CYY's Blog
Mybatis使用入门
CYY
  2021-09-29 22:56:41   2021-09-29 22:56:41  

快速入门

1.
导入maven坐标（jar包）

-
msql驱动

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<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.25</version>
</dependency>

-
mybatis

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<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.5.7</version>
</dependency>

2.
创建表以及实体类

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USE test;

CREATE TABLE `user`(
`id` INT PRIMARY KEY AUTO_INCREMENT,
`username` VARCHAR(15),
`password` VARCHAR(15)
)

INSERT INTO `user`(`username`,`p`USER`assword`) VALUES('cyy','123456');
INSERT INTO `user` (`username`,`password`) VALUES('hi','123456');
INSERT INTO `user` (`username`,`password`) VALUES('jjb','123456');
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public class User {
    private Integer id;
    private String username;
    private String password;
    public User() {
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

3.
编写映射文件xxxmapper.xml

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<?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="userMapper">
    <select id="findAll" resultType="com.study.pojo.User">
        select * from user
    </select>

    <insert id="sava" parameterType="com.study.pojo.User">
        insert into user values(#{id},#{username},#{password})
    </insert>

    <delete id="deleteUser" parameterType="java.lang.Integer">
        delete from user where id = #{id}
    </delete>

    <update id="updateUser" parameterType="com.study.pojo.User">
        update user set username=#{username},password=#{password} where id=#{id}
    </update>
</mapper>

4.
编写mybatis核心配置

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<?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>
    <!--配置数据源环境-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql:///test"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    <!--加载映射文件-->
    <mappers>
        <mapper resource="com/study/mapper/userMapper.xml"></mapper>
    </mappers>
</configuration>

5.
进行测试

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package com.study.test;

import com.study.pojo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 * @Auther: cyy
 * @Date: 2021/9/17 22 57
 * @Description:测试mybatis的增加删改，未进行抽取
 */
public class MybatisTest {
    //查
    @Test
    public void test1() throws IOException {
        //加载核心配置文件
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        //获得sqlSession工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        //获得sqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //执行操作
        List<User> users = sqlSession.selectList("userMapper.findAll");
        System.out.println(users);
        sqlSession.close();
    }

    @Test
    public void test2() throws IOException {
        //删
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = factory.openSession();
        sqlSession.delete("userMapper.deleteUser",new Integer(8));
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void test3() throws IOException {
        //增
        User user = new User();
        user.setUsername("gg4");
        user.setPassword("123456");
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = factory.openSession();
        sqlSession.insert("userMapper.sava",user);
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void test4() throws IOException {
        //改
        User user = new User();
        user.setId(10);
        user.setUsername("bb4");
        user.setPassword("654321");
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = factory.openSession();
        sqlSession.update("userMapper.updateUser",user);
        sqlSession.commit();
        sqlSession.close();
    }
}

mybatis传统实现

1.
数据库和pojo同上

2.
dao层

-
接口

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package com.study.mapper;

import com.study.pojo.User;

import java.io.IOException;
import java.util.List;

/**
 * @Auther: cyy
 * @Date: 2021/9/22 22 53
 * @Description:
 */
public interface UserMapper {
    public List<User> findAll() throws IOException;
    public User findOneById(Integer id) throws IOException;
    public void saveUser(User user) throws IOException;
    public void deleteUser(Integer id) throws IOException;
    public void updateUser(User newUser) throws IOException;
}

-
对应实现

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package com.study.mapper.impl;

import com.study.mapper.UserMapper;
import com.study.pojo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 * @Auther: cyy
 * @Date: 2021/9/22 23 01
 * @Description:
 */
public class UserMapperImpl implements UserMapper {
    @Override
    public List<User> findAll() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        return sqlSession.selectList("userMapper.findAll");
    }

    @Override
    public User findOneById(Integer id) throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        return sqlSession.selectOne("userMapper.findOneById",id);
    }

    @Override
    public void saveUser(User user) throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        sqlSession.insert("userMapper.saveUser",user);
        sqlSession.commit();
    }

    @Override
    public void deleteUser(Integer id) throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        sqlSession.delete("userMapper.deleteUser",id);
        sqlSession.commit();
    }

    @Override
    public void updateUser(User newUser) throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        sqlSession.update("userMapper.updateUser",newUser);
        sqlSession.commit();
    }
}

3.
mybatis映射文件

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<?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="userMapper">
    <select id="findAll" resultType="com.study.pojo.User">
        select * from user
    </select>

    <select id="findOneById" parameterType="int" resultType="com.study.pojo.User">
        select * from user where id=#{id};
    </select>
    <insert id="saveUser" parameterType="com.study.pojo.User">
        insert into user values(#{id},#{username},#{password})
    </insert>

    <delete id="deleteUser" parameterType="int">
        delete from user where id = #{ids}
    </delete>

    <update id="updateUser" parameterType="com.study.pojo.User">
        update user set username=#{username},password=#{password} where id=#{id}
    </update>
</mapper>

4.
测试dao层

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package com.study.mapper.impl;

import com.study.mapper.UserMapper;
import com.study.pojo.User;
import org.junit.jupiter.api.Test;

import java.io.IOException;

import static org.junit.jupiter.api.Assertions.*;

class UserMapperImplTest {

    UserMapper userMapper = new UserMapperImpl();
    @Test
    void findAll() throws IOException {
        System.out.println(userMapper.findAll());
    }

    @Test
    void findOneById() throws IOException {
        System.out.println(userMapper.findOneById(1));
    }

    @Test
    void saveUser() throws IOException {
        User user = new User();
        user.setUsername("gg23232");
        user.setPassword("hha333hd");
        userMapper.saveUser(user);
    }

    @Test
    void deleteUser() throws IOException {
        userMapper.deleteUser(10);
    }

    @Test
    void updateUser() throws IOException {
        User user = new User();
        user.setId(9);
        user.setUsername("ggg");
        user.setPassword("hhasdha");
        userMapper.updateUser(user);
    }
}

mybatis接口代理方式实现

注意：映射xml文件里的namespace属性值要是接口的全类名，

映射xml文件里的sql语句id属性值要与接口方法对应

1.
数据库和pojo同上

2.
dao层接口

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package com.study.mapper;

import com.study.pojo.User;

import java.io.IOException;
import java.util.List;

/**
 * @Auther: cyy
 * @Date: 2021/9/22 22 53
 * @Description:
 */
public interface UserMapper {
    public List<User> findAll() throws IOException;
    public User findOneById(Integer id) throws IOException;
    public void saveUser(User user) throws IOException;
    public void deleteUser(Integer id) throws IOException;
    public void updateUser(User newUser) throws IOException;
}

3.
mybatis映射文件

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<?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.study.mapper.UserMapper">
    <select id="findAll" resultType="com.study.pojo.User">
        select * from user
    </select>

    <select id="findOneById" parameterType="int" resultType="com.study.pojo.User">
        select * from user where id=#{id};
    </select>
    <insert id="saveUser" parameterType="com.study.pojo.User">
        insert into user values(#{id},#{username},#{password})
    </insert>

    <delete id="deleteUser" parameterType="int">
        delete from user where id = #{ids}
    </delete>

    <update id="updateUser" parameterType="com.study.pojo.User">
        update user set username=#{username},password=#{password} where id=#{id}
    </update>
</mapper>

4.
测试

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package com.study.mapper;

import com.study.pojo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.jupiter.api.Test;
import org.springframework.core.io.Resource;
import org.w3c.dom.ls.LSOutput;

import java.io.IOException;
import java.io.InputStream;

import static org.junit.jupiter.api.Assertions.*;

class UserMapperTest {

    @Test
    void findAll() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        System.out.println(mapper.findAll());

    }

    @Test
    void findOneById() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        System.out.println(mapper.findOneById(1));
    }

    @Test
    void saveUser() throws IOException {
        User user = new User();
        user.setUsername("gg22");
        user.setPassword("hha");

        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.saveUser(user);
        sqlSession.commit();
    }

    @Test
    void deleteUser() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.deleteUser(12);
        sqlSession.commit();
    }

    @Test
    void updateUser() throws IOException {
        User user = new User();
        user.setId(9);
        user.setUsername("gg22");
        user.setPassword("hha");

        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = build.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.updateUser(user);
        sqlSession.commit();
    }
}
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  1. 快速入门
  2. mybatis传统实现
  3. mybatis接口代理方式实现
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  1. 快速入门
  2. mybatis传统实现
  3. mybatis接口代理方式实现