Servlet中url-pattern詳解
阿新 • • 發佈:2018-12-31
過濾器概述
過濾器就好比應用中的保安,利用過濾器實現對請求和響應的攔截。
編寫過濾器的步驟
編寫一個類,實現javax.servlet.Filter介面
[java] view plain copy print?- package com.bjpowernode.servlet;
- import java.io.IOException;
- import javax.servlet.Filter;
- import javax.servlet.FilterChain;
- import javax.servlet.FilterConfig;
-
import
- import javax.servlet.ServletRequest;
- import javax.servlet.ServletResponse;
- publicclass FilterDemo1 implements Filter {
- //由容器呼叫:完成過濾器的初始化
- publicvoid init(FilterConfig filterConfig) throws ServletException {
- // TODO Auto-generated method stub
-
}
- //由容器呼叫,每次請求和響應都會經過該方法
- publicvoid doFilter(ServletRequest request, ServletResponse response,
- FilterChain chain) throws IOException, ServletException {
- System.out.println("FilterDemo1過濾器執行了");
- chain.doFilter(request, response); //放行,讓下一個資源執行
- }
-
//由容器呼叫:完成過濾器銷燬時的清理工作
- publicvoid destroy() {
- // TODO Auto-generated method stub
- }
- }
配置檔案 web.xml
[html] view plain copy print?- <?xmlversion="1.0"encoding="UTF-8"?>
- <web-appversion="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">
- <display-name></display-name>
- <welcome-file-list>
- <welcome-file>index.jsp</welcome-file>
- </welcome-file-list>
- <filter>
- <filter-name>FilterDemo1</filter-name>
- <filter-class>com.bjpowernode.servlet.FilterDemo1</filter-class>
- </filter>
- <filter-mapping>
- <filter-name>FilterDemo1</filter-name>
- <url-pattern>/*</url-pattern>
- </filter-mapping>
- </web-app>