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需求说明：
// index.jsp页面 1 <% 2 ??String basePath = request.getScheme()+":"+"//"+request.getServerName()+":"+request.getServerPort()+"/" 3 ??????????+request.getServletContext().getContextPath()+"/"; 4 %> 5 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 6 <html> 7 ??<head> 8 ????<title>ServletDemo加法运算</title> 9 ??</head>10 ??<body>11 ????<%--action: 表示访问的servlet路径--%>12 ????<%out.print("basePath意味着：" + basePath);%>13 ????<form action="<%=basePath%>ServletDemo1" method="post">14 ??????a: <input type="text" name="a"><br>15 ??????b: <input type="text" name="b"><br>16 ??????<input type="submit" value="计算"/><br>17 ????</form>18 ??</body>19 </html>// ServletDemo1.java
1 import javax.servlet.ServletContext; 2 import javax.servlet.ServletException; 3 import javax.servlet.annotation.WebServlet; 4 import javax.servlet.http.HttpServlet; 5 import javax.servlet.http.HttpServletRequest; 6 import javax.servlet.http.HttpServletResponse; 7 import java.io.IOException; 8 ?9 @WebServlet("/ServletDemo1")10 public class ServletDemo1 extends HttpServlet {11 ????@Override12 ????public void init() throws ServletException {13 ????????System.out.println("init()方法");14 ????}15 16 ????protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {17 ????????System.out.println("doPost()方法");18 ????????doGet(request, response);19 ????}20 21 ????protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {22 ????????String a = request.getParameter("a");23 ????????String b = request.getParameter("b");24 ????????int sum = Integer.valueOf(a) + Integer.valueOf(b);25 ????????request.setAttribute("sum", sum);26 ????????// 方式一：PrintWriter对象写入27 // ???????response.getWriter().print(sum);28 ????????// 方式二：请求转发29 // ???????request.getRequestDispatcher("sum.jsp").forward(request, response);30 ????????// 方式三：重定向31 ????????ServletContext sc = request.getServletContext();32 ????????sc.setAttribute("sum2", sum);33 ????????response.sendRedirect("sum2.jsp");34 ????????System.out.println("doGet()方法");35 ????}36 37 ????@Override38 ????public void destroy() {39 ????????System.out.println("destroy()方法");40 ????}41 }
// sum.jsp页面<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
???<title>请求跳转求和</title>
</head>
<body>
a + b = <%=request.getAttribute("sum")%>
</body>
</html>
// sum2.jsp页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
???<title>重定向跳转求和</title>
</head>
<body>
a + b = <%=application.getAttribute("sum2")%>
</body>
</html>
index.jsp页面效果图展示：
1. 方式一：PrintWriter对象写入效果图：
2. 方式二：请求转发效果图：
3. 重定向效果图：
idea创建简单web项目分析Servlet的请求转发与重定向的区别
原文地址：https://www.cnblogs.com/chris0710/p/8970543.html