log4j.properties

# 设置root logger等级为ALL，且appender有A1和FILE
log4j.rootLogger=ALL, A2

# 设置个控制台输出源，该appender名叫：A1
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n


#设置个文件输出源，该appender名叫：FILE
log4j.appender.FILE=org.apache.log4j.FileAppender
log4j.appender.FILE.file=D:/logs/log4j.log
log4j.appender.FILE.append=true
log4j.appender.FILE.layout=org.apache.log4j.PatternLayout
log4j.appender.FILE.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n


#设置个文件输出源（滚动文件输出源，按照文件大小重新生成临时文件），该appender名叫：A2
log4j.appender.A2=org.apache.log4j.RollingFileAppender
log4j.appender.A2.file=D:/logs/log4j.log
log4j.appender.A2.append=true
#maxFileSize  文件最大大小，单位是:【KB】超过会将旧的数据放在临时文件，新的日志继续打印在file指定的文件名中
log4j.appender.A2.maxFileSize=1
#maxBackupIndex  文件最大备份数，默认为1
log4j.appender.A2.maxBackupIndex=10
log4j.appender.A2.layout=org.apache.log4j.PatternLayout
log4j.appender.A2.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

测试代码

package com.example.test;

import java.io.PrintWriter;

import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.ConsoleAppender;
import org.apache.log4j.Layout;
import org.apache.log4j.Logger;
import org.apache.log4j.PatternLayout;
import org.apache.log4j.SimpleLayout;
import org.apache.log4j.spi.LoggingEvent;
import org.junit.Test;

public class TestLog4j {

	private static final Logger logger = Logger.getLogger(TestLog4j.class);
	
	@Test
	public void testFile() {
		while (true) {
			logger.fatal("fatal"); // 严重错误，一般会造成系统崩溃 和终止运行 
		}
	}
	
}

测试结果