【IntelliJ IDEA 2019.2】java log4j 最简用法及进阶用法

电玩女神 2021-09-21 01:36 220阅读 0赞

# java log4j 最简用法 #

1.官网下载log4j jar 包。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3podW9odWkzMDczMTc2ODQ_size_16_color_FFFFFF_t_70][]

2.src同级创建并设置log4j.properties

![20200103153404854.png][]

#设置级别
    log4j.rootLogger=debug,appender1
    
    #输出到文件(这里默认为追加方式)
    log4j.appender.appender1=org.apache.log4j.FileAppender
    #设置文件输出路径
    log4j.appender.appender1.File=myproject.log
    #设置文件输出样式
    log4j.appender.appender1.layout=org.apache.log4j.TTCCLayout

测试代码：

package com.myproject.test;
    
    import org.apache.log4j.Logger;
    
    public class MyTestClass {
        private static Logger logger = Logger.getLogger(MyTestClass.class);
        public static void main(String[] args){
            System.out.println("Hello world");
            logger.info("----交易日志，日志级别info----->"+"hello world"+"<--------");
        }
    }

运行后，就会在目录下生成一个后缀为 \*.log 的日志文件。

# 进阶用法：java log4j 打日志到控制台同时打印到不同文件 #

参考自：[https://www.cnblogs.com/lfxiao/p/11418157.html][https_www.cnblogs.com_lfxiao_p_11418157.html]

log4j.properrties

#
    # Licensed to the Apache Software Foundation (ASF) under one or more
    # contributor license agreements.  See the NOTICE file distributed with
    # this work for additional information regarding copyright ownership.
    # The ASF licenses this file to You under the Apache License, Version 2.0
    # (the "License"); you may not use this file except in compliance with
    # the License.  You may obtain a copy of the License at
    #
    #    http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS,
    # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    # See the License for the specific language governing permissions and
    # limitations under the License.
    #
    
    # Set everything to be logged to the console
    log4j.rootCategory=DEBUG, console,file
    log4j.appender.console=org.apache.log4j.ConsoleAppender
    log4j.appender.console.target=System.err
    log4j.appender.console.layout=org.apache.log4j.PatternLayout
    log4j.appender.console.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss} %p %c{1}: %m%n
    
    
    log4j.appender.file = org.apache.log4j.FileAppender
    log4j.appender.file.File = test.txt
    log4j.appender.file.layout = org.apache.log4j.PatternLayout
    log4j.appender.file.layout.ConversionPattern =%d [%t] %-5p [%c] - %m%n
    
    log4j.logger.batch1=INFO,file1
    log4j.appender.file1 = org.apache.log4j.FileAppender
    log4j.appender.file1.File = test1.txt
    log4j.appender.file1.layout = org.apache.log4j.PatternLayout
    log4j.appender.file1.layout.ConversionPattern =%d [%t] %-5p [%c] - %m%n
    
    log4j.logger.batch2=INFO,file2
    log4j.appender.file2 = org.apache.log4j.FileAppender
    log4j.appender.file2.File = test2.txt
    log4j.appender.file2.layout = org.apache.log4j.PatternLayout
    log4j.appender.file2.layout.ConversionPattern =%d [%t] %-5p [%c] - %m%n

测试代码：

import org.apache.log4j.Logger;
    
    public class Test327Class extends AT_Cmd_Interface{
    	
        private static final Logger logger = Logger.getLogger(Test327Class.class); //默认log4j对象
        private static final Logger logger1=Logger.getLogger("batch1");//batch1 log4j对象
        private static final Logger logger2=Logger.getLogger("batch2"); //batch2 log4j对象
    	
        public static void main(String[] args){
            logger.info("cs");//只写到test.txt
            logger1.info("cs1");//写到test.txt和test1.txt
            logger2.info("cs2");//写到test.txt和test2.txt
        }
    }

效果：所有日志均会打印到控制台和test.txt。logger1对象打印的日志还会记录到test1.txt，logger2对象打印的日志还会记录到test2.txt

运行结果，生成3个文件，如下：

![20200103164334142.png][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3podW9odWkzMDczMTc2ODQ_size_16_color_FFFFFF_t_70]: /images/20210920/0fad3a3475e6429a92e3f32d1d22d913.png
[20200103153404854.png]: /images/20210920/a0b503ef9c624949b5c3928766b1aa44.png
[https_www.cnblogs.com_lfxiao_p_11418157.html]: https://www.cnblogs.com/lfxiao/p/11418157.html
[20200103164334142.png]: /images/20210920/9d7d88f262f2404a975388c7dd7ba757.png