1、编写POJO映射类User.java
public class User implements Serializable{
private int id;
private String name;
private String password;
private String type;
public User() {
}
public 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;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
}
2、编写映射类User.hbm.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="org.hibernate.entity.User" table="user">
<id name="id" type="java.lang.Integer" column="USER_ID">
<generator class="increment"></generator>
</id>
<property name="name" type="java.lang.String" column="NAME" length="20"></property>
<property name="password" type="java.lang.String" column="PASSWORD" length="12"></property>
<property name="type" type="java.lang.String" column="TYPE" length="6"></property>
</class>
</hibernate-mapping>
3、编写hibernate.cfg.xml配置文件
<?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>
<!--数据库连接设置 -->
<!-- 配置数据库JDBC驱动 -->
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<!-- 配置数据库连接URL -->
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/mysqldb</property>
<!-- 配置数据库用户名 -->
<property name="hibernate.connection.username">root</property>
<!-- 配置数据库连接密码 -->
<property name="hibernate.connection.password">123</property>
<!-- 配置JDBC内置连接池 -->
<property name="connection.pool_size">1</property>
<!-- 配置数据库方言 -->
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- 输出运行时生成的SQL语句 -->
<property name="show_sql">true</property>
<!-- 列出所有的映射文件 -->
<mapping resource="org/hibernate/entity/User.hbm.xml"/>
</session-factory>
</hibernate-configuration>
4、编写辅助工具类HibernateUtil.java
public class HibernateUtil {
private static SessionFactory sessionFactory;
//创建线程局部变量threadLocal,用来保存hibernate的Session
private static final ThreadLocal<Session> threadLocal=new ThreadLocal<Session>();
//使用静态代码块初始化hibernate
static{
try {
//读取配置文件hibernate.cfg.xml
Configuration cfg=new Configuration().configure();
//创建sessionFactory
sessionFactory=cfg.buildSessionFactory();
} catch (Throwable e) {
throw new ExceptionInInitializerError(e);
}
}
//获取sessionFactory实例
public static SessionFactory getSessionFactory(){
return sessionFactory;
}
//获得threadLocal对象管理的session实例
public static Session getSession(){
Session session=(Session)threadLocal.get();
if (session==null||!session.isOpen()) {
if (sessionFactory==null) {
rebuildSessionFactory();
}
//通过sessionFactory对象创建Session对象
session=(sessionFactory!=null)?sessionFactory.openSession():null;
//将新打开的Session实例保存到线程局部变量threadLocal中
threadLocal.set(session);
}
return session;
}
//关闭Session实例
public static void closeSession() {
//从线程局部变量threadLocal中获取之前存入的session实例
Session session=(Session) threadLocal.get();
threadLocal.set(null);
if (session!=null) {
session.close();
}
}
//重建sessionFactory
public static void rebuildSessionFactory() {
try {
//读取配置文件hibernate.cfg.xml
Configuration cfg=new Configuration().configure("/hibernate.cfg.xml");
//创建sessionFactory
sessionFactory=cfg.buildSessionFactory();
} catch (Exception e) {
System.err.println("Error Creating SessionFactory");
e.printStackTrace();
}
}
//关闭缓存和连接池
public static void shutdown(){
getSessionFactory().close();
}
}
5、编写DAO接口UserDAO.java
public interface UserDAO {
void save(User user);//添加用户
User findById(int id);//根据用户标识查找制定用户
void delete(User user);//删除用户
void update(User user);//修改用户信息
}
6、编写DAO层实现类UserDAOImpl.java
public class UserDAOImpl implements UserDAO{
//添加用户
@Override
public void save(User user) {
Session session=HibernateUtil.getSession();//生成Session实例
Transaction tx=session.beginTransaction();//创建Transaction实例
try {
session.save(user);//使用session的save方法将持久化对象保存到数据库
tx.commit();//提交事务
} catch (Exception e) {
e.printStackTrace();
tx.rollback();//回滚事务
}finally {
HibernateUtil.closeSession();//关闭session实例
}
}
//根据用户标识查找制定用户
@Override
public User findById(int id) {
User user=null;
Session session=HibernateUtil.getSession();
Transaction tx=session.beginTransaction();
try {
user=(User)session.get(User.class, id);
tx.commit();
} catch (Exception e) {
e.printStackTrace();
tx.rollback();
}finally {
HibernateUtil.closeSession();
}
return user;
}
//删除用户
@Override
public void delete(User user) {
Session session=HibernateUtil.getSession();
Transaction tx=session.beginTransaction();
try {
session.delete(user);
tx.commit();
} catch (Exception e) {
e.printStackTrace();
tx.rollback();
}finally {
HibernateUtil.closeSession();
}
}
//修改用户信息
@Override
public void update(User user) {
Session session=HibernateUtil.getSession();
Transaction tx=session.beginTransaction();
try {
session.update(user);
tx.commit();
} catch (Exception e) {
e.printStackTrace();
tx.rollback();
}finally {
HibernateUtil.closeSession();
}
}
}
7、编写测试类UserTest.java
public class UserTest {
@Before //@Before 注解表明setUp()方法为初始化方法
public void setUp() throws Exception{}
//测试方法
@Test //使用@Test注释表明testSave方法为一个测试方法
public void testSave() {
UserDAO userDAO=new UserDAOImpl();
try {
User user=new User();
user.setId(20);
user.setName("王五");
user.setPassword("2223");
user.setType("admin");
userDAO.save(user);//调用save方法将User对象存入数据库
} catch (Exception e) {
e.printStackTrace();
}
}
}