我用的是 mysql 数据库, EJB3.0 相对于2.0 变化蛮大的，真的是迫于 Spring+Hibernate 的逼式，ejb 3.0 已经出现几年了，自从她轻装上阵，也不知道现在的应用情况如何，不过本人认为， ejb 3.0 是很有市场的。它的简洁和方便无疑是程序员的最佳选择！

1. 配置 JBOSS 数据源：
如果你用默认的数据源就不需要这么改动，默认的是 Hsqldb。为了换成 mysql，而且把数据源的 JNDI 改成自己的名字，你需要如下配置：
一、拷贝驱动
我启动的是 default !

所以请保证JBOSS_INSTALL\server\default\lib下面有mysql jdbc driver

二、修改 JBOSS 配置文件

1、将文件JBOSS_INSTALL/docs/examples/jca/mysql-ds.xml拷贝到JBOSS_INSTALL\server\default\deploy下
面

修改如下：



MySqlDS

jdbc:mysql://localhost:3306/jbossdb

com.mysql.jdbc.Driver

root

123


2、将文件JBOSS_INSTALL/docs/examples/jms/mysql-jdbc2-service.xml拷贝到
JBOSS_INSTALL/server/default/deploy/jms下


修改如下：




name="jboss.mq:service=PersistenceManager">

name="ConnectionManager">jboss.jca:service=DataSourceBinding,name=MySqlDS







另外这个文件71行修改：

CREATE_TX_TABLE = CREATE TABLE JMS_TRANSACTIONS ( TXID INTEGER PRIMARY KEY NOT
NULL )



3、修改JBOSS_INSTALL/server/default/conf/standardjaws.xml如下：



java:/MysqlDS



mySQL


4、修改JBOSS_INSTALL/server/default/deploy/jms/hsqldb-jdbc-state-service.xml如下：


name="ConnectionManager">jboss.jca:service=DataSourceBinding,name=MysqlDS


5、修改JBOSS_INSTALL/server/default/deploy/ejb-deployer.xml如下：


name="jboss.ejb:service=EJBTimerService,persistencePolicy=database">



jboss.jca:service=DataSourceBinding,name=MysqlDS



name="DatabasePersistencePlugin">org.jboss.ejb.txtimer.GeneralPurposeDatabasePersistencePlugin




6、修改JBOSS_INSTALL/server/default/config/ standardjbosscmp-jdbc.xml如下：


java:/MysqlDS


7、修改JBOSS_INSTALL/server/default/deploy/ uuid-key-generator.sar下面的META-INF下面jboss-service.xml如
下：




jboss.jca:service=DataSourceBinding,name=MysqlDS





好了数据源配置方面已经完成！可以开始动手开发了！

2.MyEclipse6 开发 EntityBean

persistence.xml 配置文件



xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
version="1.0">

java:/MysqlDS

//create-drop 如果有表结构可以换成 update！
//相关详细内容请看书



3.PersonDAO 接口


import java.util.Date;
import java.util.List;

import org.jpa.test.Person;

public interface PersonDAO {
public boolean insertPerson(String name, boolean sex, short age,
Date birthday);

public String getPersonNameByID(int personid);

public boolean updatePerson(Person person);

public Person getPersonByID(int personid);

public List getPersonList(int max, int whichpage);
}

4.PersonDAOBean 无状态的会话Bean





package org.jpa.dao;

import java.util.Date;
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 org.jpa.test.Person;

@Stateless
@Remote( { PersonDAO.class })
public class PersonDAOBean implements PersonDAO {
@PersistenceContext
protected EntityManager em;

public String getPersonNameByID(int personid) {
Person person = em.find(Person.class, Integer.valueOf(personid));
return person.getName();
}

public boolean insertPerson(String name, boolean sex, short age,
Date birthday) {
try {
Person person = new Person();
person.setName(name);
person.setSex(sex);
person.setAge(Short.valueOf(age));
person.setBirthday(birthday);
em.persist(person);
} catch (Exception e) {
e.printStackTrace();
return false;
}
return true;
}

public Person getPersonByID(int personid) {
return em.find(Person.class, Integer.valueOf(personid));
}

public boolean updatePerson(Person person) {
try {
em.merge(person);
} catch (Exception e) {
e.printStackTrace();
return false;
}
return true;
}

public List getPersonList(int max, int whichpage) {
try {
int index = (whichpage - 1) * max;
Query query = em.createQuery("from Person p order by personid asc");
List list = query.setMaxResults(max).setFirstResult(index)
.getResultList();
em.clear(); // 分离内存中受EntityManager管理的实体bean，让VM进行垃圾回收
return list;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
}
5.类似 Hibernate 中开发 POJO 一样开发 EntityBean，不同的就是把 ORM 的 mapping file 改用在 code 中加入注释，效果类似！如果你学习过 jdo,ojb,hibernate,ibatis 等等你很容易上手！



package org.jpa.test;

import java.io.Serializable;
import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

@SuppressWarnings("serial")
@Entity
@Table(name = "person")
public class Person implements Serializable {
private Integer personid;
private String name;
private boolean sex;
private Short age;
private Date birthday;

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
public Integer getPersonid() {
return personid;
}

public void setPersonid(Integer personid) {
this.personid = personid;
}

@Column(name = "PersonName", nullable = false, length = 32)
public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

@Column(nullable = false)
public boolean getSex() {
return sex;
}

public void setSex(boolean sex) {
this.sex = sex;
}

@Column(nullable = false)
public Short getAge() {
return age;
}

public void setAge(Short age) {
this.age = age;
}

@Temporal(value = TemporalType.DATE)
public Date getBirthday() {
return birthday;
}

public void setBirthday(Date birthday) {
this.birthday = birthday;
}
}





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