加入log4j日志功能

加入依赖

<!-- log4j日志 -->

<dependency>

<groupId>log4j</groupId>

<artifactId>log4j</artifactId>

<version>1.2.17</version>

</dependency>

加入log4j的配置文件

log4j的配置文件名为log4j.xml，存放的位置是src/main/resources目录下
日志的级别：FATAL(致命)>ERROR(错误)>WARN(警告)>INFO(信息)>DEBUG(调试) 从左到右打印的内容越来越详细

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">

    <appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">

        <param name="Encoding" value="UTF-8" />

        <layout class="org.apache.log4j.PatternLayout">

			<param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) \n" />

        </layout>

    </appender>

    <logger name="java.sql">

        <level value="debug" />

    </logger>

    <logger name="org.apache.ibatis">

        <level value="info" />

    </logger>

    <root>

        <level value="debug" />

        <appender-ref ref="STDOUT" />

    </root>

</log4j:configuration>

MyBatis的增删改查

添加

<!--int insertUser();-->

<insert id="insertUser">

	insert into t_user values(null,'admin','123456',23,'男','12345@qq.com')

</insert>

删除

<!--int deleteUser();-->

<delete id="deleteUser">

    delete from t_user where id = 6

</delete>

修改

<!--int updateUser();-->

<update id="updateUser">

    update t_user set username = '张三' where id = 5

</update>

查询一个实体类对象

<!--User getUserById();-->

<select id="getUserById" resultType="com.atguigu.mybatis.bean.User">

	select * from t_user where id = 2

</select>

查询集合

<!--List<User> getUserList();-->

<select id="getUserList" resultType="com.atguigu.mybatis.bean.User">

	select * from t_user

</select>

注意：
1. 查询的标签select必须设置属性resultType或resultMap，用于设置实体类和数据库表的映射关系
  - resultType：自动映射，用于属性名和表中字段名一致的情况
  - resultMap：自定义映射，用于一对多或多对一或字段名和属性名不一致的情况
2. 当查询的数据为多条时，不能使用实体类作为返回值，只能使用集合，否则会抛出异常TooManyResultsException；但是若查询的数据只有一条，可以使用实体类或集合作为返回值

测试类

juit测试类



import com.atguigu.mybatis.mapper.userMapper;

import com.atguigu.mybatis.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;

public class MyBatisTest {

    /**

     * 往t_user表中插入数据

     * @return 1

     * @throws IOException

     */

    @Test

public void testInsertUser() throws IOException {

    //读取MyBatis的核心配置文件

    InputStream is = Resources.getResourceAsStream("mybatis-config.xml");

    //获取SqlSessionFactoryBuilder对象

    SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();

    //通过核心配置文件所对应的字节输入流创建工厂类SqlSessionFactory，生产SqlSession对象

    SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);

    //获取sqlSession，此时通过SqlSession对象所操作的sql都必须手动提交或回滚事务

    //SqlSession sqlSession = sqlSessionFactory.openSession();

    //创建SqlSession对象，此时通过SqlSession对象所操作的sql都会自动提交

    SqlSession sqlSession = sqlSessionFactory.openSession(true);

    //通过代理模式创建UserMapper接口的代理实现类对象

    userMapper userMapper = sqlSession.getMapper(userMapper.class);

    //调用UserMapper接口中的方法，就可以根据UserMapper的全类名匹配元素文件，通过调用的方法名匹配映射文件中的SQL标签，并执行标签中的SQL语句

    int result = userMapper.insertUser();

    //提交事务

    //sqlSession.commit();

    System.out.println("result:" + result);

}

    /**

     * 往t_user表中更新数据

     * @throws IOException

     */

    @Test

    public void testUpdateUser() throws IOException {

        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");

        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();

        SqlSessionFactory build = sqlSessionFactoryBuilder.build(resourceAsStream);

        SqlSession sqlSession = build.openSession(true);

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

        mapper.updateUser();

        System.out.println("1111");

    }

    /**

     * 删除t_user表中的数据

     * @throws IOException

     */

    @Test

    public void testDeleteUser() throws IOException {

        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");

        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();

        SqlSessionFactory build = sqlSessionFactoryBuilder.build(resourceAsStream);

        SqlSession sqlSession = build.openSession(true);

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

        mapper.deleteUser();

    }

    /**

     * 通过id来查询t_user表格

     * @throws IOException

     */

    @Test

    public void  testGetUserById() throws IOException {

        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");

        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();

        SqlSessionFactory build = sqlSessionFactoryBuilder.build(resourceAsStream);

        SqlSession sqlSession = build.openSession(true);

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

        user userById = mapper.getUserById();

        System.out.println(userById.toString());

    }

    /**

     * 查询t_user表中所有的数据

     * @throws IOException

     */

    @Test

    public void TestGetAllUser() throws IOException {

        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");

        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();

        SqlSessionFactory build = sqlSessionFactoryBuilder.build(resourceAsStream);

        SqlSession sqlSession = build.openSession(true);

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

        List<user> allUser = mapper.getAllUser();

        allUser.forEach(user -> System.out.println(user.toString()));

    }

}

巴特西

mybatis-增删改查和配置

加入log4j日志功能

MyBatis的增删改查

测试类

juit测试类

结果

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