hibernate-MySQL配置文件及简单应用(CRUD)

1、引入hibernate  框架必须的jar 包，包括连接数据库的，自动生成的时候，为自动导入

2、hibernate 配置文件位于src 下，hibernate.cfg.xml   如下：

<?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><property name="connection.url">jdbc:mysql://127.0.0.1:3306/test</property>    <property name="connection.username">root</property>    <property name="connection.password">123</property>    <property name="connection.driver_class">com.mysql.jdbc.Driver</property>    <property name="dialect">org.hibernate.dialect.MySQLDialect</property>    <property name="show_sql">true</property><!--<property name="format_sql">true</property>--><mapping resource="User.hbm.xml"/>        </session-factory></hibernate-configuration>

3、编写polo类

package com.model;public class User {        private String id;        private String username;        private String password;    public String getId() {        return id;    }    public void setId(String 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;    }    public User() {    }}

4、对象映射文件  User.hbm.xml位于src 下：

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-mapping PUBLIC        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"><hibernate-mapping><class name="com.model.User" table="user"><!--设定主键的生成方式--><id name="id" column="id" type="string"><generator class="uuid"></generator></id><!--当类属性名称与数据库中字段名称一致时，column 可以省略--><property name="username" column="username" type="string"></property><property name="password" column="password" type="string"></property></class></hibernate-mapping>

5、将对象映射文件加入到hibernate配置文件中。

6、编写获取单实例的SessionFactory的 类 HibernateUtil.java

package com.util;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.cfg.Configuration;public class HibernateUtil {private static SessionFactory sessionFactory;static {try {//加载类的时候获取sessionFactorysessionFactory = new Configuration().configure().buildSessionFactory(); } catch(Exception e) {e.printStackTrace();}}public static Session getSession() {return sessionFactory.openSession();}public static void closeSession(Session session) {session.close();}}

7、编写 crud 的测试代码如下：

package com.test;import java.util.Iterator;import java.util.List;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.Transaction;import com.model.User;import com.util.HibernateUtil;public class HibernateTest {public static void main(String[] args) {User user = new User();//user.setId(100);user.setUsername("test4");user.setPassword("test4");save(user);//queryAll();//query("402880ea40478f420140478f46890001");//deleteAll();deleteAll2();} //插入public static void save(User user) {Session session = HibernateUtil.getSession();Transaction tx = null;try {     tx = session.beginTransaction();     String id = (String) session.save(user);     System.out.println(id);     tx.commit(); } catch (Exception e) {     if (tx!=null) tx.rollback();     e.printStackTrace(); } finally { HibernateUtil.closeSession(session); }}//遍历public static void queryAll() {Session session = HibernateUtil.getSession();//User 是类名 而不是表名Query query = session.createQuery("from User as u order by u.username asc");List<User> list = query.list();for(int i=0; i<list.size(); i++) {User user = list.get(i);System.out.print(user.getId() + "\t");System.out.print(user.getUsername() + "\t");System.out.println(user.getPassword());}}//删除public static void delete(String id) {Session session = HibernateUtil.getSession();Transaction tx = null;try {tx = session.beginTransaction();User user = (User) session.get(User.class, id);session.delete(user);tx.commit();} catch(Exception e) {  if (tx!=null) tx.rollback();     e.printStackTrace();} finally {HibernateUtil.closeSession(session);}}//查询public static void query(String id) {Session  session = HibernateUtil.getSession();User user = (User)session.get(User.class, id);System.out.println(user.getId());System.out.println(user.getUsername());System.out.println(user.getPassword());HibernateUtil.closeSession(session);}//删除全部public static void deleteAll() {Session session = HibernateUtil.getSession();Transaction tx = null;try {tx = session.beginTransaction();Query query = session.createQuery("from User");//按需加载 延迟加载  只返回id 然后根据需要再次查询，要求session 必须是打开的。Iterator<User> iter = query.iterate();while(iter.hasNext()) {session.delete(iter.next());}tx.commit();} catch(Exception e) {if(null != tx) tx.rollback();e.printStackTrace();} finally {HibernateUtil.closeSession(session);}}//删除全部2public static void deleteAll2() {Session session = HibernateUtil.getSession();Transaction tx = null;try {tx = session.beginTransaction();Query query = session.createQuery("from User");//返回全部的实体所有字段List<User> list = (List<User>)query.list();Iterator<User> iter = (Iterator<User>)list.iterator();while(iter.hasNext()) {session.delete(iter.next());}tx.commit();} catch(Exception e) {if(null != tx) tx.rollback();e.printStackTrace();} finally {HibernateUtil.closeSession(session);}}}