准备工作：1.创建一个maven工程，然后将pojo类导入到项目中去。

                   2.导入依赖到pom.xml文件中

                   3.在resources中创建log4j.properites和mybatis-config.xml

                   4.创建UserMapper接口和UserMapper.xml文件

                   5.创建测试类MyBatisTest

1.创建Maven工程，还没有配置Maven的和还不会的去看这里啦：maven的下载安装与配置环境变量！！！（全网最详细）-CSDN博客

2.导入依赖到pom.xml文件中

<dependencies>
        <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.4.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>
    <build>
        <!-- 如果不添加此节点src/main/java目录下的所有配置文件都会被漏掉。 -->
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
        </resources>
    </build>

     3.在resources中创建log4j.properites和mybatis-config.xml

log4j.properites:

# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

 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>
    <!--使用dev环境-->
    <environments default="dev">
        <!--dev环境-->
        <environment id="dev">
            <transactionManager type="JDBC"></transactionManager>
            <!--使用连接池中的数据源-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3305/mybatis?characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value=""/>
            </dataSource>
        </environment>
    </environments>
    <!-- 扫描映射文件 -->
    <mappers>
        <mapper resource="com/by/mapper/UserMapper.xml"/>
    </mappers>
</configuration>

 

4.创建UserMapper接口和UserMapper.xml文件

UserMapper.java:

package com.by.mapper;

import com.by.pojo.User;
import org.apache.ibatis.annotations.Param;

import java.util.Map;

/**
 * <p>Project: mybatis - UserMapper</p>
 * <p>Powered by scl On 2023-12-19 15:24:18</p>
 * <p>描述：<p>
 *
 * @author 孙臣龙 [1846080280@qq.com]
 * @version 1.0
 * @since 17
 */
public interface UserMapper {
    User getUserById(Integer id );

    User getUser(Integer id , String username);

    User getUser1(@Param("id") Integer id , @Param("username") String username);

    User getUser2(User user);
    User getUser3(Map<String ,Object> map);
}

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">
<mapper namespace="com.by.mapper.UserMapper">

    <select id="getUserById" resultType="com.by.pojo.User">
        select * from user where id=#{id}
    </select>
    <select id="getUser" resultType="com.by.pojo.User">
        <!--select * from user where id=#{arg0} and username=#{arg1};-->
        select * from user where id=#{param1} and username=#{param2};

    </select>
    <select id="getUser1" resultType="com.by.pojo.User">
        select * from user where id=#{id} and username=#{username}
    </select>
    <select id="getUser2" parameterType="com.by.pojo.User" resultType="com.by.pojo.User">
        select * from user where id=#{id} and username=#{username}
    </select>
    <select id="getUser3" parameterType="java.util.Map" resultType="com.by.pojo.User">
        select * from user where id=#{id} and username=#{username}
    </select>
</mapper>

5.创建测试类MyBatisTest

/*
 * Copyright (c) 2020, 2023,  All rights reserved.
 *
 */
package com.by;

import com.by.mapper.UserMapper;
import com.by.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.After;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;


/**
 * <p>Project: mybatis - MyBatisTest</p>
 * <p>Powered by scl On 2023-12-18 11:44:53</p>
 * <p>描述：<p>
 *
 * @author 孙臣龙 [1846080280@qq.com]
 * @version 1.0
 * @since 17
 */
public class MyBatisTest {

    private InputStream inputStream;
    private SqlSession sqlSession;


    @Before
    public void init() throws IOException {
        // 加载配置文件
        String resource = "mybatis-config.xml";
        inputStream = Resources.getResourceAsStream(resource);

        // 创建sqlSessionFActory
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 获得数据的绘画实例
        sqlSession = sessionFactory.openSession();
    }

    /**
     * 传递单个参数
     * @throws IOException
     */
    @Test
    public void testGetById() throws IOException {
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.getUserById(43);
        System.out.println(user);
    }
    /**
     * 传递多个参数
     * @throws IOException
     */
    @Test
    public void testGetUser() throws IOException {
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.getUser(43,"俞莲舟");
        System.out.println(user);
    }
    /**
     * 注解传递多个参数
     * @throws IOException
     */
    @Test
    public void testGetUser1() throws IOException {
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.getUser(43,"俞莲舟");
        System.out.println(user);
    }
    /**
     * 对象传递多个参数
     * @throws IOException
     */
    @Test
    public void testGetUser2() throws IOException {
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user1 = new User();
        user1.setId(43);
        user1.setUsername("俞莲舟");
        User user = userMapper.getUser2(user1);
        System.out.println(user);
    }
    /**
     * map传递多个参数
     * @throws IOException
     */
    @Test
    public void testGetUser3() throws IOException {
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        Map<String ,Object> m = new HashMap<>();
        m.put("id",43);
        m.put("username","俞莲舟");
        User user = userMapper.getUser3(m);
        System.out.println(user);
    }

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

}