Servlet_03

2019-11-09 17:20:41

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過濾器步驟：/** * 過濾器 * 1、創建過濾器，實現javax.servlet.Filter接口 * 2、在過濾器的重寫方法doFilter中寫我們過濾操作：編碼、登錄攔截 * 3、配置web.xml中的過濾器 * <filter> <filter-name>myFilter</filter-name> <filter-class>com.blm.filter.MyFilter</filter-class> </filter> <filter-mapping> <filter-name>myFilter</filter-name>    <url-pattern>/guo/*</url-pattern> </filter-mapping> * @author Administrator * */web.xml配置：  <filter> <filter-name>myFilter</filter-name> <filter-class>com.blm.filter.MyFilter</filter-class> </filter> <filter-mapping> <filter-name>myFilter</filter-name>    <url-pattern>/guo/*</url-pattern> </filter-mapping>java代碼：package com.blm.filter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletContext;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class MyFilter implements Filter { static int number = 1; @Override public void destroy() { } @Override public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException { System.out.session中獲取 number = number+1; if (number> 5) { // 登錄成功 // 放行 arg2.doFilter(arg0, arg1); } else { //登錄失敗，返回登錄頁面 HttpServletResponse resp = (HttpServletResponse)arg1; resp.sendRedirect("/filterdemo/login.html"); } } @Override public void init(FilterConfig arg0) throws ServletException { }}上傳文件html代碼：<!-- 上傳文件時，必須要有：enctype="mult