request對象的增強 裝飾設計模式學習筆記二
阿新 • • 發佈：2018-04-19
request對象的增強 裝飾設計模式學
使用Decorator模式包裝request對象，完全解決get、post請求方式下的亂碼問題
Servlet API 中提供了一個request對象的Decorator設計模式的默認實現類HttpServletRequestWrapper ， （HttpServletRequestWrapper 類實現了request 接口中的所有方法，但這些方法的內部實現都是僅僅調用了一下所包裝的的 request 對象的對應方法）以避免用戶在對request對象進行增強時需要實現request接口中的所有方法
MyRequest
import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; /**對HttpServletRequest對象包裝/裝飾*/ public class MyRequest extends HttpServletRequestWrapper{ private HttpServletRequest request; public MyRequest(HttpServletRequest request) { super(request); this.request = request; } //重寫父類的方法 public String getParameter(String name) {//表單項的名字 String value = null; //取得客戶端的請求方式[GET/POST] String method = request.getMethod(); if("GET".equals(method)){ try { value = request.getParameter(name);//亂碼 byte[] buf = value.getBytes("ISO8859-1"); value = new String(buf,"UTF-8");//正碼 } catch (Exception e) { e.printStackTrace(); } }else if("POST".equals(method)){ try { request.setCharacterEncoding("UTF-8"); value = request.getParameter(name);//正碼 } catch (Exception e) { e.printStackTrace(); } } value = filter(value); return value; } //轉義方法 public String filter(String message) { if (message == null) return (null); char content[] = new char[message.length()]; message.getChars(0, message.length(), content, 0); StringBuffer result = new StringBuffer(content.length + 50); for (int i = 0; i < content.length; i++) { switch (content[i]) { case ‘<‘: result.append("<"); break; case ‘>‘: result.append(">"); break; case ‘&‘: result.append("&"); break; case ‘"‘: result.append("""); break; default: result.append(content[i]); } } return (result.toString()); }
GetPostServlet
import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class GetPostServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request,response); } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String username = request.getParameter("username"); response.getWriter().write(username); } }
longin
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>登陸頁面</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <form action="${pageContext.request.contextPath}/GetPostServlet" method="post"> <table border="1" align="center"> <caption>用戶登陸</caption> <tr> <th>用戶名</th> <td><input type="text" name="username"/> </td> <td colspan="5" align="center"> <input type="submit" value="提交"/> </td> </tr> </table> </form> </body> </html>
request對象的增強 裝飾設計模式學習筆記二