重定向与转发-白红宇

重定向与转发

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发布时间：2019-06-06

本文共 3779 字，大约阅读时间需要 12 分钟。

使用重定向方法sendRedirect()将用户重新定向到一个JSP页面或另一个Servlet。

RequestDispatcher对象调用void forward(ServletRequest request,ServletResponse response)

方法可以将用户对当前JSP页面或Servlet的请求转发给RequestDispatcher对象所指定的JSP页面或Servlet。

jsp文件如下：

1 <%@ page contentType="text/html;charset=GB2312" %>2 3 
      
       4      输入姓名:
       5  
       
输入年龄:
       6  
       
       7

两个Java文件如下：

1 package star.moon; 2 import java.io.*; 3 import javax.servlet.*; 4 import javax.servlet.http.*; 5 public class Verify extends HttpServlet 6 {  public void init(ServletConfig config) throws ServletException 7     {
   super.init(config); 8     } 9    public  void  doPost(HttpServletRequest request,HttpServletResponse response) 10                         throws ServletException,IOException11     {   String name=request.getParameter("name");      //获取客户提交的信息12         String age=request.getParameter("age");        //获取客户提交的信息13         if(name.length()==0||name==null)14          { response.sendRedirect("input.jsp");          //重定向15          }16         else if(age.length()==0||name==null)17          { response.sendRedirect("input.jsp");          //重定向18          }19         else if(age.length()>0)20          { try { int numberAge=Integer.parseInt(age);21                  if(numberAge<=0||numberAge>=150)22                   { response.sendRedirect("input.jsp");23                   }24                  else25                  {  RequestDispatcher dispatcher= 26                     request.getRequestDispatcher("forYouShowMessage");27                     dispatcher.forward(request, response);      //转发28                  }  29                }30             catch(NumberFormatException e)31               {  response.sendRedirect("input.jsp");32               }33          }34     } 35    public  void  doGet(HttpServletRequest request,HttpServletResponse response) 36                         throws ServletException,IOException37     {   doPost(request,response);38     }39 }

1 package star.moon; 2 import java.io.*; 3 import javax.servlet.*; 4 import javax.servlet.http.*; 5 public class ShowMessage extends HttpServlet 6 {  public void init(ServletConfig config) throws ServletException 7     {
   super.init(config); 8     } 9    public  void  doPost(HttpServletRequest request,HttpServletResponse response) 10                         throws ServletException,IOException11     {   response.setContentType("text/html;charset=GB2312");12         PrintWriter out=response.getWriter();13         String name=request.getParameter("name");      //获取客户提交的信息14         String age=request.getParameter("age");        //获取客户提交的信息15         try{ byte bb[]=name.getBytes("ISO-8859-1");16              name=new String(bb,"gb2312");17            }18         catch(Exception exp){}19         out.print("您的姓名是：");20         out.print(name);21         out.print("
您的年龄是：");22         out.print(age);23     } 24    public  void  doGet(HttpServletRequest request,HttpServletResponse response) 25                         throws ServletException,IOException26     {  doPost(request,response);27     }28 }

web.xml文件如下：

1 
      2 
     18 
     
      24 25   
      
       Welcome to Tomcat
      26   
      
       27      Welcome to Tomcat28   
      29   30   31 32 33 
      
       34         
       
        getSquare
       35         
       
        star.moon.Verify
       36 
      37 
      
       38         
       
        getSquare
       39         
       
        /verifyYourMessage
       40 
      41 42 43 
      
       44         
       
        getSquareOrCubic
       45         
       
        star.moon.ShowMessage
       46 
      47 
      
       48         
       
        getSquareOrCubic
       49         
       
        /forYouShowMessage
       50 
      51 52