url override and HttpSession implements session for form
阿新 • • 發佈：2018-12-02
url 重寫結合HttpSession實現會話管理之 form 提交
package com.test; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession;import java.io.IOException; import java.io.PrintWriter; @WebServlet("/questionnaire") public class Questionnaire extends HttpServlet { protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); out.println("<!DOCTYPE html>"); out.println("<html>"); out.println("<head>"); out.println("<meta charset='UTF-8'>"); out.println("<title>問卷調查</title>"); out.println("</head>"); out.println("<body>"); String page = request.getParameter("page"); if(page == null) { // 第一頁問卷 out.println("<form action='questionnaire' method='get'>"); out.println("問題一：<input type='text' name='p1q1'><br>"); out.println("問題二：<input type='text' name='p1q2'><br>"); out.println("<input type='submit' name='page' value='page2'>"); out.println("</form>"); } else if("page2".equals(page)) { // 第二頁問卷 /** * 下面這三行程式碼的順序不可變 */ HttpSession session = request.getSession(); String url = response.encodeURL("questionnaire"); out.println("<form action=\"" + url + "\" method=\"get\">"); session.setAttribute("p1q1", request.getParameter("p1q1")); session.setAttribute("p1q2", request.getParameter("p1q2")); out.println("問題三：<input type='text' name='p2q1'> <br>"); out.println("<input type='submit' name='page' value='finish'>"); out.println("</form>"); } else if("finish".equals(page)) { // 最後答案收集 HttpSession session = request.getSession(); out.println(session.getAttribute("p1q1") + "<br>"); out.println(session.getAttribute("p1q2") + "<br>"); out.println(request.getParameter("p2q1") + "<br>"); } out.println("</body>"); out.println("</html>"); out.close(); } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } }