基于Annotation的Struts2.0+Hibernate3.3+Spring2.5整合开发 (1)
package?com.rong.entity;

import?javax.persistence.Column;
import?javax.persistence.Entity;
import?javax.persistence.GeneratedValue;
import?javax.persistence.GenerationType;
import?javax.persistence.Id;
import?javax.persistence.Table;

@Entity
@Table(name="tb_user")
public?class?User?{
????
????@Id????@GeneratedValue(strategy=GenerationType.IDENTITY)
????private?int?id;
????
????@Column(name="username",?length=15)
????private?String?username;
????
????@Column(name="password",?length=15)
????private?String?password;
????
????public?int?getId()?{
????????return?id;
????}
????public?void?setId(int?id)?{
????????this.id?=?id;
????}
????public?String?getUsername()?{
????????return?username;
????}
????public?void?setUsername(String?username)?{
????????this.username?=?username;
????}
????public?String?getPassword()?{
????????return?password;
????}
????public?void?setPassword(String?password)?{
????????this.password?=?password;
????}

}

????????简单解释一下吧：
????????@Entity定义User类为实体类，@Id定义该属性对应的列为主键，@GeneratedValue(strategy=GenerationType.IDENTITY)定义主键生成策略为Indentity，适用于MySQL和MS SQL等数据库。@Column(name="username", length=15)定义列名和取值长度。
????????应该不难的，更多有关Hibernate的注解，请下载并参考我整理的Hibernate Annotation帮助文档 /Files/rongxh7/hibernateAannotations.rar?。慢慢学吧！
????????
????????当然，必要的XML配置文件还是要有的：

<?xml?version='1.0'?encoding='utf-8'?>
<!DOCTYPE?hibernate-configuration?PUBLIC
????????"-//Hibernate/Hibernate?Configuration?DTD?3.0//EN"
????????"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

????<session-factory>

????????<!--?Database?connection?settings?-->
????????<property?name="connection.driver_class">com.mysql.jdbc.Driver</property>
????????<property?name="connection.url">jdbc:mysql://localhost:3306/ssh_annotation</property>
????????<property?name="connection.username">root</property>
????????<property?name="connection.password">root</property>

????????<!--?数据库言?-->
????????<property?name="dialect">org.hibernate.dialect.MySQLDialect</property>
????????
????????<!--?将Session扔到线程里去处理?-->
????????<property?name="current_session_context_class">thread</property>

????????<!--?在控制台打印SQL语句?-->
????????<property?name="show_sql">true</property>

????????<!--?自动把实体类与属性映射成数据库中的表与列?-->
????????<property?name="hbm2ddl.auto">update</property>
?????????
????????<!--??
????????<mapping?resource="com/rong/entity/User.hbm.xml"/>
?????????-->
?????????
?????????<!--?在Hibernate中注册User实体类,区别于上面注释掉的resource写法?-->
?????????<mapping?class="com.rong.entity.User"/>

????</session-factory>

</hibernate-configuration>

????????到这里，我们可以运行Tomcat，Hibernate会根据hbm2ddl.auto自动地把实体类与属性转变成数据库中的表与列。但这一步，要事先在数据库中建立一个名为"ssh_annotation"的空数据库。好了，看一下，你的数据库中是否有"tb_user"的表生成了？！
????????接下来，我们来开发一个包装器类，取名HibernateUtil，代码如下：

package?test.rong.hibernate;

import?org.hibernate.SessionFactory;
import?org.hibernate.cfg.AnnotationConfiguration;

public?class?HibernateUtil?{
????
????private?static?final?SessionFactory?sessionFactory;

????static?{
????????try?{
????????????//用xxx.hbm.xml形式配置实体映射
????????????//sessionFactory?=?new?Configuration().configure().buildSessionFactory();
????????????//用Annotation形式配置实体映射
????????????sessionFactory?=?new?AnnotationConfiguration().configure().buildSessionFactory();
????????}?catch?(Throwable?ex)?{
????????????System.err.println("Initial?SessionFactory?creation?failed."?+?ex);
????????????throw?new?ExceptionInInitializerError(ex);
????????}
????}

????public?static?SessionFactory?getSessionFactory()?{
????????return?sessionFactory;
????}

}

????????学过Hibernate的朋友们，应该对这个类不陌生吧。在此，我就不多解释啦，注意一下我注释的地方就行。下面，我们来进行测试，下载最新版本的Junit4.5.jar，试一下感觉如何。当然，旧版本的应该也没问题的啦！写测试代码如下：????

package?test.rong.hibernate;

import?java.util.Iterator;
import?java.util.List;
import?org.hibernate.Query;
import?org.hibernate.Session;
import?org.junit.Before;
import?org.junit.Test;
import?com.rong.entity.User;

public?class?EntityTest?{
????
????private?Session?session;
????
????@Before
????public?void?initSession(){
????????this.session?=?HibernateUtil.getSessionFactory().getCurrentSession();
????}
????
????@Test????//测试添加用户
????public?void?testSave(){
????????session.beginTransaction();
????????User?user?=?new?User();
????????user.setUsername("rongxh7");
????????user.setPassword("blogjava");
????????session.save(user);
????????session.getTransaction().commit();
????}
????
????@Test????//测试查询用户列表
????@SuppressWarnings("unchecked")
????public?void?testQuery(){
????????session.beginTransaction();
????????Query?query?=?session.createQuery("from?User?u");
????????List<User>?users?=?query.list();
????????for(Iterator<User>?it?=?users.iterator()?;?it.hasNext()?;?){
????????????User?user?=?it.next();
????????????System.out.println("username?=?"?+?user.getUsername());
????????}
????????session.beginTransaction().commit();
????}
????
????@Test????//测试查询单个用户
????public?void?testGet(){
????????session.beginTransaction();
????????User?user?=?(User)session.get(User.class,?1);
????????System.out.println("username?=?"?+?user.getUsername());
????????session.getTransaction().commit();
????}
????
????@Test????//测试查询修改用户
????public?void?testUpdate(){
????????session.beginTransaction();
????????User?user?=?(User)session.load(User.class,?1);
????????user.setPassword("hello?blogjava");
????????session.update(user);
????????session.getTransaction().commit();
????}
????
????@Test????//测试删除用户
????public?void?testDelete(){
????????session.beginTransaction();
????????session.delete(session.load(User.class,?1));
????????session.getTransaction().commit();
????}

}

????????
????????到此，我们的Hibernate Annotation开发完成了。你成功了没？如果有什么问题，请回复，我尽力为你解答！好，第一阶段暂告一段落。不要忘记，我们是要做的是基于Annotatioln的SSH整合开发，让我们一起期待下一阶段吧！
????????(*^-^*) 本文原创，转载请注明出处，?http://www.blogjava.net/rongxh7谢谢! (*^-^*)

本文原创，转载请注明出处，谢谢！http://www.blogjava.net/rongxh7（心梦帆影JavaEE技术博客）