Log4j简单配置

大家好，又见面了，我是你们的朋友全栈君。

Log4j是一组强大的日志组件，在项目中时常需要用它提供一些信息，这两天学习了一下它的简单配置。

第一步，我们需要导入log4j-1.2.14.jar到lib目录下

第二步，在src下建立log4j.properties文件。添加如下内容

代码语言：javascript复制

 1 log4j.properties
 2 log4j.rootLogger =INFO,stdout
 3 log4j.logger.sedion=INFO,db
 4 log4j.logger.W=WARN,W
 5 log4j.logger.E=ERROR,E
 6 
 7 #输出到控制台
 8 log4j.appender.stdout = org.apache.log4j.ConsoleAppender
 9 log4j.appender.stdout.Target = System.out
10 log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
11 log4j.appender.stdout.layout.ConversionPattern =  %d{ABSOLUTE} %5p %c{1}:%L - %m%n
12 
13 #输出WARN级别日志
14 log4j.appender.W =org.apache.log4j.RollingFileAppender
15 log4j.appender.W.File =${catalina.home}/logs/Test/Test_W.log
16 log4j.appender.W.Append =true
17 log4j.appender.W.Threshold =WARN
18 log4j.appender.W.layout = org.apache.log4j.PatternLayout
19 log4j.appender.W.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss}  [ %t:%r ] - [ %p ]  %m%n
20 
21 #输出ERROR级别日志
22 log4j.appender.E = org.apache.log4j.RollingFileAppender
23 log4j.appender.E.File = ${catalina.home}/logs/Test/Test_E.log
24 log4j.appender.E.Append = true
25 log4j.appender.E.layout = org.apache.log4j.PatternLayout
26 log4j.appender.E.layout.ConversionPattern =%-d{yyyy-MM-dd HH:mm:ss}  [ %t:%r ] - [ %p ]  %m%n
27  
28 #######################
29  
30 # JDBC Appender  
31  
32 ####################### 
33 log4j.appender.db=org.apache.log4j.jdbc.JDBCAppender
34 log4j.appender.db.BufferSize=1
35 log4j.appender.db.driver=com.mysql.jdbc.Driver
36 log4j.appender.db.URL=jdbc:mysql://localhost:3306/test
37 log4j.appender.db.user=root
38 log4j.appender.db.password=123
39 log4j.appender.db.sql=insert into operate_log(class,method,createtime,loglevel,logmsg,username) values ("%C","%M","%d{yyyy-MM-dd HH:mm:ss}","%p","%m","%X{username}")

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40 log4j.appender.db.layout=org.apache.log4j.PatternLayout

新建一个数据库test和一张日志表operate_log。

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可以看到数据库中有个username动态字段，所以我们要写个过滤器

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 1 package config.filter;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.Filter;
 6 import javax.servlet.FilterChain;
 7 import javax.servlet.FilterConfig;
 8 import javax.servlet.ServletException;
 9 import javax.servlet.ServletRequest;
10 import javax.servlet.ServletResponse;
11 import javax.servlet.http.HttpServletRequest;
12 
13 import org.apache.log4j.MDC;
14 
15 
16 public class Log4jFilter implements Filter
17 {
18     private final static int DEDAULT_USERID = 0;
19     public void destroy()
20     {
21         
22     }
23 
24     public void doFilter(ServletRequest req, ServletResponse rep,
25             FilterChain chain) throws IOException, ServletException 
26     {
27         HttpServletRequest request = (HttpServletRequest)req;
28         String username = request.getParameter("username");
29         
30         if(username == null)
31         {
32             MDC.put("username", DEDAULT_USERID);
33         }
34         else
35         {                    
36                 System.out.println("登陆名--" username);
37                 MDC.put("username", username);            
38         }
39         
40         
41         chain.doFilter(req, rep);
42     }
43 
44     public void init(FilterConfig arg0) throws ServletException 
45     {
46         
47     }
48 
49 
50 }

然后需要在web.xml中进行log4j.properties和过滤器的配置.

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<!-- log4j配置 -->
    <context-param>
        <param-name>log4jConfigLocation</param-name>
        <param-value>classpath:log4j.properties</param-value>
    </context-param>
 
    <listener>
       <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
    </listener>
    <!-- 过滤器配置 -->
     <filter> 
        <filter-name>LogResFilter</filter-name> 
        <filter-class>config.filter.Log4jFilter</filter-class> 
    </filter>
    <filter-mapping>
        <filter-name>LogResFilter</filter-name>
        <url-pattern>*.do</url-pattern>
    </filter-mapping>

第三步，至此我们配置已经全部完成，简单写个登陆来验证一下。

jsp页面很简单，代码便不列出来了.

写个登陆实现类.

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package sedion.zhr.controller;

import java.util.List;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.log4j.Logger;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import sedion.zhr.beans.UserBean;
import sedion.zhr.service.iml.UserServiceIml;

@Controller
@RequestMapping("/action")
public class LoginController 
{
    
    private static final Logger log_w= Logger.getLogger("W");
    private static final Logger log_e = Logger.getLogger("E");
    private Log logger = LogFactory.getLog(this.getClass());  
    
    @Resource(name = "UserService")
    private UserServiceIml serviceIml;
 
    @RequestMapping("/login.do")
    public String login(UserBean bean,HttpServletRequest request,HttpServletResponse response) throws Exception
    {
         
        List<UserBean> beans = this.serviceIml.finduser(new String[]{bean.getUsername(),bean.getPassword()});
     
        if(!beans.isEmpty())
        {            
            log_w.warn("登陆成功--");
            logger.info("登陆成功");

            return "/index";
        }
        else
        {
            log_e.error("登陆失败--");            
            logger.error("登陆失败");
            return "/login";
        }
      
    }

}

将项目配置到tomcat上，启动项目.

可以看到在安装tomcat文件夹下的logs文件夹里面出现个Test文件夹，里面有两个文本，初始大小都是0kb.