Mybatis 日志(Log4j2)

之前我们介绍了使用JDK Log、Apache Commons Logging打印Mybatis运行时的日志；本篇我们介绍使用Log4j2打印Mybatis运行时的日志。

如何您对Mybatis中使用JDK Log、Apache Commons Logging打印Mybatis运行时的日志不太了解，可以参考：

Mybatis 日志(JDK Log)https://blog.csdn.net/m1729339749/article/details/132565362Mybatis 日志(Apache Commons Logging)https://blog.csdn.net/m1729339749/article/details/133266537

一、添加依赖

<dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.4.5</version>
</dependency>
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.49</version>
</dependency>
<dependency><groupId>org.apache.logging.log4j</groupId><artifactId>log4j-api</artifactId><version>2.20.0</version>
</dependency>
<dependency><groupId>org.apache.logging.log4j</groupId><artifactId>log4j-core</artifactId><version>2.20.0</version>
</dependency>

二、配置Mybatis

在mybatis-config.xml文件中配置logImpl

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><settings><setting name="logImpl" value="LOG4J2"/></settings><environments default="development"><environment id="development"><transactionManager type="JDBC"/><dataSource type="POOLED"><property name="driver" value="org.gjt.mm.mysql.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/demo?useUnicode=true&amp;useSSL=false&amp;characterEncoding=utf8"/><property name="username" value="root"/><property name="password" value="horse"/></dataSource></environment></environments>
</configuration>

在配置文件中，我们配置了logImpl，值配置成了LOG4J2，代表的是使用Log4j2提供的日志系统

三、Log4j2日志配置

1、log4j2.component.properties

在resources目录下新建log4j2.component.properties配置文件

log4j.configurationFile=log4j2.properties

log4j.configurationFile用于指定log4j2的配置文件

2、log4j2.properties

在resources目录下新建log4j2.properties配置文件

status = ERRORlogger.action.name = cn.horse.demo.UserInfoMapper
logger.action.level = debug

log4j2.properties配置文件中配置了日志的级别

四、启动程序

1、准备数据

-- 如果数据库不存在则创建数据库
CREATE DATABASE IF NOT EXISTS demo DEFAULT CHARSET utf8;
-- 切换数据库
USE demo;
-- 创建用户表
CREATE TABLE IF NOT EXISTS T_USER(ID INT PRIMARY KEY,USERNAME VARCHAR(32) NOT NULL,AGE INT NOT NULL
);
-- 插入用户数据
INSERT INTO T_USER(ID, USERNAME, AGE)
VALUES(1, '张三', 20),(2, '李四', 22),(3, '王五', 24);

2、StatementUtils类

在cn.horse.demo下新建StatementUtils类

StatementUtils类：

package cn.horse.demo;import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;import java.io.InputStream;
import java.util.List;
import java.util.Objects;public abstract class StatementUtils {public static void find(String statement, Object parameter) {// 读取mybatis配置文件InputStream inputStream = ClassLoader.getSystemClassLoader().getResourceAsStream("mybatis-config.xml");// 根据配置创建SqlSession工厂SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);SqlSession sqlSession = null;try {// 创建SqlSessionsqlSession = sqlSessionFactory.openSession();// 查询用户列表List<UserInfo> userInfoList = sqlSession.selectList(statement, parameter);for (UserInfo userInfo: userInfoList) {System.out.println(userInfo);}} finally {// 关闭会话if(Objects.nonNull(sqlSession)) {sqlSession.close();}}}
}

3、UserInfo类

在cn.horse.demo下新建UserInfo类

UserInfo类：

package cn.horse.demo;public class UserInfo {private Integer id;private String name;private Integer age;@Overridepublic String toString() {StringBuilder stringBuilder = new StringBuilder();stringBuilder.append('{');stringBuilder.append("id: " + this.id);stringBuilder.append(", ");stringBuilder.append("name: " + this.name);stringBuilder.append(", ");stringBuilder.append("age: " + this.age);stringBuilder.append('}');return stringBuilder.toString();}
}

4、UserInfoMapper配置

在resources下新建demo目录，在目录下新建UserInfoMapper.xml文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.horse.demo.UserInfoMapper"><select id="findByAge" resultType="cn.horse.demo.UserInfo">SELECTID,USERNAME name,AGEFROM T_USERWHERE AGE > #{age}</select>
</mapper>

在mybatis-config.xml文件中引入UserInfoMapper.xml配置文件

<mappers><mapper resource="demo/UserInfoMapper.xml" />
</mappers>

5、启动程序

package cn.horse.demo;public class Main {public static void main(String[] args) {System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");StatementUtils.find("cn.horse.demo.UserInfoMapper.findByAge", 21);}
}

执行的结果如下：