Dao层系列-1-Hibernate上手
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：http://git.oschina.net/yaolifei/test/tree/master/test-hibernate
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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<User> 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<User> 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<User> 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<User> getAll() {
SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
Query query = session.createQuery("from User");
List<User> 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：
<?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/test</property> <property name="connection.username">root</property> <property name="connection.password">880716</property> <!-- JDBC connection pool (use the built-in) --> <property name="connection.pool_size">1</property> <!-- SQL dialect --> <property name="dialect">org.hibernate.dialect.MySQL5Dialect</property> <!-- Enable Hibernate's automatic session context management --> <property name="current_session_context_class">thread</property> <!-- Disable the second-level cache --> <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property> <!-- Echo all executed SQL to stdout --> <property name="show_sql">true</property> <!-- Drop and re-create the database schema on startup --> <property name="hbm2ddl.auto">update</property> <mapping resource="user.hbm.xml"/> </session-factory> </hibernate-configuration>还有映射文件：
<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.yaolifei.test.user.domain"> <class name="User" table="SYS_USER"> <id name="id" column="USER_ID"> <generator class="native"/> </id> <property name="name" column="USER_NAME"/> <property name="birthday" type="timestamp" column="USER_BIRTHDAY"/> </class> </hibernate-mapping>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> 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 complete Hibernate: 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。