getAllUser();public void insert(String name, String password);public void update(User user);public void delete(int id);public User getUser(int id);}
UserDaoImpl.java
package com.wgb.dao.impl;import java.util.Iterator;import java.util.List;import javax.ejb.Remote;import javax.ejb.Stateless;import javax.persistence.EntityManager;import javax.persistence.PersistenceContext;import javax.persistence.Query;import com.wgb.bean.entity.User;import com.wgb.dao.UserDao;/** * @className: UserDaoImpl.java * @classDescription: * @function: * @author: Wentasy * @createTime: 2012-12-4 下午08:03:25 * @modifyTime: * @modifyReason: * @since: JDK 1.6 */@Stateless@Remote ({UserDao.class})public class UserDaoImpl{@PersistenceContextprivate EntityManager em;@SuppressWarnings("unchecked")public List<User> getAllUser(){return em.createQuery("from User").getResultList();}public void insert(String name, String password){User user = new User();user.setName(name);user.setPassword(password);em.persist(user);}public void update(User user){em.merge(user);}public void delete(int id){em.remove(em.find(User.class, id));}public User getUser(int id){return em.find(User.class, id);}}
5. 编写对生命周期进行处理的Listener
UserListener.java
package com.wgb.bean;import javax.persistence.PostLoad;import javax.persistence.PostPersist;import javax.persistence.PostRemove;import javax.persistence.PostUpdate;import javax.persistence.PrePersist;import javax.persistence.PreRemove;import javax.persistence.PreUpdate;import com.wgb.bean.entity.User;/** * @className: UserListener.java * @classDescription: * @function: * @author: Wentasy * @createTime: 2012-12-11 下午07:44:00 * @modifyTime: * @modifyReason: * @since: JDK 1.6 */public class UserListener {@PrePersistpublic void prePersist(User user){System.out.println("prePersist called!");}@PostPersistpublic void postPersist(User user){System.out.println("postPersist called!");}@PreRemovepublic void preRemove(User user){System.out.println("preRemove called!");}@PostRemovepublic void postRemove(User user){System.out.println("postRemove called!");}@PreUpdatepublic void preUpdate(User user){System.out.println("preUpdate called!");}@PostUpdatepublic void postUpdate(User user){System.out.println("postUpdate called!");}@PostLoadpublic void postLoad(User user){System.out.println("postLoad called!");}}
6. 编写显示页面
index.jsp
<%@ page language="java" import="java.util.*,javax.naming.*,com.wgb.bean.*,com.wgb.bean.entity.*,com.wgb.dao.*,com.wgb.dao.impl.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <head> <base href="<%=basePath%>"> <title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--> </head> <body> <% try { //Remote //Properties props = new Properties(); //props.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory"); //props.setProperty("java.naming.provider.url", "localhost:1099"); //props.setProperty("java.naming.factory.url.pkgs", "org.jboss.naming"); //InitialContext ctx = new InitialContext(props); //HelloWorld helloworld = (HelloWorld) ctx.lookup("HelloWorldBean/remote"); //out.print(helloworld.sayHello("WGB")); //Local InitialContext ctx = new InitialContext(); //HelloWorld helloworld = (HelloWorld) ctx.lookup("HelloWorldBean/local"); //out.print(helloworld.sayHello("Wentasy")); //MyTimer t = (MyTimer)ctx.lookup("MyTimerBean/local"); //t.start(); UserDao userDao = (UserDao)ctx.lookup("UserDaoImpl/remote"); //插入数据 //userDao.insert("123", "123"); //19:55:05,370 INFO [STDOUT] prePersist called! //19:55:05,496 INFO [STDOUT] postPersist called! //更新数据 //User user = new User(); //user.setId(4);//user.setName("125");//user.setPassword("123"); //userDao.update(user); //19:55:26,769 INFO [STDOUT] postLoad called! //19:55:26,770 INFO [STDOUT] preUpdate called! //19:55:26,775 INFO [STDOUT] postUpdate called! //删除数据 //userDao.delete(6); //19:56:37,074 INFO [STDOUT] postLoad called! //19:56:37,078 INFO [STDOUT] preRemove called! //19:56:37,083 INFO [STDOUT] postRemove called! //得到所有数据 //for (User u : userDao.getAllUser()) { //out.println(u.getId() + " : " + u.getName() + "<br/>"); //} //19:57:28,970 INFO [STDOUT] postLoad called! //19:57:28,970 INFO [STDOUT] postLoad called! //19:57:28,970 INFO [STDOUT] postLoad called! //19:57:28,971 INFO [STDOUT] postLoad called! //得到单条数据 //User u = userDao.getUser(1); //out.println(u.getId() + " : " + u.getName() + " : " + u.getPassword()); //19:58:09,524 INFO [STDOUT] postLoad called! } catch (NamingException e) { e.printStackTrace(); } %> </body></html>
插入数据
调用prePersist和postPersist
更新数据
调用postLoad、preUpdate和postUpdate
删除数据
调用postLoad、preUpdate和postUpdate
得到所有数据
调用四次postLoad，因有四条数据
得到单条数据
调用一次postLoad