idea创建简单web项目分析Servlet的请求转发与重定向的区别

 注：如需转载，请附上原文链接，如有建议或意见，欢迎批评指正！

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

 import javax.servlet.ServletContext;

 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 java.io.IOException;

 @WebServlet("/ServletDemo1")

 public class ServletDemo1 extends HttpServlet {

     @Override

     public void init() throws ServletException {

         System.out.println("init()方法");

     }

     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

         System.out.println("doPost()方法");

         doGet(request, response);

     }

     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

         String a = request.getParameter("a");

         String b = request.getParameter("b");

         int sum = Integer.valueOf(a) + Integer.valueOf(b);

         request.setAttribute("sum", sum);

         // 方式一：PrintWriter对象写入

 //        response.getWriter().print(sum);

         // 方式二：请求转发

 //        request.getRequestDispatcher("sum.jsp").forward(request, response);

         // 方式三：重定向

         ServletContext sc = request.getServletContext();

         sc.setAttribute("sum2", sum);

         response.sendRedirect("sum2.jsp");

         System.out.println("doGet()方法");

     }

     @Override

     public void destroy() {

         System.out.println("destroy()方法");

     }

 }

// 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：

巴特西

idea创建简单web项目分析Servlet的请求转发与重定向的区别

最新文章

热门文章