[Hibernate单表操作] 单表操作CRUD实例

一 常用方法

save

update

delete

get/load(查询单个记录)

 

二 测试代码

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.InputStream;

import java.io.OutputStream;

import java.sql.Blob;

import java.util.Date;

import org.hibernate.Hibernate;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

import org.hibernate.service.ServiceRegistry;

import org.hibernate.service.ServiceRegistryBuilder;

import org.junit.After;

import org.junit.Before;

import org.junit.Test;

//测试类

public class StudentsTest {

    

    private SessionFactory sessionFactory;

    private Session session;

    private Transaction transaction;

    @Before

    public void init(){

        // 创建配置对象   

        Configuration config = new Configuration().configure();

        //config.addClass(Students.class);

        // 创建服务注册对象

        ServiceRegistry serviceRegistery = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry();

        // 创建会话工厂对象

        sessionFactory = config.buildSessionFactory(serviceRegistery);

        // 创建会话对象

        session = sessionFactory.openSession();

        // 开启事务

        transaction = session.beginTransaction();

    }

    

    @After

    public void destory(){

        // 提交事务

        transaction.commit();

        // 关闭会话

        session.close();

        // 关闭会话工厂

        sessionFactory.close();

    }

    

    @Test

    public void testSaveStudents(){

        //Students s= new Students(1,"张三丰","男",new Date(),"武当山");

        Students s= new Students();

        s.setSname("张三丰");

        s.setGender("男");

        s.setBirthday(new Date());

        //s.setAddress("武当山");

        Address address = new Address("7232","125674323","湖北");

        s.setAddress(address);

        session.save(s);

    }

    

    @Test

    public void testGetStudents()

    {

        Students s =(Students)session.get(Students.class,1);

        System.out.println(s);

    }

    

    @Test

    public void testLoadStudents()

    {

        Students s =(Students)session.load(Students.class,1);

        System.out.println(s);

    }

    

    @Test

    public void testUpdateStudents()

    {

        Students s =(Students)session.load(Students.class,1);

        s.setGender("女");

        session.update(s);

    }

    

    @Test

    public void testDeleteStudents()

    {

        Students s =(Students)session.load(Students.class,1);

        session.delete(s);

    }

    

}

 

三 测试结果

1 get方法测试结果如下

Students [sid=1, sname=张三丰, gender=男, birthday=2017-10-02 09:36:35.0, address=Address@76fe8d1b]

 

2 load方法测试结果如下

Students [sid=1, sname=张三丰, gender=男, birthday=2017-10-02 09:36:35.0, address=Address@59e9c94]

 

3 update方法测试结果如下

 

 

4 delete方法测试结果如下

 

 

四 get与load的区别

 

 

1 测试1：是否立即发出SQL语句

1.1 测试代码：

        @Test

        public void testGetStudents()

        {

                Students s =(Students)session.get(Students.class,1);

                //System.out.println(s);

        }

        

        @Test

        public void testLoadStudents()

        {

                Students s =(Students)session.load(Students.class,1);

                //System.out.println(s);

        }

1.2 测试结果：

testGetStudents会在调试窗口输出下面语句

Hibernate:

    select

        students0_.SID as SID1_0_0_,

        students0_.SNAME as SNAME2_0_0_,

        students0_.GENDER as GENDER3_0_0_,

        students0_.BIRTHDAY as BIRTHDAY4_0_0_,

        students0_.PICTURE as PICTURE5_0_0_,

        students0_.POSTCODE as POSTCODE6_0_0_,

        students0_.PHOTO as PHOTO7_0_0_,

        students0_.ADDRESS as ADDRESS8_0_0_

    from

        STUDENTS students0_

    where

        students0_.SID=?

testLoadStudents不会在调试窗口输出结果

1.3 测试说明：

testLoadStudents只有在用的时候才发出SQL语句，是一种懒加载。

 

2 测试2：get返回对象本身，load返回代理对象

2.1 测试代码：

        @Test

        public void testGetStudents()

        {

                Students s =(Students)session.get(Students.class,1);

                System.out.println(s.getClass().getName());

                //System.out.println(s);

        }

        

        @Test

        public void testLoadStudents()

        {

                Students s =(Students)session.load(Students.class,1);

                System.out.println(s.getClass().getName());

                //System.out.println(s);

        }

2.2 测试结果：

get返回结果：

Students

load返回结果：

Students_$$_javassist_0

 

3 测试3：查询结果为空时区别

3.1 测试代码：

        @Test

        public void testGetStudents()

        {

                Students s =(Students)session.get(Students.class,100);

                //System.out.println(s.getClass().getName());

                System.out.println(s);

        }

        

        @Test

        public void testLoadStudents()

        {

                Students s =(Students)session.load(Students.class,100);

                //System.out.println(s.getClass().getName());

                System.out.println(s);

        }

3.2 测试结果：

get测试结果：

null

load测试结果：

 

抛出异常