response对象的转发和重定向

科技2022-07-21 95

1.forward的转发方式是直接转发的，而rediect则为间接转发

Forward：客户端和浏览器只发出一次请求, Servlet、 HTML、JSP或其它信息资源,由第二个信息资源响应该请求,在请求对象request中,保存的对象对于每个信息资源是共享的。 Redirect ：实际是两次请求,服务器端在响应第一次请求的时候 ,让浏览器再向另外一个URL发出请求,从而达到转发的目的。

2.重定向

指客户端向服务器a发送一个请求，而服务器Servlet1经过处理返回一个新的重新定向的指令，告诉客户端你现在需要访问另一个服务器b。

3.登录界面

<%@ 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> <base href="<%=basePath%>"> <title>My JSP 'login.jsp' starting page</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"> </head> <body> <form action="loginServlet.jsp" method="post"> 用户名 <input type="text" name="userName" /> </br> 密码 <input type="text" name="pwd" /> </br> <input type="submit" value="登录" /> </form> </body> </html>

处理登录

<%@ 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> <base href="<%=basePath%>"> <title>My JSP 'loginServlet.jsp' starting page</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"> </head> <body> <% String pwd = request.getParameter("pwd"); String userName = request.getParameter("userName"); if ("wj".equals(userName) && "123".equals(pwd)) { response.sendRedirect("success.jsp"); } %> </body> </html>

登录成功

4.转发

登录界面

<%@ 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> <base href="<%=basePath%>"> <title>My JSP 'login.jsp' starting page</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"> </head> <body> <% String message = ""; message = (String) request.getAttribute("message"); if (message == null) message = ""; %> <form action="loginServlet.jsp" method="post"> 用户名 <input type="text" name="userName" /> </br> 密码 <input type="text" name="pwd" /> <span style="color: red"><%=message%></span> </br> <input type="submit" value="登录" /> </form> </body> </html>

loginServlet服务代码

<%@ 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> <base href="<%=basePath%>"> <title>My JSP 'loginServlet.jsp' starting page</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"> </head> <body> <% String pwd = request.getParameter("pwd"); String userName = request.getParameter("userName"); //我们设定用户名为：zhangsan,密码为：123 if ("wj".equals(userName) && "123".equals(pwd)) { response.sendRedirect("success.jsp"); } else { request.setAttribute("message", "密码错误!"); //调用getRequestDispacther()方法，把请求转发给login.jsp request.getRequestDispatcher("login.jsp").forward(request, response); } %> </body> </html>

Processed: 0.010, SQL: 8