登录API - Java日志记录API通过生成适合最终用户，系统管理员，现场服务工程师和软件开发团队进行分析的日志报告，促进了客户站点的软件服务和维护。日志API捕获信息，例如安全失败，配置错误，性能瓶颈和/或应用程序或平台中的错误。核心软件包包括支持将纯文本或XML格式的日志记录传递到内存，输出流，控制台，文件和套接字。另外，日志记录API能够与主机操作系统上已经存在的日志记录服务进行交互。
包java.util.logging «提供Java平台的核心日志记录工具的类和接口。
Log4j 1.x «log4j是流行的基于Java的日志记录实用程序。Log4j是一个基于许多作者的工作的开源项目。它允许开发人员通过使用Appenders [控制台，文件，数据库和电子邮件]控制将哪些日志语句输出到各个位置。它可以在运行时使用外部配置文件进行完全配置。
Log4j具有三个主要组件：
- 记录器 -[关闭，致命，错误，警告，信息，调试，跟踪]
追加者
- 布局-[PatternLayout，EnhancedPatternLayout]
可以使用XML或Java属性（键=值）格式编写配置文件。
- log4j_External.properties«Java属性（键=值）格式
开头“ $ { ”和结尾“ } ” 之间的字符串被解释为键。替换变量的值可以定义为系统属性或配置文件本身。设置附加器特定选项。«log4j.appender.appenderName.option = value，对于每个命名的附加程序，您都可以配置其布局。
log4j.rootLogger=INFO, FILE, FILE_PER_SIZE, FILE_PER_DAY, CONSOLE, MySql
#log.path=./
log.path=E:/Logs
# https://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/PatternLayout.html
# {%-5p - [WARN ,INFO ,ERROR], %5p 0- [ WARN, INFO,ERROR]}
log.patternLayout=org.apache.log4j.PatternLayout
log.pattern=%-5p - %d{yyyy-MM-dd HH:mm:ss.SSS} %C{1}:%12.20M:%L - %m %n
# System.out | System.err
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.Target=System.err
log4j.appender.CONSOLE.layout=${log.patternLayout}
log4j.appender.CONSOLE.layout.ConversionPattern=${log.pattern}
# File Appender
log4j.appender.FILE=org.apache.log4j.FileAppender
log4j.appender.FILE.File=${log.path}/logFile.log
#log4j:ERROR setFile(null,false) call failed. - Defaults setFile(null,true)
#log4j.appender.FILE.Append = false
log4j.appender.FILE.layout=${log.patternLayout}
log4j.appender.FILE.layout.ConversionPattern=${log.pattern}
# BackUP files for every Day.
log4j.appender.FILE_PER_DAY=org.apache.log4j.DailyRollingFileAppender
# [[ Current File ] - logRollingDayFile.log ], { [BackUPs] logRollingDayFile.log_2017-12-10, ... }
log4j.appender.FILE_PER_DAY.File=${log.path}/logRollingDayFile.log
log4j.appender.FILE_PER_DAY.DatePattern='_'yyyy-MM-dd
log4j.appender.FILE_PER_DAY.layout=${log.patternLayout}
log4j.appender.FILE_PER_DAY.layout.ConversionPattern=${log.pattern}
# BackUP files for size rotation with log cleanup.
log4j.appender.FILE_PER_SIZE=org.apache.log4j.RollingFileAppender
# [[ Current File ] - logRollingFile.log ], { [BackUPs] logRollingFile.log.1, logRollingFile.log.2}
log4j.appender.FILE_PER_SIZE.File=${log.path}/logRollingFile.log
log4j.appender.FILE_PER_SIZE.MaxFileSize=100KB
log4j.appender.FILE_PER_SIZE.MaxBackupIndex=2
log4j.appender.FILE_PER_SIZE.layout=${log.patternLayout}
log4j.appender.FILE_PER_SIZE.layout.ConversionPattern=${log.pattern}
# MySql Database - JDBCAppender
log4j.appender.MySql=org.apache.log4j.jdbc.JDBCAppender
log4j.appender.MySql.driver=com.mysql.jdbc.Driver
log4j.appender.MySql.URL=jdbc:mysql://localhost:3306/automationlab
log4j.appender.MySql.user=root
log4j.appender.MySql.password=
log4j.appender.MySql.layout=org.apache.log4j.EnhancedPatternLayout
log4j.appender.MySql.layout.ConversionPattern=INSERT INTO `logdata` VALUES ('%p', '%d{yyyy-MM-dd HH:mm:ss}', '%C', '%M', '%L', '%m');
#log4j.appender.MySql.sql=INSERT INTO `logdata` VALUES ('%p', '%d{yyyy-MM-dd HH:mm:ss}', '%C', '%M', '%L', '%m');
# Direct log events[Messages] to MongoDB Collection - MongoDbAppender
log.mongoDB.hostname=loalhost
log.mongoDB.userName=Yash777
log.mongoDB.password=Yash@123
log.mongoDB.DB=MyLogDB
log.mongoDB.Collection=Logs
log4j.appender.MongoDB=org.log4mongo.MongoDbAppender
log4j.appender.MongoDB.hostname=${log.mongoDB.hostname}
log4j.appender.MongoDB.userName=${log.mongoDB.userName}
log4j.appender.MongoDB.password=${log.mongoDB.password}
log4j.appender.MongoDB.port=27017
log4j.appender.MongoDB.databaseName=${log.mongoDB.DB}
log4j.appender.MongoDB.collectionName=${log.mongoDB.Collection}
log4j.appender.MongoDB.writeConcern=FSYNCED
表的MySQL表结构 logdata
CREATE TABLE IF NOT EXISTS `logdata` (
`Logger_Level` varchar(5) COLLATE utf8_unicode_ci NOT NULL,
`DataTime` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`ClassName` varchar(30) COLLATE utf8_unicode_ci NOT NULL,
`MethodName` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
`LineNumber` int(10) NOT NULL,
`Message` text COLLATE utf8_unicode_ci NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
- log4j_External.xml«XML log4j：使用公共DTD文件进行配置
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE log4j:configuration PUBLIC
"-//APACHE//DTD LOG4J 1.2//EN" "http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/xml/doc-files/log4j.dtd">
<log4j:configuration debug="false">
<appender name="CONSOLE" class="org.apache.log4j.ConsoleAppender">
<param name="target" value="System.out" />
<param name="threshold" value="debug" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p - %d{yyyy-MM-dd HH:mm:ss.SSS} %C{1}:%12.20M:%L - %m %n" />
</layout>
</appender>
<appender name="FILE" class="org.apache.log4j.FileAppender">
<param name="file" value="E:/Logs/logFile.log" />
<param name="append" value="false" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p - %d{yyyy-MM-dd HH:mm:ss.SSS} %C{1}:%12.20M:%L - %m %n" />
</layout>
</appender>
<appender name="FILE_PER_SIZE" class="org.apache.log4j.RollingFileAppender">
<param name="file" value="E:/Logs/logRollingFile.log" />
<param name="immediateFlush" value="true"/>
<param name="maxFileSize" value="100KB" />
<param name="maxBackupIndex" value="2"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p - %d{yyyy-MM-dd HH:mm:ss.SSS} %C{1}:%12.20M:%L - %m %n" />
</layout>
</appender>
<appender name="FILE_PER_DAY" class="org.apache.log4j.DailyRollingFileAppender">
<param name="file" value="E:/Logs/logRollingDayFile.log" />
<param name="datePattern" value="'_'yyyy-MM-dd" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p - %d{yyyy-MM-dd HH:mm:ss.SSS} %C{1}:%12.20M:%L - %m %n"/>
</layout>
</appender>
<root>
<priority value="info" />
<appender-ref ref="CONSOLE" />
<appender-ref ref="FILE" />
<appender-ref ref="FILE_PER_SIZE" />
<appender-ref ref="FILE_PER_DAY" />
</root>
</log4j:configuration>
- 从Java程序中的URL进行Log4j配置：
为了使用外部文件指定自定义配置，使用的类必须实现Configurator接口。
当默认配置文件“ log4j.properties”，“ log4j.xml”不可用时
public class LogFiles {
// Define a static logger variable so that it references the Logger instance named "LogFiles".
static final Logger log = Logger.getLogger( LogFiles.class );
@SuppressWarnings("deprecation")
public static void main(String[] args) {
System.out.println("CONFIGURATION_FILE « "+LogManager.DEFAULT_CONFIGURATION_FILE);
System.out.println("DEFAULT_XML_CONFIGURATION_FILE = 'log4j.xml' « Default access modifier");
String fileName = //"";
//"log4j_External.xml";
"log4j_External.properties";
String configurationFile = System.getProperty("user.dir")+"/src/" + fileName;
if( fileName.contains(".xml") ) {
DOMConfigurator.configure( configurationFile );
log.info("Extension *.xml");
} else if ( fileName.contains(".properties") ) {
PropertyConfigurator.configure( configurationFile );
log.info("Extension *.properties");
} else {
DailyRollingFileAppender dailyRollingAppender = new DailyRollingFileAppender();
dailyRollingAppender.setFile("E:/Logs/logRollingDayFile.log");
dailyRollingAppender.setDatePattern("'_'yyyy-MM-dd");
PatternLayout layout = new PatternLayout();
layout.setConversionPattern( "%-5p - %d{yyyy-MM-dd HH:mm:ss.SSS} %C{1}:%12.20M:%L - %m %n" );
dailyRollingAppender.setLayout(layout);
dailyRollingAppender.activateOptions();
Logger rootLogger = Logger.getRootLogger();
rootLogger.setLevel(Level.DEBUG);
rootLogger.addAppender(dailyRollingAppender);
log.info("Configuring from Java Class.");
}
log.info("Console.Message.");
method2();
methodException(0);
}
static void method2() {
log.info("method2 - Console.Message.");
}
static void methodException(int b) {
try {
int a = 10/b;
System.out.println("Result : "+ a);
log.info("Result : "+ a);
} catch (Exception ex) { // ArithmeticException: / by zero
log.error(String.format("\n\tException occurred: %s", stackTraceToString(ex)));
}
}
public static String stackTraceToString(Exception ex) {
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
ex.printStackTrace(pw);
return sw.toString();
}
}