Log4j配备及应用实例

Log4j配置及应用实例

1、编写log4j配置文件(如log.config)：
# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, FILE
log4j.rootCategory=INFO, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.Threshold=INFO
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=- %m%n

# LOGFILE is set to be a File appender using a PatternLayout.
#WORKDIR setted by system.setProperty!
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=${WORKDIR}/log/adapter.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.Threshold=INFO
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

2、使用LogServlet初始化log4j的配置参数：
package com.cait.adapter.servlet;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;

import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;

public class LogServlet extends HttpServlet {

?/**
? *
? */
?private static final long serialVersionUID = -1837292475877367091L;

?static Logger logger = Logger.getLogger(LogServlet.class);

?public LogServlet() {
?}

?public void init(ServletConfig sc) throws ServletException {

??String prefix = "";
??if (sc != null) {
???prefix = sc.getServletContext().getRealPath("/");
??} else {
???prefix = "D:/Project_java/Any3Adapter/web";
??}
??String file = sc.getInitParameter("logConfigFile");
??
??if (System.getProperty("WORKDIR") == null) {
???System.setProperty("WORKDIR", prefix);
??}
??
??Properties props = new Properties();
??try {
???FileInputStream istream = new FileInputStream(prefix + file);
???props.load(istream);
???istream.close();
???String logFile = prefix + props.getProperty("log4j.appender.file.File");// 设置路径
???props.setProperty("log4j.appender.file.File", logFile);
???PropertyConfigurator.configure(props);
??}
??catch (IOException e) {
???System.out.println("Could not read configuration file [" + file + "].");
???System.out.println("Ignoring configuration file [" + file + "].");
???return;
??}
?}

}

3、设置web.xml的servlet选项，保证配置被加载
?<servlet>
??<servlet-name>LogServlet</servlet-name>
??<servlet-class>com.cait.adapter.servlet.LogServlet</servlet-class>
??<init-param>
???<param-name>logConfigFile</param-name>
???<param-value>WEB-INF/config/log.config</param-value>
??</init-param>
??<load-on-startup>1</load-on-startup>
?</servlet>

4、测试用例：
....
???Logger log=Logger.getLogger(this.getClass());
???log.info("LogServlet Test:??? testOK");