spring项目中日志应该如何写？（spring+log4j）

向右看齐 2024-02-19 20:15 34阅读 0赞

日志打印是一个项目中必不可少的部分，没有日志打印，我们的代码的可维护性将会非常的差，为了能让我们的代码便于自己调试也便于别人维护，所以在项目中必须要打印日志，所以此文要解决的问题就是在spring项目中如何配置log日志。

1.首先目录结构是这样的：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW9saXViYW8x_size_16_color_FFFFFF_t_70][]

注：红色标注的部分为运行项目后实际生成的log文件

2.pom文件是这样的

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.zlb.springaop</groupId>
        <artifactId>spring-aop</artifactId>
        <version>1.0-SNAPSHOT</version>
    
        <dependencies>
            
            
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</artifactId>
                <version>5.1.8.RELEASE</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-core</artifactId>
                <version>5.1.8.RELEASE</version>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-beans</artifactId>
                <version>5.1.8.RELEASE</version>
            </dependency>
    
            
            
            <dependency>
                <groupId>aopalliance</groupId>
                <artifactId>aopalliance</artifactId>
                <version>1.0</version>
            </dependency>
            
            <dependency>
                <groupId>aspectj</groupId>
                <artifactId>aspectjrt</artifactId>
                <version>1.5.4</version>
            </dependency>
    
            
            <dependency>
                <groupId>org.aspectj</groupId>
                <artifactId>aspectjweaver</artifactId>
                <version>1.9.4</version>
            </dependency>
    
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>1.2.17</version>
            </dependency>
    
        </dependencies>
    
    
    </project>

注意：

aopalliance依赖一定不能少，如果少了就会报如下异常

org.springframework.beans.factory.BeanCreationExcspring-aopeption: Error creating bean with name 'org.springframework.aop.config.internalAutoProxyCreator': Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springframework.aop.aspectj.annotation.AnnotationAwareAspectJAutoProxyCreator]: Constructor threw exception; nested exception isJava.lang.NoClassDefFoundError: org/aopalliance/intercept/MethodInterceptor

3.log4j.xml文件这样写

<?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">
    		<layout class="org.apache.log4j.PatternLayout">
    			<param name="ConversionPattern" value="[%p][%d{ISO8601}][%t][%c][%m]%n" />
    		</layout>
    	</appender>
    
    	
    	<appender name="DEBUG" class="org.apache.log4j.RollingFileAppender">
    		
    		<param name="File" value="springaop/log/debug/app-debug.log" />
    		
    		<param name="Append" value="true" />
    		
    		
    		<param name="MaxFileSize" value="30MB" />
    		
    		<param name="MaxBackupIndex" value="30" />
    		
    		<param name="Encoding" value="UTF8" />
    		
    		<layout class="org.apache.log4j.PatternLayout">
    			<param name="ConversionPattern" value="[%p][%d{ISO8601}][%t][%c][%m]%n" />
    		</layout>
    		
    		
    		<filter class="org.apache.log4j.varia.LevelRangeFilter">
    			<param name="LevelMin" value="DEBUG" />
    			<param name="LevelMax" value="DEBUG" />
    		</filter>
    	</appender>
    
    	<appender name="INFO" class="org.apache.log4j.RollingFileAppender">
    		<param name="File" value="springaop/log/debug/app-debug.log" />
    		
    		<param name="Append" value="true" />
    		<param name="MaxFileSize" value="30MB" />
    		<param name="MaxBackupIndex" value="30" />
    		<param name="Encoding" value="UTF8" />
    		<layout class="org.apache.log4j.PatternLayout">
    			<param name="ConversionPattern" value="[%p][%d{ISO8601}][%t][%c][%m]%n" />
    		</layout>
    		<filter class="org.apache.log4j.varia.LevelRangeFilter">
    			<param name="LevelMin" value="INFO" />
    			<param name="LevelMax" value="INFO" />
    		</filter>
    	</appender>
    
    	<appender name="WARN" class="org.apache.log4j.RollingFileAppender">
    		<param name="File" value="springaop/log/debug/app-debug.log" />
    		<param name="Append" value="true" />
    		<param name="MaxFileSize" value="30MB" />
    		<param name="MaxBackupIndex" value="30" />
    		<param name="Encoding" value="UTF8" />
    		<layout class="org.apache.log4j.PatternLayout">
    			<param name="ConversionPattern" value="[%p][%d{ISO8601}][%t][%c][%m]%n" />
    		</layout>
    		<filter class="org.apache.log4j.varia.LevelRangeFilter">
    			<param name="LevelMin" value="WARN" />
    			<param name="LevelMax" value="WARN" />
    		</filter>
    	</appender>
    
    	<appender name="ERROR" class="org.apache.log4j.RollingFileAppender">
    		<param name="File" value="springaop/log/debug/app-debug.log" />
    		
    		<param name="Append" value="true" />
    		<param name="MaxFileSize" value="30MB" />
    		<param name="MaxBackupIndex" value="30" />
    		<param name="Encoding" value="UTF8" />
    		<layout class="org.apache.log4j.PatternLayout">
    			<param name="ConversionPattern" value="[%p][%d{ISO8601}][%t][%c][%m]%n" />
    		</layout>
    		<filter class="org.apache.log4j.varia.LevelRangeFilter">
    			<param name="LevelMin" value="ERROR" />
    			<param name="LevelMax" value="ERROR" />
    		</filter>
    	</appender>
    
    	<logger name="mapper/userMapper.xml">
    		<level value="DEBUG"></level>
    		<appender-ref ref="STDOUT"></appender-ref>
    	</logger>
    	<root>
    		
    		<priority value="INFO" />
    		<appender-ref ref="STDOUT" />
    		<appender-ref ref="DEBUG" />
    		<appender-ref ref="INFO" />
    		<appender-ref ref="WARN" />
    		<appender-ref ref="ERROR" />
    	</root>
    
    </log4j:configuration>

注意：<param name="File" value="springaop/log/debug/app-debug.log" />

这就是你想要log文件写出的地址！

4.java类这样写

（1）LogAspect

package com.zlb.spring.aop;
    
    import org.apache.log4j.Logger;
    import org.aspectj.lang.JoinPoint;
    import org.aspectj.lang.annotation.*;
    import org.springframework.core.annotation.Order;
    import org.springframework.stereotype.Component;
    
    import java.util.Arrays;
    
    @Component
    @Aspect
    @Order(1)
    public class LogAspect {
        private org.apache.log4j.Logger logger = Logger.getLogger(this.getClass());
        @Pointcut("execution(public * com.zlb.spring.aop.*.*(..))")
        public  void  pointCut(){}
    
        @Before("pointCut()")
        public void doBefore(JoinPoint joinPoint){
            logger.info("class_method : " + joinPoint.getSignature().getDeclaringTypeName() + "." + joinPoint.getSignature().getName()+" start");
            logger.info("args : " + Arrays.toString(joinPoint.getArgs()));
        }
    
        @After("pointCut()")
        public void doAfter(JoinPoint joinPoint){
            logger.info("class_method : " + joinPoint.getSignature().getDeclaringTypeName() + "." + joinPoint.getSignature().getName()+" end");
        }
    
        @AfterReturning(returning ="result",value = "pointCut()")
        public void doAfterReturning(Object result){
           logger.info("returned"+result);
        }
    
        @AfterThrowing(value = "pointCut()",throwing = "exception")
        public void doAfterThrowing(Exception exception){
            logger.info("method exception"+exception.getMessage());
        }
    }

注意：

@AfterReturning与@AfterThrowing所标记的方法，参数位置不能改变！

（2）LogConfig这样写

package com.zlb.spring.aop;
    
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.context.annotation.EnableAspectJAutoProxy;
    
    @ComponentScan(value = "com.zlb.spring.aop")
    @Configuration
    @EnableAspectJAutoProxy
    public class LogConfig {
    }

注意：如果用spring注解方式开发项目，一定要使用@EnableAspectJAutoProxy注解，不然没法实现aop

（3）被测试的目标方法类这样写

package com.zlb.spring.aop;
    
    import org.springframework.stereotype.Component;
    
    @Component
    public class MathCalculator {
        public int getDiv(int x,int y){
            return x/y;
        }
    }

（4）测试类这样写

package com.zlb.spring.aop;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.annotation.AnnotationConfigApplicationContext;
    
    public class TestAop {
        public static void main(String[] args) {
            ApplicationContext applicationContext = new AnnotationConfigApplicationContext(LogConfig.class);
            System.out.println("ioc 容器舒适化完成！");
            //打印logger日志
            MathCalculator mathCalculator = applicationContext.getBean(MathCalculator.class);
            mathCalculator.getDiv(6,0);
        }
    }

运行结果长这样：

ioc 容器舒适化完成！
    [INFO][2019-06-27 19:09:15,758][main][com.zlb.spring.aop.LogAspect][class_method : com.zlb.spring.aop.MathCalculator.getDiv start]
    [INFO][2019-06-27 19:09:15,759][main][com.zlb.spring.aop.LogAspect][args : [6, 1]]
    [INFO][2019-06-27 19:09:15,787][main][com.zlb.spring.aop.LogAspect][class_method : com.zlb.spring.aop.MathCalculator.getDiv end]
    [INFO][2019-06-27 19:09:15,787][main][com.zlb.spring.aop.LogAspect][returned6]
    
    Process finished with exit code 0

思考：如果 MathCalculator mathCalculator = applicationContext.getBean(MathCalculator.class);

改成 MathCalculator mathCalculator = new MathCalculator（）还能实现日志打印吗？

答：这样是不能的，因为切面日志只能管理spring容器中的bean，而不能管理我们手动创建的bean。

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