log4j的设置与应用

一.单独使用

1.log4j.properties

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###Setting###
log4j.rootLogger = debug,stdout,D,E,I
###Output to console###
log4j.appender.stdout = org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target = System.out
log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern = [%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n
###Output debug to debug.log###
log4j.appender.D = org.apache.log4j.DailyRollingFileAppender
log4j.appender.D.File = /home/jalenchu/jalen_chu/logs/debug.log
log4j.appender.D.Append = true
log4j.appender.D.Threshold = DEBUG
log4j.appender.D.layout = org.apache.log4j.PatternLayout
log4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n
###Output info to info.log###
log4j.appender.I = org.apache.log4j.DailyRollingFileAppender
log4j.appender.I.File = /home/jalenchu/jalen_chu/logs/info.log
log4j.appender.I.Append = true
log4j.appender.I.Threshold = INFO
log4j.appender.I.layout = org.apache.log4j.PatternLayout
log4j.appender.I.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n
###Output error to error.log###
log4j.appender.E = org.apache.log4j.DailyRollingFileAppender
log4j.appender.E.File =/home/jalenchu/jalen_chu/logs/error.log
log4j.appender.E.Append = true
log4j.appender.E.Threshold = ERROR
log4j.appender.E.layout = org.apache.log4j.PatternLayout
log4j.appender.E.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n

2.test.java

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package log4j.test;
import org.apache.log4j.Logger;
public class Log4jTest
{
private static Logger logger = Logger.getLogger(Log4jTest.class);
public static void main(String[] args)
{
logger.error("This is an error message!");
logger.info("This is an info message");
logger.debug("This is a debug message");
}
}

二.在web项目中使用,使用servlet( log4j.properties同上 )

1.web.xml

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<servlet>
<servlet-name>Log4JInitServlet</servlet-name>
<servlet-class>log4j.test.Log4JInitServlet</servlet-class>
<init-param>
<param-name>log4j-properties-location</param-name>
<param-value>/WEB-INF/classes/log4j.properties</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Log4JTestServlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>Log4JTestServlet</servlet-name>
<servlet-class>log4j.test.Log4JTestServlet</servlet-class>
</servlet>

2.Log4JInitServlet.java

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package log4j.test;
import java.io.File;
import java.io.IOException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.PropertyConfigurator;
@WebServlet("/Log4JInitServlet")
public class Log4JInitServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public Log4JInitServlet() {
super();
}
public void init(ServletConfig config) throws ServletException {
System.out.println("Log4JInitServlet 正在初始化 log4j日志设置信息");
String log4jLocation = config.getInitParameter("log4j-properties-location");
ServletContext sc = config.getServletContext();
if (log4jLocation == null) {
System.err.println("*** 没有 log4j-properties-location 初始化的文件, 所以使用 BasicConfigurator初始化");
BasicConfigurator.configure();
} else {
String webAppPath = sc.getRealPath("/");
String log4jProp = webAppPath + log4jLocation;
File yoMamaYesThisSaysYoMama = new File(log4jProp);
if (yoMamaYesThisSaysYoMama.exists()) {
System.out.println("使用: " + log4jProp + "初始化日志设置信息");
PropertyConfigurator.configure(log4jProp);
} else {
System.err.println("*** " + log4jProp + " 文件没有找到, 所以使用 BasicConfigurator初始化");
BasicConfigurator.configure();
}
}
super.init(config);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
}

3.Log4JTestServlet.java

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package log4j.test;
import java.io.IOException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;
@WebServlet("/Log4JTestServlet")
public class Log4JTestServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static Logger logger = Logger.getLogger(Log4JTestServlet.class);
public Log4JTestServlet() {
super();
}
public void init(ServletConfig config) throws ServletException {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
logger.debug("This is debug message.");
logger.info("This is info message.");
logger.error("This is error message.");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}