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关于Java Webproject中web.xml文件

2017-04-18 10:28 344 查看
提及Java Webproject中web.xml文件无人不知,无人不识,呵呵呵:系统首页、servlet、filter、listener和设置session过期时限。张口就来,但是你见过该文件里的error-page标签吗?以下直接以样例的形式说明error-page标签的使用:

一个servlet文件:

package com.ghj.packageofservlet;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/**

* 有益发生异常

*

* @author GaoHuanjie

*/

public class ExceptionServlet extends HttpServlet {

private static final long serialVersionUID = -8602055287059392677L;

public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {

doPost(request, response);

}

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

Object object = null;

System.out.println(object.toString());

}

}

一个web.xml文件:

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.5"

xmlns="http://java.sun.com/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<error-page>

<error-code>404</error-code>

<location>/404.jsp</location>

</error-page>

<error-page>

<exception-type>java.lang.NullPointerException</exception-type>

<location>/exception.jsp</location>

</error-page>

<servlet>

<servlet-name>ExceptionServlet</servlet-name>

<servlet-class>com.ghj.packageofservlet.ExceptionServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>ExceptionServlet</servlet-name>

<url-pattern>/ExceptionServlet</url-pattern>

</servlet-mapping>

</web-app>

一个404页面:

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"
isErrorPage="true"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<title>404页面</title>

<style type="text/css">

a:link {

color: #555555;

text-decoration: none

}

a:visited {

color: #555555;

text-decoration: none

}

a:active {

color: #555555;

text-decoration: none

}

a:hover {

color: #6f9822;

text-decoration: none

}

.text {

font-size: 12px;

color: #555555;

font-family: "";

text-decoration: none

}

</style>

</head>

<body>

<table height="100%" cellSpacing="0" cellPadding="0" width="100%" align="center" border="0">

<tbody>

<tr>

<td valign="middle" align="center">

<table cellSpacing="0" cellPadding="0" width="500" align="center" border="0">

<tr>

<td width="17" height="17"><img height="17" src="images/co_01.gif" width="17"></td>

<td width="316" background="images/bg01.gif"></td>

<td width="17" height="17"><img height="17" src="images/co_02.gif" width="17"></td>

</tr>

<tr>

<td background="images/bg02.gif"></td>

<td>

<table class="text" cellSpacing="0" cellPadding="10" width="100%" align="center" border="0">

<tr>

<td>

<table cellSpacing="0" cellPadding="0" width="100%" border="0">

<tr>

<td><img height="66" src="images/404error.gif" width="400"></td>

</tr>

</table>

</td>

</tr>

<tr>

<td>

<table class="text" cellSpacing="0" cellPadding="0" width="100%" border="0">

<tr>

<td>

<p>

<strong><font color="#ba1c1c">HTTP404错误:</font></strong>

没有找到您要訪问的页面,请与管理员联系。

</p>

<div align="right">管理员QQ:845129726 </div>

</td>

</tr>

</table>

</td>

</tr>

</table>

</td>

<td background="images/bg03.gif"></td>

</tr>

<tr>

<td width="17" height="17"><img height="17" src="images/co_03.gif" width="17"></td>

<td background="images/bg04.gif" height="17"></td>

<td width="17" height="17"><img height="17" src="images/co_04.gif" width="17"></td>

</tr>

</table>

</td>

</tr>

</tbody>

</table>

</body>

</html>

一个处理异常页面:

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" isErrorPage="true"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<title>异常页面</title>

</head>

<body>

<table cellSpacing="0" width="600" align="center" border="0" cellpadding="0" style="margin-top: 18%">

<tbody>

<tr>

<td valign="top" align="center"><img height="100" src="images\exception.png" width="100" border="0"></td>

<td>

<font style="font-size: 10pt;color: #842b00;">HTTP错误 505:系统出现异常,暂停服务。</font>

</td>

</tr>

</tbody>

</table>

</body>

</html>

project说明:

本project用于演示web.xml文件里error-page标签的使用

本project编码方式:UTF-8

演示说明:

①、http://localhost:8080/test/index.jsp ——>演示404页面

②、http://localhost:8080/test/ExceptionServlet ——>演示异常页面

③、注意上面红底处的代码

④、假设把上面两个页面(一个404页面和一个处理异常页面)的代码非常简洁(比方body标签中就一句30或40个字符的话),在IE浏览器中进行上面訪问。你会发现页面显示的是IE浏览器自身的“报错”页面,如何使用自己的网页呢,最好的办法是在含有红底处代码的前提下添加页面的大小!

下载源代码
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