java之hibernate之crud

这篇文章主要讲解：

　　1>.对Hibernate使用的一些简单封装；

·　　2>.在单元测试中，使用Hibernate的封装的工具进行增删改查的测试

1.目录结构展示

2.代码展示

2.0 配置文件 hibernate.cfg.xml

<!DOCTYPE hibernate-configuration PUBLIC

    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"

    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

        <!-- 数据库连接信息 -->

        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>

        <!-- 默认 localhost:3306 -->

        <property name="connection.url">jdbc:mysql:///test</property>

        <property name="connection.username">root</property>

        <property name="connection.password">root</property>

        <!-- 通用配置 -->

        <!-- 方言：hibernate要支持多种数据库，根据不同数据库生成对应的sql语句

            告诉hibernate使用的什么数据库，以便生成对应数据库的sql

         -->

        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

        <!-- 打印sql语句 -->

        <property name="show_sql">true</property>

        <!-- 格式化sql -->

        <property name="format_sql">true</property>

        <!-- 映射信息  注意映射文件存放的是文档路径 需要用/ -->

        <mapping resource="cn/vincent/pojo/User.hbm.xml"/>

    </session-factory>

</hibernate-configuration>

2.1 pojo 类

User

package cn.vincent.pojo;

import java.io.Serializable;

public class User implements Serializable {

    private int  id;

    private String name;

    private int age;

    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 int getAge() {

        return age;

    }

    public void setAge(int age) {

        this.age = age;

    }

    @Override

    public int hashCode() {

        final int prime = 31;

        int result = 1;

        result = prime * result + age;

        result = prime * result + id;

        result = prime * result + ((name == null) ? 0 : name.hashCode());

        return result;

    }

    @Override

    public boolean equals(Object obj) {

        if (this == obj)

            return true;

        if (obj == null)

            return false;

        if (getClass() != obj.getClass())

            return false;

        User other = (User) obj;

        if (age != other.age)

            return false;

        if (id != other.id)

            return false;

        if (name == null) {

            if (other.name != null)

                return false;

        } else if (!name.equals(other.name))

            return false;

        return true;

    }

}

User.hbm.xml 即User的映射

<?xml version="1.0" encoding="UTF-8"?>

<!-- 映射文件的头文件和hibernate.cfg.xml的头文件不一样 -->

<!DOCTYPE hibernate-mapping PUBLIC

    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="cn.vincent.pojo">

    <class name="User" table="t_user">

        <id name="id" column="id" type="int">

            <generator class="native"></generator>

        </id>

        <property name="name" column="name" type="java.lang.String"/>

        <property name="age" column="age" type="int"/>

    </class>

</hibernate-mapping>

2.2 util 工具类

package cn.vincent.util;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.boot.registry.StandardServiceRegistryBuilder;

import org.hibernate.cfg.Configuration;

import org.hibernate.service.ServiceRegistry;

public class HibernateUtil {

    private static Configuration cfg;

    private static ServiceRegistry registry;

    private static SessionFactory factory;

    private static ThreadLocal<Session> session;

    static{

        //初始化

        cfg=new Configuration().configure();

        registry=new StandardServiceRegistryBuilder()

                    .applySettings(cfg.getProperties())

                    .build();

        factory=cfg.buildSessionFactory(registry);

        session=new ThreadLocal<>();

    }

    //获取连接

    public static Session getSession(){

        if(session.get()==null){

            session.set(factory.openSession());

        }

        return session.get();

    }

    //释放资源

    public static void close(){

        if(session.get()!=null){

            session.get().close();

            session.set(null);

        }

    }

}

2.3 单元测试

HibernateTest

package cn.vincent.hibernate;

import java.util.List;

import org.hibernate.Session;

import org.hibernate.Transaction;

import org.junit.Test;

import cn.vincent.pojo.User;

import cn.vincent.util.HibernateUtil;

public class HibernateTest {

    //根据id查询单个对象

        @Test

        public void testGetById(){

            Session session = HibernateUtil.getSession();

            User user=(User)session.get(User.class, 2);

            System.out.println(user.getId()+"----"+user.getName()+"----"+user.getAge());

            HibernateUtil.close();

        }

        //添加数据

        @Test

        public void testSave(){

            Session session=null;

            Transaction tx =null;

            try {

                session = HibernateUtil.getSession();

                User user= new User();

                user.setName("金庸");

                user.setAge(80);

                //开启事务

                tx = session.beginTransaction();

                //返回 被保存数据的id

                session.save(user);

                //提交事务

                tx.commit();

                System.out.println("保存数据成功");

            } catch (Exception e) {

                e.printStackTrace();

                //回滚事务

                if(tx!=null)

                    tx.rollback();

                System.out.println("保存数据失败");

            }finally{

                HibernateUtil.close();

            }

        }

        //删除数据

        @Test

        public void testDelete(){

            Session session=null;

            Transaction tx =null;

            try {

                session = HibernateUtil.getSession();

                //开启事务

                tx = session.beginTransaction();

                User user =(User)session.get(User.class, 4);

                session.delete(user);

                //提交事务

                tx.commit();

                System.out.println("删除数据成功");

            } catch (Exception e) {

                e.printStackTrace();

                //回滚事务

                if(tx!=null)

                    tx.rollback();

                System.out.println("删除数据失败");

            }finally{

                HibernateUtil.close();

            }

        }

        //更新

        @Test

        public void testUpdate(){

            Session session=null;

            Transaction tx =null;

            try {

                session = HibernateUtil.getSession();

                //开启事务

                tx = session.beginTransaction();

                User user =(User)session.get(User.class, 4);

                user.setName("本拉登");

                session.update(user);

                //提交事务

                tx.commit();

                System.out.println("更新数据成功");

            } catch (Exception e) {

                e.printStackTrace();

                //回滚事务

                if(tx!=null)

                    tx.rollback();

                System.out.println("更新数据失败");

            }finally{

                HibernateUtil.close();

            }

        }

        //查询所有

        @Test

        public void testFindAll(){

            Session session=null;

            try {

                session = HibernateUtil.getSession();

                List<User> list = session.createCriteria(User.class).list();

                for(User u:list){

                    System.out.println(u);

                }

            } catch (Exception e) {

                e.printStackTrace();

            }finally{

                HibernateUtil.close();

            }

        }

}

3.单元测试运行效果

运行单元测试

如下图：

巴特西

java之hibernate之crud

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