Filter （3）【日志记录与异常捕捉】
一：
记录日志也是Filter擅长的工作之一，在request之前和之后都可以记录日志。该日志记录Filter使用 apache的日志工具记录日志，记录客户的IP地址，访问的URL以及消耗的时间。
package com.filter;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class LogFilter implements Filter {
private Log log = LogFactory.getLog(this.getClass());
private String filterName;
@Override
public void init(FilterConfig config) throws ServletException {
// 获取 Filter 的name，设置在 web-xml 中。
filterName = config.getFilterName();
log.info("自动获取 Filter :" + filterName);
}
@Override
public void doFilter(ServletRequest req, ServletResponse resp,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) req;
HttpServletResponse response = (HttpServletResponse) resp;
long startTime = System.currentTimeMillis();
String requestURI = request.getRequestURI();
// request.getQueryString() 获取查询字符串 比如客户端发送. http://localhost/test.do?a=b&c=d&e=f
// 通过request.getQueryString()得到的是 a=b&c=d&e=f ..
requestURI = request.getQueryString() == null ? requestURI : (requestURI + "?" + request.getQueryString());
chain.doFilter(request, response);
long endTime = System.currentTimeMillis();
log.info(request.getRemoteAddr() + "访问了" + requestURI + ",总共用时" + (endTime - startTime) + "毫秒");
}
@Override
public void destroy() {
// TODO Auto-generated method stub
}
}
别忘了 ： 配置文件，log4j.Properties
log4j.rootLogger=INFO, A1 log4j.appender.A1=org.apache.log4j.ConsoleAppender log4j.appender.A1.layout=org.apache.log4j.PatternLayout log4j.appender.A1.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss,SSS} [%l]-[%p] %m%n
二：异常捕获
package com.filter;
import java.io.IOException;
import javax.security.auth.login.AccountException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import com.filter.exception.BusinessException;
public class ExceptionHandlerFilter implements Filter {
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
try {
chain.doFilter(request, response);
} catch (Exception e) {
Throwable rootCause = e;// 根异常
while( rootCause.getCause() != null){
// 循环 直到寻找到根异常 为止。
rootCause = rootCause.getCause();
}
String message = rootCause.getMessage();
message = message == null ? "异常：" + rootCause.getClass().getName() : message;
request.setAttribute("message", message);
request.setAttribute("e", e);
if(rootCause instanceof AccountException) {
request.getRequestDispatcher("/accountException.jsp").forward(request, response);
}else if(rootCause instanceof BusinessException) {
request.getRequestDispatcher("/businessException.jsp").forward(request, response);
}else {
request.getRequestDispatcher("/exception.jsp").forward(request,
response);
}
}
}
@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub
}
}
<%@ page language="java" contentType="text/html; charset=UTF-8" %>
<%@ page import="com.filter.exception.AccountException" %>
<%@ page import="com.filter.exception.BusinessException" %>
<%
String action = request.getParameter("action");
if("businessException".equals(action)){
throw new BusinessException("业务操作失败 。 ");
}else if("accountException".equals(action)){
throw new AccountException("您需要登陆后再进行此项操作. ");
}else if("exception".equals(action)){
Integer.parseInt("");
}
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<a href=" ${ pageContext.request.requestURI }?action=businessException" >test businessException</a><br>
<a href=" ${ pageContext.request.requestURI }?action=accountException"> test accountException</a><br>
<a href=" ${ pageContext.request.requestURI }?action=exception">test exception</a>
</body>
</html>
<%@ page language="java" contentType="text/html; charset=UTF-8" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<style type="text/css">
.error{
font-size : 12px;
padding : 5px;
border : 1px solid #FF0000;
background : url(image/error.gif)8px 5px no-repeat #FFEEFF;
padding-left : 30px';
}
</style>
</head>
<body>
<div class="error">
${ message }<a href="javascript:history.go(-1); ">返回</a>
</div>
</body>
</html>
<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<style type="text/css">
body, td, div, input {
font-size: 12px;
}
.error {
padding: 5px;
border: 1px solid #FF0000;
background: url(images/error.gif) 8px 5px no-repeat #FFEEFF;
padding-left: 30px;
}
</style>
</head>
<body>
<div class="error">
${ message }
</div>
<form action="accountException">
<table>
<tr>
<td>账号</td>
<td>
<input type="text" name="account"/>
</td>
</tr>
<tr>
<td>密码</td>
<td>
<input type="text" name="password"/>
</td>
</tr>
<tr>
<td> </td>
<td><input type="submit" value=" 登录 " /></td>
</tr>
</table>
</form>
</body>
</html>