之前一直用spring jdbc，觉得是最简洁，最人畜无害的。但是，sql写的我tmd有点烦了，于是今天开始转向hibernate。之前学过一点，但是工作中从来没用过，先大概了解一下近两年来hibernate的发展，其他的也没注意，就是hibernate也支持注解了（可能是我孤陋寡闻了 - -！）也加了对JPA的实现，了解的过程中又发现Spring Data这货。一点点来吧，本文主要是试用一下从基础的Hibernate xml配置，再到annotation，再到与spring集成，再到spring data，再到。。。。。

注：本文不会为你一一讲解怎么配置、怎么用，就是想展示一下代码结构。如果想入门请另google。

完整代码见：

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新建Maven工程，假设是用户管理模块，目录结构：

User.java

package com.yaolifei.test.user.domain;import java.util.Date;public class User {	private Integer id;	private String name;	private Date birthday;	public Integer getId() {		return id;	}	public void setId(Integer id) {		this.id = id;	}	public String getName() {		return name;	}	public void setName(String name) {		this.name = name;	}	public Date getBirthday() {		return birthday;	}	public void setBirthday(Date birthday) {		this.birthday = birthday;	}}

UserService.java

package com.yaolifei.test.user.service;import java.util.List;import com.yaolifei.test.user.domain.User;public interface UserService {	User getById(Integer id);	List
    
      getAll();	void save(User user);	void update(User user);	void remove(User user);}
    

假设没有一点业务逻辑，就纯粹的调用Dao UserServiceImpl.java

package com.yaolifei.test.user.service;import java.util.List;import com.yaolifei.test.user.dao.UserDao;import com.yaolifei.test.user.domain.User;public class UserServiceImpl implements UserService {	private UserDao userDao;	@Override	public User getById(Integer id) {		return userDao.getById(id);	}	@Override	public List
    
      getAll() {		return userDao.getAll();	}	@Override	public void save(User user) {		userDao.save(user);	}	@Override	public void update(User user) {		userDao.update(user);	}	@Override	public void remove(User user) {		userDao.remove(user);	}	}
    

所以UserDao和UserService差不多是一样的 UserDao.java

package com.yaolifei.test.user.dao;import java.util.List;import com.yaolifei.test.user.domain.User;public interface UserDao {		User getById(Integer id);	List
    
      getAll();	void save(User user);	void update(User user);	void remove(User user);}
    

重点是UserDaoImpl的实现 UserDaoImpl.java

package com.yaolifei.test.user.dao;import java.util.List;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.SessionFactory;import com.yaolifei.test.user.domain.User;import com.yaolifei.test.util.HibernateUtil;public class UserDaoImpl implements UserDao {	@Override	public User getById(Integer id) {		SessionFactory sessionFactory = HibernateUtil.getSessionFactory();		Session session = sessionFactory.openSession();		session.beginTransaction();		User user = (User) session.get(User.class, id);		session.getTransaction().commit();		session.close();		return user;	}	@Override	public List
    
      getAll() {		SessionFactory sessionFactory = HibernateUtil.getSessionFactory();		Session session = sessionFactory.openSession();		session.beginTransaction();		Query query = session.createQuery("from User");		List
     
       list = query.list();		session.getTransaction().commit();		session.close();		return list;	}	@Override	public void save(User user) {		SessionFactory sessionFactory = HibernateUtil.getSessionFactory();		Session session = sessionFactory.openSession();		session.beginTransaction();		session.save(user);		session.getTransaction().commit();		session.close();	}	@Override	public void update(User user) {		SessionFactory sessionFactory = HibernateUtil.getSessionFactory();		Session session = sessionFactory.openSession();		session.beginTransaction();		session.update(user);		session.getTransaction().commit();		session.close();	}	@Override	public void remove(User user) {		SessionFactory sessionFactory = HibernateUtil.getSessionFactory();		Session session = sessionFactory.openSession();		session.beginTransaction();		session.delete(user);		session.getTransaction().commit();		session.close();	}		}
     
    

可以看出

SessionFactory sessionFactory = HibernateUtil.getSessionFactory();Session session = sessionFactory.openSession();session.beginTransaction();// ..................session.getTransaction().commit();session.close();

这个是模板代码，可以封装下。（不过我相信spring已经做了）

HibernateUtil提供创建单例SessionFactory的方法HibernateUtil.java

package com.yaolifei.test.util;import org.hibernate.SessionFactory;import org.hibernate.cfg.Configuration;public class HibernateUtil {		private final static SessionFactory sessionFactory = buildSessionFactory();		private static SessionFactory buildSessionFactory() {		Configuration cfg = new Configuration();		cfg.configure("hibernate.cfg.xml");				return cfg.buildSessionFactory();	}				public static SessionFactory getSessionFactory() {		return sessionFactory;	}	}

下面看下Hibernate的配置：

    
    	
     		
      		
      
       com.mysql.jdbc.Driver
      		
      
       jdbc:mysql://localhost/test
      		
      
       root
      		
      
       880716
      		
      		
      
       1
      				
      		
      
       org.hibernate.dialect.MySQL5Dialect
      				
      		
      
       thread
      				
      		
      
       org.hibernate.cache.NoCacheProvider
      		
      		
      
       true
      		
      		
      
       update
      		
      	
     
    

还有映射文件：

测试类 UserServiceTest.java

package com.yaolifei.test.user.service;import static org.junit.Assert.*;import java.util.Calendar;import java.util.List;import org.junit.Test;import com.yaolifei.test.user.domain.User;public class UserServiceTest {	private UserService userService = new UserServiceImpl();		@Test	public void getById() {		Integer id = 1;		User user = userService.getById(id);		assertEquals("yaolifei", user.getName());	}	@Test	public void getAll() {		List
    
      user = userService.getAll();		assertEquals(1, user.size());	}	@Test	public void save() {		User user = new User();		user.setName("yaolifei");		Calendar c = Calendar.getInstance();		c.set(1988, 7-1, 16);		user.setBirthday(c.getTime());				userService.save(user);	}	@Test	public void update() {		User user = userService.getById(1);		user.setName("yaolf");		userService.update(user);				User newUser = userService.getById(1);		assertEquals(newUser.getName(), "yaolf");	}	@Test	public void remove() {		User user = userService.getById(1);		userService.remove(user);				User newUser = userService.getById(1);		assertNull(newUser);	}	}
    

 下面来跑测试 首先是增加一个User

控制台出现一条sql语句：INFO: HHH000232: Schema update completeHibernate: insert into SYS_USER (USER_NAME, USER_BIRTHDAY) values (?, ?)

因为id是自动生成的，所以没有插入，看下表里的数据：

自动生成了一个sys_user表，看下表结构： 再看下表数据： 下面可以一一测试一下其他代码。这边就不一一贴结果了

测试中。。。。

全部成功。