Servlet跳转

来源：互联网发布：陕西广电网络官网编辑：程序博客网时间：2024/05/29 16:22

在Servlet内实现跳转

常见的Servlet内跳转有两种：
（1）重定向：对应JSP内置对象中的sendRedirect
respose.sendRedirect(“URL地址”);
（2）服务器内跳转：对应JSP中的forward标签
ServletContext application = this.getServletContext();
ServletContext application = this.getServletContext();
RequestDispatcher rd = application.getRequestDispatcher(“URL地址”);
rd.forward(request, response);

编写跳转Servlet

创建一个名为JumpServlet的Servlet
代码如下：

package cn.lystery.servlet;import java.io.IOException;import javax.servlet.RequestDispatcher;import javax.servlet.ServletContext;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class JumpServlet extends HttpServlet {    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        resp.setContentType("text/html;charset=utf-8");        String user = "Lystery";//模拟用户        req.setAttribute("user", user);        ServletContext application = this.getServletContext();        RequestDispatcher rd = application.getRequestDispatcher("/index.jsp");        rd.forward(req, resp);    }}

配置Servlet

配置代码如下：

<?xml version="1.0" encoding="UTF-8"?><web-app id="WebApp_9" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee                     http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">    <servlet>        <servlet-name>JumpServlet</servlet-name>        <servlet-class>cn.lystery.servlet.JumpServlet</servlet-class>    </servlet>    <servlet-mapping>        <servlet-name>JumpServlet</servlet-name>        <url-pattern>/JumpServlet</url-pattern>    </servlet-mapping></web-app>

编写index.jsp界面

index.jsp页面存在于WebContent目录下
这里写图片描述
编写index.jsp界面

<%@ page language="java" contentType="text/html; charset=utf-8"    pageEncoding="utf-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>欢迎界面</title></head><body>欢迎<br><%=request.getAttribute("user") %></body></html>

部署并测试JumpServlet

在地址栏输入http://localhost:8080/MyServlet/JumpServlet
这里写图片描述
发现已经跳转到index.jsp界面，显示出对应内容

使用重定向进行跳转

对JumpServlet进行如下更改

package cn.lystery.servlet;import java.io.IOException;import javax.servlet.RequestDispatcher;import javax.servlet.ServletContext;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class JumpServlet extends HttpServlet {    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        resp.setContentType("text/html;charset=utf-8");        String user = "Lystery";//模拟用户        req.setAttribute("user", user);        resp.sendRedirect("index.jsp");    }}

测试发现当运行是地址路径变成index.jsp但是传递的参数不见了这就是两者的区别
这里写图片描述

0 0