记录:MyBatis整合Log4j

本文详细介绍了如何在MyBatis项目中配置和使用日志,包括创建数据库、搭建项目框架、配置mybatis核心文件、启用log4j日志系统,以及编写测试代码。通过日志,开发者可以清晰地查看SQL语句及参数,便于调试和优化。文章还展示了log4j.properties的配置,以及不同日志实现的选择,如STDOUT_LOGGING和LOG4J。

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MyBatis日志操作

为方便我们后端程序猿观察我们的MyBatis所封装的SQL语句,可以使用MyBatis提供的日志处理。
下面,我们来快速搭建一个MyBatis的项目来实现日志的使用:Lets‘ get it!!!

第一步:准备数据

首先在Oracle里创建一个Student的数据库,如下所示

create table STUDENT(
	id number(10) primary key,
	name varchar2(30) not null,
	email varchar2(30) not null,
	age number(10) not null
)

在往数据库中插入几条数据
在这里插入图片描述

第二步:搭建项目框架并导入依赖

2.1 项目框架

在Eclipse里创建一个Java项目/Maven项目,这里为了演示就使用创建的普通的Java项目,项目目录如下所示:
在这里插入图片描述

2.2 项目jar包

在这里插入图片描述

第三步: 编写db.properties

在这里插入图片描述

第四步:编写mybatis核心配置文件

<?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">
<!--核心配置文件 -->
<configuration>
	<!--资源引入 -->
	<properties resource="db.properties"></properties>
	<!--设置信息(配置) -->
	<settings>
		<!-- <setting name="logImpl" value="STDOUT_LOGGING"/> -->
		<setting name="logImpl" value="LOG4J" /> 
		<setting name="mapUnderscoreToCamelCase" value="true" />
	</settings>
	<!--设置别名 -->
	<typeAliases>
		<!--扫描一个包 -->
		<package name="com.wei.pojo"></package>
	</typeAliases>
	<!--环境(可以配置多个) -->
	<environments default="development">
		<!--开发时的环境 -->
		<environment id="development">
			<!--事务管理 -->
			<transactionManager type="JDBC" />
			<dataSource type="POOLED">
				<!--数据库相关 -->
				<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>
	</environments>
	<!--每一个mapper需要在mybatis核心配置文件中注册 -->
	<mappers>
		<!-- 使用resource加载映射文件 -->
		<!-- <mapper resource="com/wei/mapper/StudentMapper.xml"></mapper>
		<mapper resource="com/wei/mapper/EmployeeMapper.xml"></mapper>
		<mapper resource="com/wei/mapper/DeptMapper.xml"></mapper>
		<mapper resource="com/wei/mapper/EmpMapper.xml"></mapper> -->
		
		<!-- 使用package方式加载 -->
		<package name="com.wei.mapper"></package>
	</mappers>

</configuration>

**注意:**使用日志,需要在Setting标签里写一个name属性里注入logImpl的属性值,

其值的可填项:注意严格大小写区分!!!
在这里插入图片描述

  • STDOUT_LOGGING:标准的日志打印输出
  • log4j:采用log4j的日志框架

第五步: 编写log4j.properties🔥🔥🔥

#将等级为DEBUG的日志信息输出到console和file这两个目的地,console和file的定义在下面的代码
log4j.rootLogger=INFO,console

#设置指定mapper包下的所有执行的输出的日志级别未DEBUG
log4j.logger.com.wei.mapper = DEBUG

#控制台输出的相关设置
log4j.appender.console = org.apache.log4j.ConsoleAppender
log4j.appender.console.Target = System.out
log4j.appender.console.Threshold=DEBUG
log4j.appender.console.layout = org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=[%c]-%m%n

#日志输出级别
log4j.logger.org.mybatis=DEBUG
log4j.logger.java.sql=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.ResultSet=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG

说明:

  • log4j.rootLogger:表示是全局的日志输出级别

    • FATAL: 致命的错误, 不是代码引起的, 而是系统故障;
    • ERROR: 错误, 代码运行发生的错误;
    • WARN: 警告, 不会影响程序运行, 但是可能存在风险;
    • INFO: 普通消息;
    • DEBUG: 调试信息;
    • TRACE: 跟踪信息, 打印出非常详细的运行过程.

以上日志级别由高到低, 可以通过调整日志级别控制哪些日志可以被打印.

  • 要求名称必须叫log4j.properties, 位置必须放在src目录下.

第六步:编写utils工具类

package com.wei.utils;

import java.io.IOException;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;


public class SessionUtils {

	private static SqlSessionFactory factory;

	static {
		try {
			factory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsReader("mybatis-config.xml"));
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	public static SqlSession getSession() throws Exception {
		SqlSession sqlSession = factory.openSession();
		return sqlSession;
	}
}

第七步:项目代码测试

7.1 POJO层

package com.wei.pojo;

public class Student {
	private int id;
	private String name;
	private String email;
	private int age;

	public Student() {
	}

	public Student(int id, String name, String email, int age) {
		super();
		this.id = id;
		this.name = name;
		this.email = email;
		this.age = age;
	}

	public Student(String name, String email, int age) {
		this.name = name;
		this.email = email;
		this.age = age;
	}

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	@Override
	public String toString() {
		return "Student [id=" + id + ", name=" + name + ", email=" + email + ", age=" + age + "]";
	}

}

7.2 Mapper层

package com.wei.mapper;

import java.util.List;
import java.util.Map;

import org.apache.ibatis.annotations.Param;

import com.wei.pojo.Student;

public interface StudentMapper {
	List<Student> queryAll();

	int insertStudentOne(Student student);

	int delStudent(@Param("id") int id);

	int updateStudentOne(Student student);

	int insertByBatch(List<Student> list);
	
	int deleteByBatch(List<Integer> list);
	
	int updateByBatch(List<Student> list);

	// 分页查询
	List<Student> queryByPage(Map<String, Object> pageParams);

	// 条件查询
	Student queryById(@Param("id") Integer id);

	// 模糊查询
	List<Student> queryByNameLike(@Param("name") String name);
}
<!DOCTYPE mapper
    PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.wei.mapper.StudentMapper">
	<cache></cache>
	<resultMap id="maps" type="student">
		<!-- 用ID的属性来映射主键字段 -->
		<id property="id" column="id" jdbcType="INTEGER" />
		<!-- 用result属性来映射其他非主属性字段 -->
		<result property="name" column="name" jdbcType="VARCHAR" />
		<result property="email" column="email" jdbcType="VARCHAR" />
		<result property="age" column="age" jdbcType="INTEGER" />
	</resultMap>

	<!-- 普通的查询集合 -->
	<select id="queryAll" resultType="com.wei.pojo.Student">
		select id ,name ,email, age
		from student
	</select>

	<!-- 分页查询 -->
	<select id="queryByPage" resultMap="maps">
		select * from (
		select
		rowP.*,rownum rn from(
		select id,name,email,age from student order by
		id
		) rowP where 1=1 and rownum &lt;= #{end}
		) where rn &gt; #{start}
	</select>

	<!-- 条件查询 -->
	<select id="queryById" parameterType="java.lang.Integer"
		resultType="student">
		select id ,name,email,age from student where id = #{id}
	</select>

	<!-- 模糊查询 -->
	<select id="queryByNameLike" parameterType="string"
		resultType="student">
		select id ,name, email,age from student where name like
		concat(concat('%',#{name}),'%')
	</select>

	<!-- 插入一条数据操作 -->
	<insert id="insertStudentOne" parameterType="student">
		insert into
		student(id,name,email,age)
		values(seq_stu_id.nextval,#{name},#{email},#{age})
	</insert>

	<!-- 修改一条数据 -->
	<update id="updateStudentOne" parameterType="student">
		update student
		<set>
			<if test="name!=null">
				name=#{name},
			</if>
			<if test="email!=null">
				email=#{email},
			</if>
			<if test="age!=null">
				age=#{age},
			</if>
		</set>
		<where>
			id = #{id}
		</where>
	</update>

	<!-- 删除一条数据操作 -->
	<delete id="delStudent" parameterType="int">
		delete from student where
		id = #{id}
	</delete>

	<!-- 批量插入 -->
	<insert id="insertByBatch" parameterType="java.util.List">
		insert into student
		select SEQ_STU_ID.NEXTVAL,A.* from(
		<foreach collection="list" item="item" index="index"
			separator="UNION ALL">
			SELECT
			#{item.name},
			#{item.email},
			#{item.age}
			from dual
		</foreach>
		) A
	</insert>
	
	<!-- 批量删除 -->
	<delete id="deleteByBatch" parameterType="java.util.List">
		delete from student
		where id in
		<foreach collection="list" index="index" item="id" open="(" separator="," close=")">
			#{id}
		</foreach>
	</delete>
	
	<!-- 批量修改 -->
	<update id="updateByBatch" >
        <foreach collection="list" item="item" index="index" open="begin" close=";end;" separator=";">
            update student
            <set>
                <if test="item.name != null">
                    NAME = #{item.name},
                </if>
                <if test="item.email != null">
                    email = #{item.email},
                </if>
                <if test="item.age !=null">
                    AGE = #{item.age},
                </if>
            </set>
            where ID = #{item.id}
        </foreach>
    </update>
</mapper>

6.3 测试类

package com.wei.test;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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 com.wei.mapper.StudentMapper;
import com.wei.pojo.Student;
import com.wei.utils.SessionUtils;

public class MyTest {

	@Test
	public void test() throws Exception {
		String resource = "mybatis-config.xml";
		InputStream inputStream = Resources.getResourceAsStream(resource);
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
		SqlSession session = sqlSessionFactory.openSession();
		List<Student> list = session.getMapper(StudentMapper.class).queryAll();
		for (Student student : list) {
			System.out.println(student);
		}
	}

	@Test
	public void testByPage() throws Exception {
		String resource = "mybatis-config.xml";
		InputStream inputStream = Resources.getResourceAsStream(resource);
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
		SqlSession session = sqlSessionFactory.openSession();
		Map<String, Object> map = new HashMap<String, Object>();
		map.put("start", 3);
		map.put("end", 6);
		List<Student> list = session.getMapper(StudentMapper.class).queryByPage(map);
		for (Student student : list) {
			System.out.println(student);
		}
	}

	@Test
	public void testById() throws Exception {
		String resource = "mybatis-config.xml";
		InputStream inputStream = Resources.getResourceAsStream(resource);
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
		SqlSession session = sqlSessionFactory.openSession();
		Student student = session.getMapper(StudentMapper.class).queryById(24);
		System.out.println(student);
	}

	@Test
	public void testByName() throws Exception {
		String resource = "mybatis-config.xml";
		InputStream inputStream = Resources.getResourceAsStream(resource);
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
		SqlSession session = sqlSessionFactory.openSession();
		List<Student> students = session.getMapper(StudentMapper.class).queryByNameLike("ROSE");
		for (Student student : students) {
			System.out.println(student);
		}
	}

	@Test
	public void testInsertOne() throws Exception {
		SqlSession session = SessionUtils.getSession();
		Student student = new Student();
		student.setName("ROSE");
		student.setAge(23);
		student.setEmail("rose@qq.com");

		int row = session.getMapper(StudentMapper.class).insertStudentOne(student);
		if (row > 0) {
			session.commit();
			System.out.println("插入成功" + row + "条数据");
		} else {
			session.rollback();
		}
	}

	@Test
	public void testUpdateOne() throws Exception {
		SqlSession session = SessionUtils.getSession();
		Student student = new Student();
		student.setName("ROSE");
		student.setAge(25);
		student.setEmail("roseloveing@qq.com");
		student.setId(43);

		int row = session.getMapper(StudentMapper.class).updateStudentOne(student);
		if (row > 0) {
			session.commit();
			System.out.println("修改成功" + row + "条数据");
		} else {
			session.rollback();
		}
	}

	@Test
	public void testDeleteOne() throws Exception {
		SqlSession session = SessionUtils.getSession();

		int row = session.getMapper(StudentMapper.class).delStudent(44);
		if (row > 0) {
			session.commit();
			System.out.println("删除成功" + row + "条数据");
		} else {
			session.rollback();
		}
	}

	@Test
	public void testInsertByBatch() throws Exception {
		SqlSession session = SessionUtils.getSession();
		List<Student> list = new ArrayList<Student>();
		list.add(new Student("JACK", "jack@qq.com", 23));
		list.add(new Student("Jerry", "jerry@qq.com", 30));
		list.add(new Student("keppy", "keppy@qq.com", 25));
		int row = session.getMapper(StudentMapper.class).insertByBatch(list);
		if (row >= list.size()) {
			session.commit();
			System.out.println("批量插入成功" + row + "条数据");
		} else {
			session.rollback();
		}
	}

	@Test
	public void testUpdateByBatch() throws Exception {
		SqlSession session = SessionUtils.getSession();
		List<Student> list = new ArrayList<Student>();
		list.add(new Student(46, "NIKE", "nike@qq.com", 26));
		list.add(new Student(47, "Prscy", "Prscy@qq.com", 20));
		list.add(new Student(48, "robin", "robin@qq.com", 35));
		int row = session.getMapper(StudentMapper.class).updateByBatch(list);
		System.out.println(row);

		session.commit();
		System.out.println("批量修改成功" + row + "条数据");

	}

	@Test
	public void testDeleteByBatch() throws Exception {
		SqlSession session = SessionUtils.getSession();
		List<Integer> list = new ArrayList<Integer>();
		list.add(1001);
		list.add(1002);
		list.add(1003);
		int row = session.getMapper(StudentMapper.class).deleteByBatch(list);
		if (row >= list.size()) {
			session.commit();
			System.out.println("批量删除成功" + row + "条数据");
		} else {
			session.rollback();
		}
	}
}

输出结果(部分)

在这里插入图片描述

总结:

可以看出,使用Log4j的日志输出,十分的简洁,比标准的日志输出要少很多不必要的信息。可以帮助我们程序猿快速找到我们想要关注的sql以及传递的参数信息,以及最终的查询结果。

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