<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>5.1.6</version>
        </dependency>
        <!--这个是日志文件，用来优化mybatis的-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
      <!-- junit是用来测试dao层的-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>

<?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>
    <settings>
        <!--开启延迟加载-->
        <setting name="lazyLoadingEnabled" value="true" />
        <!--是否开启积极懒加载，false 按需加载 ，默认是true-->

        <setting name="aggressiveLazyLoading" value="false" />

        <!--开启二级缓存 总开关-->
        <setting name="cacheEnabled" value="true" />
    </settings>

    <typeAliases>
        <!-- <typeAlias type="net.seehope.mybatis.pojo.User" alias="user" /> -->
        <!--批量别名 首字母大小写都行-->
        <package name="net.seehope.mybatis.pojo" />
    </typeAliases>
    
    <environments default="development">
        <environment id="development">
            <!--配置JDBC事务控制，由mybatis 管理-->
            <transactionManager type="JDBC"/>
            <!--默认使用dbcp连接池-->
            <!--这儿value要使用自己的数据库,我这里是使用了配置文件-->
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}" />
                <property name="url" value="${jdbc.url}" />
                <property name="username" value="${jdbc.username}" />
                <property name="password" value="${jdbc.password}" />
            </dataSource>
        </environment>
        <!-- <environment id="development1">
            配置JDBC事务控制，由mybatis 管理
            <transactionManager type="JDBC"></transactionManager>
            默认使用dbcp连接池
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/spring_jdbc" />
                <property name="username" value="root" />
                <property name="password" value="qhxj,YRAN941211" />
            </dataSource>
        </environment>
 -->
    </environments>
</configuration>

public interface UserMapper {
//这个接口中有一个添加用户的方法，也可以写多个。
    int addUser();
}

<?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">
<!-- namespace：此时用mapper代理方式，它的值必须等于对应mapper接口的全限定名  -->
<!--namespace的名字就是java目录后一级，mapper里面写相应的sql语句-->
<mapper namespace="com.example.ktp.mapper.UserMapper">
     <!--语句的id指向接口中的方法名-->
     <insert id="addUser">
         insert into ktp_user(name,password) values ("ss","ssssss");
     </insert>
     <!--select语句必须要有返回类型，resultType 或 resultMap-->
     <select id="selectByIdUser" resultType="UserMapper">
        
    </select>
</mapper>

import com.example.ktp.mapper.UserMapper;
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;

public class test_user_mapper {
  @Test
 public void testUser() throws IOException {
       InputStream is= Resources.getResourceAsStream("mybatis_config.xml");
       //通过SqlSessionFactoryBuilder去构建SqlSessionFactory
      SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder();
      //再通过SqlSessionFactory和配置文件去构建SqlSession
      SqlSessionFactory sqlSessionFactory=builder.build(is);
       //Sqlsession文件充当java程序和数据库的桥梁
      SqlSession sqlSession=sqlSessionFactory.openSession(true);
      //Sqlsession文件通过接口的class文件去创建类
      UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
      //使用这个方法，返回为1，则成功了
      int t=userMapper.addUser();
      System.out.println("Result: "+t);
  }
}