log4j–动态打印日志文件到指定文件夹

1、添加Maven依赖

<!-- log4j日志相关坐标 -->
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>1.7.21</version>
		</dependency>
		<!-- 这里注意：如果是springBoot项目，不必再引入下边这个jar了，
        因为spring-boot-starter本身就已经引入这个jar了。以免造成jar包冲突 -->
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-log4j12</artifactId>
			<version>1.7.21</version>
		</dependency>

2、配置文件 log4j.properties

log4j.rootLogger = debug,stdout,file

### 输出到控制台 ###
log4j.appender.stdout = org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target = System.out
log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern =  %d{ABSOLUTE} %5p %c{1}:%L - %m%n

### 输出到日志文件 ###
log4j.appender.file = org.apache.log4j.DailyRollingFileAppender

###设置DatePattern，当天日志保存到log.log文件，前一天的日志文件名将被修改为log.log + _yyyy-MM-dd.log
log4j.appender.file.File =D/logs/log.log
log4j.appender.file.DatePattern = '_'yyyy-MM-dd'.log'
log4j.appender.file.Append = true

## 输出DEBUG级别以上的日志
log4j.appender.file.Threshold = DEBUG
log4j.appender.file.layout = org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss}  [ %t:%r ] - [ %p ]  %m%n

3、编写日志打印工具类 LogUtil

package com.example.loginfo;


import org.apache.log4j.DailyRollingFileAppender;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.PatternLayout;

import java.io.File;


public class LogUtil {

    private static Logger logger;
    private static String filepath;

    public static void setLog(String path) {      //path:日志保存路径
        filepath = path;
        new File(filepath).mkdir();  //创建文件夹
    }

    public static void infoMsg(String filename, String msg) {       //filename:生成日志的文件名  msg:日志信息
        logger = Logger.getLogger("_" + filename);
        DailyRollingFileAppender appender = new DailyRollingFileAppender();
        appender.setFile(filepath + "/" + filename + ".log");
        appender.setDatePattern("'.'yyyy-MM-dd");
        PatternLayout layout = new PatternLayout("%-4r %-5p %d{yyyy-MM-dd HH:mm:ssS}%c %m%n");
        appender.setLayout(layout);
        appender.setAppend(true);
        appender.activateOptions();
        logger.addAppender(appender);
        logger.setAdditivity(false);
        logger.setLevel(Level.INFO);
        logger.info(msg);
        appender.close();
    }

    public Logger getLogger() {
        return logger;
    }
}

4、工具类调用

package com.example.loginfo;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.ArrayList;
import java.util.List;

@RestController
public class LogController {
    
    Logger logger = LoggerFactory.getLogger(LogController.class);

    @GetMapping(value = "/log")
    public void testLog() {
        LogUtil.setLog("E:\\home\\cuiyudong");
        List<Object> objects = new ArrayList<>();
        objects.add("FHIUFWIEU");
        objects.add("DASD");
        objects.add("FHIUCASFFGFWIEU");

        LogUtil.infoMsg("LogController日至信息：",objects.toString());
    }
}

测试结果：