Mybatis基本使用

Posted 2023-05-22 逆梦

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1、创建maven项目，导入mybatis依赖。

<dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.4.SNAPSHOOT</version>
        </dependency>

2、创建MybatisConfig.xml配置连接文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org/DTD Config 3.0" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<!-- MyBatis的全局配置文件 -->
<configuration >
    <!-- 1.配置环境，可配置多个环境（比如：develop开发、test测试） -->
    <environments default="develop">
        <environment id="develop">
            <!-- 1.1.配置事务管理方式：JDBC/MANAGED
            JDBC：将事务交给JDBC管理（推荐）
            MANAGED：自己管理事务
              -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- 1.2.配置数据源，即连接池 JNDI/POOLED/UNPOOLED
                JNDI：已过时
                POOLED：使用连接池（推荐）
                UNPOOLED：不使用连接池
             -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/user-mode?characterEncoding=utf-8"/>
                <property name="username" value="root"/>
                <property name="password" value="1234qwer"/>
            </dataSource>
        </environment>
    </environments>
    <!-- 2.导入Mapper配置文件，如果mapper文件有多个，可以通过多个mapper标签导入-->
    <mappers>
        <mapper resource="mapper/UserMapper.xml"/>
    </mappers>
</configuration>

3、创建User用户实体类

@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class User 
    private Long id;

    /**
     * 名称
     */
    private String name;

    /**
     * 邮箱
     */
    private String email;

    /**
     * 手机号
     */
    private String phoneNumber;

4、创建用户model接口

@Mapper
public interface UserMapper 

    List<User> getPageUser(@Param("name") String name);

    void insertUser(User user);

    void updateUser(User user);

    void deletetUser(Long userId);

5、创建映射文件UserMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org/DTD Mapper 3.0" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itmy.dao.UserMapper">

    <resultMap id="userRmap" type="com.itmy.model.entity.User">
        <result jdbcType="VARCHAR" javaType="java.lang.String" column="name" />
    </resultMap>

    <select id="getPageUser" resultType="com.itmy.model.entity.User" parameterType="string">
        select * from tb_user
        <where>
            <if test="name != null and \'\' != name">
                name like CONCAT(\'%\',#name,\'%\');
            </if>
        </where>
    </select>

    <insert id="insertUser" parameterType="com.itmy.model.entity.User">
        INSERT INTO `tb_user`
        (`name`, `account`,`password`, `email`,phone_number,remark)
        VALUES
        (#name, #account, #password, #email,#phoneNumber,#remark);
    </insert>

    <update id="updateUser" parameterType="com.itmy.model.entity.User">
        UPDATE tb_user
        <set>
            <if test="name != null and \'\' != name">
                name = #name,
            </if>
            <if test="account != null and \'\' != account">
                account = #account,
            </if>
            <if test="password != null and \'\' != password">
                password = #password,
            </if>
            <if test="email != null and \'\' != email">
                email = #email,
            </if>
            <if test="phoneNumber != null and \'\' != phoneNumber">
                phone_number = #phoneNumber,
            </if>
            <if test="remark != null and \'\' != remark">
                remark = #remark,
            </if>
        </set>
        where id = #id
    </update>

    <delete id="deletetUser" parameterType="java.lang.Long">
        DELETE FROM tb_user WHERE id = #userId
    </delete>
</mapper>

6、在测试类中编写测试文件MTest.java

public class Test 

    InputStream inputStream;

    SqlSession sqlSession;
    @Before
    public void beforeSql() throws IOException 
        inputStream = Resources.getResourceAsStream("MybatisConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        sqlSession = sqlSessionFactory.openSession();
    

    @org.junit.Test
    public void querySql()
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        List<User> pageUser = userMapper.getPageUser(null);
        for (int i = 0; i < pageUser.size(); i++) 
            System.out.println(pageUser.get(i));
        
    

    @org.junit.Test
    public void insertSql()
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user=new User();
        user.setAccount("aaaaa@qq.com");
        user.setEmail("aaaaa@qq.com");
        user.setName("掌声");
        user.setPassword("SDWAR!@");
        user.setPhoneNumber("12345");
        user.setRemark("测试优化信息");
        userMapper.insertUser(user);
        sqlSession.commit();
        System.out.println();
    

    @org.junit.Test
    public void updateSql()
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user=new User();
        user.setAccount("bbabbb@qq.com");
        user.setEmail("bbbabb@qq.com");
        user.setName("掌声bb");
        user.setPassword("SDbbWAR!@");
        user.setPhoneNumber("12345");
        user.setRemark("测试优化b信息");
        user.setId(5L);
        userMapper.updateUser(user);
        System.out.println();
        sqlSession.commit();
    

    @org.junit.Test
    public void deleteSql()
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        userMapper.deletetUser(6L);
        System.out.println();
        sqlSession.commit();
    


    @After
    public void afterSql() throws IOException 
        sqlSession.close();
        inputStream.close();

mybatis基本使用

一、介绍

持久层框架

官方文档：http://www.mybatis.org/mybatis-3/zh/index.html

二、基本使用

1.创建项目和模块

2.添加pom.xml

<dependencies>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.2.1</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.17</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.11</version>
    </dependency>
</dependencies>

3.添加配置

resoucecs/mybatis-config.xml

<?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://192.168.137.101:3306/mybatis"/>
                <property name="username" value="root"/>
                <property name="password" value="mysql"/>
            </dataSource>
        </environment>
    </environments>
</configuration>

4.创建库和表

mysql>create database mybatis ;
mysql>use mybatis ;
mysql>create table users(id int primary key auto_increment , name varchar(20) ,age int) ;
mysql>desc users ;

5.测试连接

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;

public class App {
    public static void main(String[] args) {
        try {
            //指定配置文件的路径(类路径)
            String resource = "mybatis-config.xml";
            //加载文件
            InputStream inputStream = Resources.getResourceAsStream(resource);

            //创建会话工厂Builder,相当于连接池
            SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);

            //通过sf开启会话，相当于打开连接。
            SqlSession s = sf.openSession();
            System.out.println(s);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

6.编写mapper文件

6.1)创建User类，和users对应

public class User {
    private Integer id ;
    private String name ;
    private int age ;
    //get/set
}

6.2)创建UserMapper.xml,存放在resources/目录下

resources/UserMapper.xml

<?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">
<!-- 定义名字空间 -->
<mapper namespace="users">
    <!-- 定义insert语句 -->
    <insert id="insert">
      insert into users(name,age) values(#{name},#{age})
    </insert>
</mapper>

7.在resources/mybatis-config.xml文件中引入mapper的xml文件.

<?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://192.168.137.101:3306/mybatis"/>
                <property name="username" value="root"/>
                <property name="password" value="mysql"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="UserMapper.xml"/>
    </mappers>
</configuration>

8.编写单元测试，实现插入.

@Test
public void insert() throws Exception {
    //指定配置文件的路径(类路径)
    String resource = "mybatis-config.xml";
    //加载文件
    InputStream inputStream = Resources.getResourceAsStream(resource);

    //创建会话工厂Builder,相当于连接池
    SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);

    //通过sf开启会话，相当于打开连接。
    SqlSession s = sf.openSession();
    User u = new User();

    u.setName("jerry");
    u.setAge(2);
    s.insert("users.insert", u);
    s.commit();
    s.close();
}

9.完成update-selectOne-selectAll操作。

9.1)编写UserMapper.xml，添加相应的元素

<?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="users">
    <insert id="insert">
      insert into users(name,age) values(#{name},#{age})
    </insert>
    <update id="update">
        update users set name = #{name} , age = #{age} where id = #{id}
    </update>

    <!-- selectOne -->
    <select id="selectOne" parameterType="int" resultType="com.niu.mybatisdemo.domain.User">
        select * from users where id = #{id}
    </select>

    <!-- selectAll -->
    <select id="selectAll" resultType="com.niu.mybatisdemo.domain.User">
        select * from users
    </select>
</mapper>

9.2)编写测试程序

@Test
public void insert() throws Exception {
    //指定配置文件的路径(类路径)
    String resource = "mybatis-config.xml";
    //加载文件
    InputStream inputStream = Resources.getResourceAsStream(resource);

    //创建会话工厂Builder,相当于连接池
    SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);

    //通过sf开启会话，相当于打开连接。
    SqlSession s = sf.openSession();
    User u = new User();

    u.setName("jerry");
    u.setAge(2);
    s.insert("users.insert", u);
    s.commit();
    s.close();
}

@Test
public void update() throws Exception {
    String resource = "mybatis-config.xml";
    InputStream inputStream = Resources.getResourceAsStream(resource);
    SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);
    SqlSession s = sf.openSession();
    User u = new User();
    u.setId(1);
    u.setName("tomas");
    u.setAge(32);
    s.update("users.update", u);
    s.commit();
    s.close();
}

@Test
public void selectOne() throws Exception {
    String resource = "mybatis-config.xml";
    InputStream inputStream = Resources.getResourceAsStream(resource);
    SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);
    SqlSession s = sf.openSession();
    User user = s.selectOne("users.selectOne",1);
    System.out.println(user.getName());
    s.commit();
    s.close();
}

@Test
public void selectAll() throws Exception {
    String resource = "mybatis-config.xml";
    InputStream inputStream = Resources.getResourceAsStream(resource);
    SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);
    SqlSession s = sf.openSession();
    List<User> users = s.selectList("users.selectAll");
    for(User uu : users){
        System.out.println(uu.getName() + "," + uu.getAge());
    }
    s.commit();
    s.close();
}

三、复杂应用

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