淺談在JAVA項(xiàng)目中LOG4J的使用
一、直接使用:
//輸出到項(xiàng)目文件夾下output1.txt文件中
//////////////////////////////
// DEBUG - Here is some DEBUG
// INFO - Here is some INFO
// WARN - Here is some WARN
// ERROR - Here is some ERROR
// FATAL - Here is some FATAL
//////////////////////////////
package hunnu.sanha.test;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.SimpleLayout;
import org.apache.log4j.FileAppender;
public class Simpandfile {
static Logger logger = Logger.getLogger(Simpandfile.class);
public static void main(String args[]) {
SimpleLayout layout = new SimpleLayout();
FileAppender appender = null;
try {
appender = new FileAppender(layout,"output1.txt",false);
} catch(Exception e) {}
logger.addAppender(appender);
logger.setLevel((Level) Level.);
logger.debug("Here is some DEBUG");
logger.info("Here is some INFO");
logger.warn("Here is some WARN");
logger.error("Here is some ERROR");
logger.fatal("Here is some FATAL");
}
}
//按格式輸出到項(xiàng)目文件夾下output2.html
package hunnu.sanha.test;
import java.io.*;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.HTMLLayout;
import org.apache.log4j.WriterAppender;
public class Htmlandwrite {
static Logger logger = Logger.getLogger(Htmlandwrite.class);
public static void main(String args[]) {
HTMLLayout layout = new HTMLLayout();
WriterAppender appender = null;
try {
FileOutputStream output = new FileOutputStream("output2.html");
appender = new WriterAppender(layout,output);
} catch(Exception e) {}
logger.addAppender(appender);
logger.setLevel((Level) Level.);
logger.debug("Here is some DEBUG");
logger.info("Here is some INFO");
logger.warn("Here is some WARN");
logger.error("Here is some ERROR");
logger.fatal("Here is some FATAL");
}
}
//輸出到控制臺(tái)
////////////////////////////////////////////////////////////////////////////////////////////////////////////
Milliseconds since program start: 0
Classname of caller: hunnu.sanha.test.Consandpatt
Date in ISO8601 format: 2008-07-29 11:02:30,578
Location of log event: hunnu.sanha.test.Consandpatt.main(Consandpatt.java:20)
Message: Here is some DEBUG
Milliseconds since program start: 15
Classname of caller: hunnu.sanha.test.Consandpatt
Date in ISO8601 format: 2008-07-29 11:02:30,593
Location of log event: hunnu.sanha.test.Consandpatt.main(Consandpatt.java:21)
Message: Here is some INFO
Milliseconds since program start: 15
Classname of caller: hunnu.sanha.test.Consandpatt
Date in ISO8601 format: 2008-07-29 11:02:30,593
Location of log event: hunnu.sanha.test.Consandpatt.main(Consandpatt.java:22)
Message: Here is some WARN
Milliseconds since program start: 15
Classname of caller: hunnu.sanha.test.Consandpatt
Date in ISO8601 format: 2008-07-29 11:02:30,593
Location of log event: hunnu.sanha.test.Consandpatt.main(Consandpatt.java:23)
Message: Here is some ERROR
Milliseconds since program start: 15
Classname of caller: hunnu.sanha.test.Consandpatt
Date in ISO8601 format: 2008-07-29 11:02:30,593
Location of log event: hunnu.sanha.test.Consandpatt.main(Consandpatt.java:24)
Message: Here is some FATAL
///////////////////////////////////////////////////////
package hunnu.sanha.test;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.PatternLayout;
import org.apache.log4j.ConsoleAppender;
public class Consandpatt {
static Logger logger = Logger.getLogger(Consandpatt.class);
public static void main(String args[]) {
// Note, %n is newline
String pattern = "Milliseconds since program start: %r %n";
pattern += "Classname of caller: %C %n";
pattern += "Date in ISO8601 format: %d{ISO8601} %n";
pattern += "Location of log event: %l %n";
pattern += "Message: %m %n %n";
PatternLayout layout = new PatternLayout(pattern);
ConsoleAppender appender = new ConsoleAppender(layout);
logger.addAppender(appender);
logger.setLevel((Level) Level.);
logger.debug("Here is some DEBUG");
logger.info("Here is some INFO");
logger.warn("Here is some WARN");
logger.error("Here is some ERROR");
logger.fatal("Here is some FATAL");
}
}
二、使用配置文件(都直接放到項(xiàng)目文件夾下)
//xmllog4jconfig.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
<appender name="appender" class="org.apache.log4j.FileAppender">
<param name="File" value="Indentify-Log.txt"/>
<param name="Append" value="false"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%d [%t] %p - %m%n"/>
</layout>
</appender>
<root>
<priority value ="debug"/>
<appender-ref ref="appender"/>
</root>
</log4j:configuration>
//Externalxmltest.java
package hunnu.sanha.external;
import org.apache.log4j.Logger;
import org.apache.log4j.xml.DOMConfigurator;
public class Externalxmltest {
static Logger logger = Logger.getLogger(Externalxmltest.class);
public static void main(String args[]) {
DOMConfigurator.configure("xmllog4jconfig.xml");
logger.debug("Here is some DEBUG");
logger.info("Here is some INFO");
logger.warn("Here is some WARN");
logger.error("Here is some ERROR");
logger.fatal("Here is some FATAL");
}
}
//結(jié)果輸出到Indentify-Log.txt文件中
2008-07-29 10:48:11,375 [main] DEBUG - Here is some DEBUG
2008-07-29 10:48:11,375 [main] INFO - Here is some INFO
2008-07-29 10:48:11,375 [main] WARN - Here is some WARN
2008-07-29 10:48:11,375 [main] ERROR - Here is some ERROR
2008-07-29 10:48:11,375 [main] FATAL - Here is some FATAL
// plainlog4jconfig.txt
# initialise root logger with level DEBUG and call it BLAH
log4j.rootLogger=DEBUG, BLAH
# add a ConsoleAppender to the logger BLAH
log4j.appender.BLAH=org.apache.log4j.ConsoleAppender
# set set that layout to be SimpleLayout
log4j.appender.BLAH.layout=org.apache.log4j.SimpleLayout
//Externalplaintest.java
package hunnu.sanha.external;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;
public class Externalplaintest {
static Logger logger = Logger.getLogger(Externalplaintest.class);
public static void main(String args[]) {
PropertyConfigurator.configure("plainlog4jconfig.txt");
logger.debug("Here is some DEBUG");
logger.info("Here is some INFO");
logger.warn("Here is some WARN");
logger.error("Here is some ERROR");
logger.fatal("Here is some FATAL");
}
}
//結(jié)果輸出到控制臺(tái)
DEBUG - Here is some DEBUG
INFO - Here is some INFO
WARN - Here is some WARN
ERROR - Here is some ERROR
FATAL - Here is some FATAL
附加:
2.1. 日志信息的優(yōu)先級(jí)
分為OFF、FATAL、ERROR、WARN、INFO、DEBUG、ALL或者您定義的級(jí)別。
Log4j建議只使用四個(gè)級(jí)別,優(yōu)先級(jí)從高到低分別是ERROR、WARN、INFO、DEBUG。通過在這里定義的級(jí)別,您可以控制到應(yīng)用程序中相應(yīng)級(jí)別的日志信息的開關(guān)。
假如在一個(gè)級(jí)別為q的Logger中發(fā)生一個(gè)級(jí)別為p的日志請(qǐng)求,如果p>=q,那么請(qǐng)求將被啟用。這是Log4j的核心原則。
比如在這里定義了INFO級(jí)別,則應(yīng)用程序中所有DEBUG級(jí)別的日志信息將不被打印出來;
2.2. 輸出源的使用
有選擇的能用或者禁用日志請(qǐng)求僅僅是Log4j的一部分功能。Log4j允許日志請(qǐng)求被輸出到多個(gè)輸出源。用Log4j的話說,一個(gè)輸出源被稱做一個(gè)Appender。
Appender包括console(控制臺(tái)), files(文件), GUI components(圖形的組件), remote socket servers(socket 服務(wù)), JMS(java信息服務(wù)), NT Event Loggers(NT的事件日志), and remote UNIX Syslog daemons(遠(yuǎn)程UNIX的后臺(tái)日志服務(wù))。它也可以做到異步記錄。
一個(gè)logger可以設(shè)置超過一個(gè)的appender。
用addAppender 方法添加一個(gè)appender到一個(gè)給定的logger。對(duì)于一個(gè)給定的logger它每個(gè)生效的日志請(qǐng)求都被轉(zhuǎn)發(fā)到該logger所有的appender上和該logger的父輩logger的appender上。
2.2.1. ConsoleAppender
如果使用ConsoleAppender,那么log信息將寫到Console。效果等同于直接把信息打印到System.out上了。
2.2.2. FileAppender
使用FileAppender,那么log信息將寫到指定的文件中。這應(yīng)該是比較經(jīng)常使用到的情況。
相應(yīng)地,在配置文件中應(yīng)該指定log輸出的文件名。如下配置指定了log文件名為dglog.txt
log4j.appender.A2.File=dglog.txt
注意將A2替換為具體配置中Appender的別名。
2.2.3. DailyRollingAppender
使用FileAppender可以將log信息輸出到文件中,但是如果文件太大了讀起來就不方便了。這時(shí)就可以使用DailyRollingAppender。DailyRollingAppender可以把Log信息輸出到按照日期來區(qū)分的文件中。配置文件就會(huì)每天產(chǎn)生一個(gè)log文件,每個(gè)log文件只記錄當(dāng)天的log信息:
log4j.appender.A2=org.apache.log4j.DailyRollingFileAppender
log4j.appender.A2.file=dglog
log4j.appender.A2.DatePattern='.'yyyy-MM-dd
log4j.appender.A2.layout=org.apache.log4j.PatternLayout
log4j.appender.A2.layout.ConversionPattern= %5r %-5p %c{2} - %m%n
2.2.4. org.apache.log4j.RollingFileAppender
文件大小到達(dá)指定尺寸的時(shí)候產(chǎn)生一個(gè)新的文件。
log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File= ../logs/dglog.log
# Control the maximum log file size
log4j.appender.R.MaxFileSize=100KB
# Archive log files (one backup file here)
log4j.appender.R.MaxBackupIndex=1
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n
這個(gè)配置文件指定了輸出源R,是一個(gè)輪轉(zhuǎn)日志文件。最大的文件是100KB,當(dāng)一個(gè)日志文件達(dá)到最大尺寸時(shí),Log4J會(huì)自動(dòng)把example.log重命名為dglog.log.1,然后重建一個(gè)新的dglog.log文件,依次輪轉(zhuǎn)。
2.2.5. org.apache.log4j.WriterAppender
將日志信息以流格式發(fā)送到任意指定的地方。
2.3. Layout的配置
Layout指定了log信息輸出的樣式。
2.3.1. 布局樣式
org.apache.log4j.HTMLLayout(以HTML表格形式布局),
org.apache.log4j.PatternLayout(可以靈活地指定布局模式),
org.apache.log4j.SimpleLayout(包含日志信息的級(jí)別和信息字符串),
org.apache.log4j.TTCCLayout(包含日志產(chǎn)生的時(shí)間、線程、類別等等信息)
2.3.2. 格式
%m 輸出代碼中指定的消息
%p 輸出優(yōu)先級(jí),即DEBUG,INFO,WARN,ERROR,F(xiàn)ATAL
%r 輸出自應(yīng)用啟動(dòng)到輸出該log信息耗費(fèi)的毫秒數(shù)
%c 輸出所屬的類目,通常就是所在類的全名
%t 輸出產(chǎn)生該日志事件的線程名
%n 輸出一個(gè)回車換行符,Windows平臺(tái)為"rn",Unix平臺(tái)為"n"
%d 輸出日志時(shí)間點(diǎn)的日期或時(shí)間,默認(rèn)格式為ISO8601,也可以在其后指定格式,比如:%d{yyy MMM dd HH:mm:ss,SSS},輸出類似:2002年10月18日 22:10:28,921
%l 輸出日志事件的發(fā)生位置,包括類目名、發(fā)生的線程,以及在代碼中的行數(shù)。舉例:Testlog4.main(Test Log4.java:10)
2.3.3. 例子
例子1:顯示日期和log信息
log4j.appender.A2.layout=org.apache.log4j.PatternLayout
log4j.appender.A2.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss,SSS} %m%n
打印的信息是:
2002-11-12 11:49:42,866 SELECT * FROM Role WHERE 1=1 order by createDate desc
例子2:顯示日期,log發(fā)生地方和log信息
log4j.appender.A2.layout=org.apache.log4j.PatternLayout
log4j.appender.A2.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss,SSS} %l "#" %m%n
2002-11-12 11:51:46,313 cn.net.unet.weboa.system.dao.RoleDAO.select(RoleDAO.java:409) "#"
SELECT * FROM Role WHERE 1=1 order by createDate desc
例子3:顯示log級(jí)別,時(shí)間,調(diào)用方法,log信息
log4j.appender.A2.layout=org.apache.log4j.PatternLayout
log4j.appender.A2.layout.ConversionPattern=[%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS}
method:%l%n%m%n
log信息:
[DEBUG] 2002-11-12 12:00:57,376
method:cn.net.unet.weboa.system.dao.RoleDAO.select(RoleDAO.java:409)
SELECT * FROM Role WHERE 1=1 order by createDate desc
2.4. 配置文件的例子:
log4j.rootLogger=DEBUG
#將DAO層log記錄到DAOLog,allLog中
log4j.logger.DAO=DEBUG,A2,A4
#將邏輯層log記錄到BusinessLog,allLog中
log4j.logger.Businesslog=DEBUG,A3,A4
#A1--打印到屏幕上
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-5p [%t] %37c %3x - %m%n
#A2--打印到文件DAOLog中--專門為DAO層服務(wù)
log4j.appender.A2=org.apache.log4j.DailyRollingFileAppender
log4j.appender.A2.file=DAOLog
log4j.appender.A2.DatePattern='.'yyyy-MM-dd
log4j.appender.A2.layout=org.apache.log4j.PatternLayout
log4j.appender.A2.layout.ConversionPattern=[%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS}
method:%l%n%m%n
#A3--打印到文件BusinessLog中--專門記錄邏輯處理層服務(wù)log信息
log4j.appender.A3=org.apache.log4j.DailyRollingFileAppender
log4j.appender.A3.file=BusinessLog
log4j.appender.A3.DatePattern='.'yyyy-MM-dd
log4j.appender.A3.layout=org.apache.log4j.PatternLayout
log4j.appender.A3.layout.ConversionPattern=[%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS}
method:%l%n%m%n
#A4--打印到文件alllog中--記錄所有l(wèi)og信息
log4j.appender.A4=org.apache.log4j.DailyRollingFileAppender
log4j.appender.A4.file=alllog
log4j.appender.A4.DatePattern='.'yyyy-MM-dd
log4j.appender.A4.layout=org.apache.log4j.PatternLayout
log4j.appender.A4.layout.ConversionPattern=[%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS}
method:%l%n%m%n
以上這篇淺談在JAVA項(xiàng)目中LOG4J的使用就是小編分享給大家的全部?jī)?nèi)容了,希望能給大家一個(gè)參考,也希望大家多多支持腳本之家。
相關(guān)文章
SpringBoot搭建多數(shù)據(jù)源的實(shí)現(xiàn)方法
說起多數(shù)據(jù)源,一般都來解決那些問題呢,主從模式或者業(yè)務(wù)比較復(fù)雜需要連接不同的分庫來支持業(yè)務(wù)。本文主要介紹了SpringBoot搭建多數(shù)據(jù)源的實(shí)現(xiàn)方法,感興趣的可以了解一下,感興趣的可以額了解一下2021-12-12
eclipse自動(dòng)創(chuàng)建SpringBoot項(xiàng)目報(bào)錯(cuò)的解決
這篇文章主要介紹了eclipse自動(dòng)創(chuàng)建SpringBoot項(xiàng)目報(bào)錯(cuò)的解決方式,具有很好的參考價(jià)值,希望對(duì)大家有所幫助,如有錯(cuò)誤或未考慮完全的地方,望不吝賜教2024-01-01
淺談java中為什么實(shí)體類需要實(shí)現(xiàn)序列化
下面小編就為大家?guī)硪黄獪\談java中為什么實(shí)體類需要實(shí)現(xiàn)序列化。小編覺得挺不錯(cuò)的,現(xiàn)在就分享給大家,也給大家做個(gè)參考。一起跟隨小編過來看看吧2017-05-05
JavaEE實(shí)現(xiàn)前后臺(tái)交互的文件上傳與下載
這篇文章主要介紹了JavaEE實(shí)現(xiàn)前后臺(tái)交互的文件上傳與下載,分享相關(guān)技術(shù),實(shí)現(xiàn)文件上傳下載功能,需要的朋友可以參考下2015-11-11
Spring?Boot實(shí)現(xiàn)多數(shù)據(jù)源連接和切換的解決方案
文章介紹了在SpringBoot中實(shí)現(xiàn)多數(shù)據(jù)源連接和切換的幾種方案,并詳細(xì)描述了一個(gè)使用AbstractRoutingDataSource的實(shí)現(xiàn)步驟,感興趣的朋友一起看看吧2025-01-01

