实例介绍MyBatis增删改查基本操作

刺骨的言语ヽ痛彻心扉 2022-05-27 01:22 213阅读 0赞

通过上一篇博客《MyBatis的入门介绍》我们了解了MyBatis基本原理  
这篇我们就说说它的增删改查基本操作

--------------------

## 实例应用 ##

创建Java Product项目，目录结构如下：

![这里写图片描述][70]

## 数据库结构如下 ##

![这里写图片描述][70 1]

### conf.xml文件内容 ###

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-config.dtd">
    <configuration>
        <environments default="development">
            <environment id="development">
                <transactionManager type="JDBC" />
                <dataSource type="POOLED">
                    <property name="driver" value="com.mysql.jdbc.Driver" />
                    <property name="url" value="jdbc:mysql://localhost:3306/mybatis" />
                    <property name="username" value="root" />
                    <property name="password" value="123456" />
                </dataSource>
            </environment>
        </environments>
        <mappers>
            <mapper resource="com/atguigu/day03_mybaits/test2/userMapper.xml"/>
        </mappers>
    </configuration>

### userMapper.xml文件内容 ###

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="com.atguigu.day03_mybaits.test2.userMapper">
    
        <insert id="addUser" parameterType="com.atguigu.day03_mybaits.test2.User">
            INSERT INTO users(name,age) VALUE (#{name},#{age})
        </insert>
    
        <delete id="deleteUser" parameterType="int">
              DELETE FROM users WHERE id=#{id}
        </delete>
    
        <update id="updateUser" parameterType="com.atguigu.day03_mybaits.test2.User">
            UPDATE users set NAME=#{name},age=#{age} where id=#{id}
        </update>
    
        <select id="getUser" parameterType="int"
                resultType="com.atguigu.day03_mybaits.test2.User">
            select * from users where id=#{id}
        </select>
    
        <select id="getAllUsers" resultType="com.atguigu.day03_mybaits.test2.User">
            SELECT * FROM users
        </select>
    </mapper>

### Test2类添加方法 ###

public void testAdd(){
        //找配置文件和数据库连接
            String resource = "conf.xml";
            InputStream is=Test.class.getClassLoader().getResourceAsStream(resource);
    	//创建SqlSessionFactory对象
            SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(is);
            //openSession默认手动提交，里面参数为true默认自动提交
            SqlSession session=factory.openSession();
    	//指定MyBatis执行的xml文件
            String statement="com.atguigu.day03_mybaits.test2.userMapper.addUser";
            User u=new User();
            u.setId(-1);
            u.setName("KK");
            u.setAge(23);
            int insert=session.insert(statement,u);
            //手动提交方式
            session.commit();
            System.out.println(insert);
        }

### Test2类更新方法 ###

public void testUpdate(){
        //找配置文件和数据库连接
            String resource = "conf.xml";
            InputStream is=Test.class.getClassLoader().getResourceAsStream(resource);
    	//创建SqlSessionFactory对象
            SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(is);
            //openSession默认手动提交，里面参数为true默认自动提交
            SqlSession session=factory.openSession();
    	//指定MyBatis执行的xml文件
            String statement="com.atguigu.day03_mybaits.test2.userMapper.addUser";
            User u=new User();
            u.setId(5);
            u.setName("KK");
            u.setAge(25);
            int insert=session.update(statement,u);
            //手动提交方式
            session.commit();
            System.out.println(insert);
        }

### Test2类删除方法 ###

public void testDelete(){
        //找配置文件和数据库连接
            String resource = "conf.xml";
            InputStream is=Test.class.getClassLoader().getResourceAsStream(resource);
    	//创建SqlSessionFactory对象
            SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(is);
            //openSession默认手动提交，里面参数为true默认自动提交
            SqlSession session=factory.openSession();
    	//指定MyBatis执行的xml文件
            String statement="com.atguigu.day03_mybaits.test2.userMapper.addUser";
    		int insert=session.delete(statement,5);
            //手动提交方式
            session.commit();
            System.out.println(insert);
        }

### Test2类查找一条方法 ###

public void testGetUser(){
        //找配置文件和数据库连接
            String resource = "conf.xml";
            InputStream is=Test.class.getClassLoader().getResourceAsStream(resource);
    	//创建SqlSessionFactory对象
            SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(is);
            //openSession默认手动提交，里面参数为true默认自动提交
            SqlSession session=factory.openSession();
    	//指定MyBatis执行的xml文件
            String statement="com.atguigu.day03_mybaits.test2.userMapper.addUser";
    		User u=session.selectOne(statement,1);
            //手动提交方式
            session.commit();
            System.out.println(u);
        }

### Test2类查找全部方法 ###

public void testGetAll(){
        //找配置文件和数据库连接
            String resource = "conf.xml";
            InputStream is=Test.class.getClassLoader().getResourceAsStream(resource);
    	//创建SqlSessionFactory对象
            SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(is);
            //openSession默认手动提交，里面参数为true默认自动提交
            SqlSession session=factory.openSession();
    	//指定MyBatis执行的xml文件
            String statement="com.atguigu.day03_mybaits.test2.userMapper.addUser";
    		List<User>list=session.selectList(statement);
            //手动提交方式
            session.commit();
            System.out.println(list);
        }

[70]: /images/20220527/7b5975ff106347aa8ebfedec6c09cac6.png
[70 1]: /images/20220527/8108b86ae3934594af7025abcfbdb565.png