mybatis(二)执行CRUD操作的两种方式配置和注解

时间：2022-09-30 08:05:52

一、使用MyBatis对表执行CRUD操作——基于XML的实现

1、定义sql映射xml文件

　　userMapper.xml文件的内容如下：

<?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.mi.mapping.UserInfoMapper">

     <select id="getUser" resultType="com.mi.entity.User">

        SELECT id,user_name userName,age FROM user_t where id=1

    </select>

     <!-- 创建用户(Create) -->

    <insert id="addUser" parameterType="com.mi.entity.User">

        insert into user_t(id,user_name,password,age) values(11,#{userName},0,#{age})

    </insert>

    <!-- 删除用户(Remove) -->

    <delete id="deleteUser" parameterType="int">

        delete from user_t where id=#{id}

    </delete>

    <!-- 修改用户(Update) -->

    <update id="updateUser" parameterType="com.mi.entity.User">

        update user_t set user_name=#{userName},age=#{age} where id=#{id}

    </update>

    <!-- 查询全部用户-->

    <select id="getAllUsers" resultType="com.mi.entity.User">

        select * from user_t

    </select>

</mapper>
package com.mi.demo;

import java.util.List;

import org.apache.ibatis.session.SqlSession;

import org.junit.Test;

import com.mi.entity.User;

public class TestCRUDByXmlMapper {

    @Test

    public void testAdd(){

        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);

        String statement = "com.mi.mapping.UserInfoMapper.addUser";

        User user = new User();

        user.setUserName("xinzhao");

        user.setAge(20);

        int insertResult = sqlSession.insert(statement,user);

        sqlSession.close();

        System.out.println(insertResult);

    }

    @Test

    public void testUpdate(){

        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);

        String statement = "com.mi.mapping.UserInfoMapper.updateUser";

        User user = new User();

        user.setId(11);

        user.setUserName("xinzhao");

        user.setAge(22);

        int result = sqlSession.update(statement, user);

        sqlSession.close();

        System.out.println(result);

    }

    @Test

    public void testDelete(){

        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);

        String statement = "com.mi.mapping.UserInfoMapper.deleteUser";

        User user = new User();

        user.setId(11);

        int result = sqlSession.delete(statement, user);

        sqlSession.close();

        System.out.println(result);

    }

    @Test

    public void testGetAll(){

        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);

        String statement = "com.mi.mapping.UserInfoMapper.getAllUsers";

        List<User> userList = sqlSession.selectList(statement);

        sqlSession.close();

        for(User user : userList){

            System.out.println(user.getUserName());

        }

    }

}

二、使用MyBatis对表执行CRUD操作——基于注解的实现

　　1、定义sql映射的接口

　　UserMapper接口的代码如下：

package com.mi.demo;

import java.util.List;

import org.apache.ibatis.annotations.Delete;

import org.apache.ibatis.annotations.Insert;

import org.apache.ibatis.annotations.Select;

import org.apache.ibatis.annotations.Update;

import com.mi.entity.User;

public interface UserMapper {

    @Insert(" insert into user_t(id,user_name,password,age) values(11,#{userName},0,#{age})")

    public int addUser(User user);

    @Delete("delete from user_t where id=#{id}")

    public int deleteById(int id);

    @Update("update user_t set user_name=#{userName},age=#{age} where id=#{id}")

    public int update(User user);

    @Select("SELECT id,user_name userName,age FROM user_t where id=1")

    public User getById(int id);

    @Select("select * from user_t")

    public List<User> getAll();

}

2、在conf.xml文件中注册这个映射接口

<?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" />

            <!-- 配置数据库连接信息 -->

            <dataSource type="POOLED">

                <property name="driver" value="com.mysql.jdbc.Driver" />

                <property name="url" value="jdbc:mysql://localhost/mi" />

                <property name="username" value="root" />

                <property name="password" value="dbdaocom" />

            </dataSource>

        </environment>

    </environments>

    <mappers>

        <mapper resource="com/mi/mapping/UserInfoMapper.xml"/><!-- 注册userMapper.xml文件， -->

        <mapper class="com.mi.demo.UserMapper"/><!-- 注册UserMapper映射接口-->

    </mappers>

</configuration>

单元测试类的代码如下：

package com.mi.demo;

import org.apache.ibatis.session.SqlSession;

import org.junit.Test;

import com.mi.entity.User;

public class TestCRUDByAnnotationMapper {

    @Test

    public void testAdd() {

        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);

        // 得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        User user = new User();

        user.setUserName("用户xdp");

        user.setAge(20);

        int result = mapper.addUser(user);

        sqlSession.close();

        System.out.println(result);

    }

    /**

     * ...the end

     */

}

用到的MyBatisUtil工具类代码如下：

package com.mi.demo;

import java.io.InputStream;

import org.apache.ibatis.session.SqlSession;

import org.apache.ibatis.session.SqlSessionFactory;

import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisUtil {

    /**

     * 获取SqlSessionFactory

     *

     * @return SqlSessionFactory

     */

    public static SqlSessionFactory getSqlSessionFactory() {

        // mybatis的配置文件

        String resource = "conf.xml";

        // 使用类加载器加载mybatis的配置文件（它也加载关联的映射文件）

        InputStream is = Test1.class.getClassLoader().getResourceAsStream(resource);

        // 构建sqlSession的工厂

        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(is);

        return sessionFactory;

    }

    /**

     * 获取SqlSession

     *

     * @return SqlSession

     */

    public static SqlSession getSqlSession() {

        return getSqlSessionFactory().openSession();

    }

    /**

     * 获取SqlSession

     *

     * @param isAutoCommit

     *            true 表示创建的SqlSession对象在执行完SQL之后会自动提交事务

     *            false表示创建的SqlSession对象在执行完SQL之后不会自动提交事务，这时就需要我们手动调用sqlSession.

     *            commit()提交事务

     * @return SqlSession

     */

    public static SqlSession getSqlSession(boolean isAutoCommit) {

        return getSqlSessionFactory().openSession(isAutoCommit);

    }

}

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