Servlet简单应用

1.先在TOMCAT下建立一个测试的工程TestServlet,然后从别的工程拷贝过来一个WEB-INF，其中最少有web.xml和classes!
2.先修改一下web.xml,基本格式是:

1.先在TOMCAT下建立一个测试的工程TestServlet,然后从别的工程拷贝过来一个WEB-INF，其中最少有web.xml和classes!
2.先修改一下web.xml,基本格式是:


 
 
    columnservlet
    com.servlet.TestingServlet
 

    columnservlet
    /servlet/columnservlet

  true

3.在工程下写一个测试的jsp页面,名为TestJsp.jsp:
<%@ page contentType="text/html;charset=gb2312" %>
<%@ page import="java.util.*,java.lang.*"%>
<%
int num = 0;
Integer strTmp = (Integer)request.getAttribute("ReturnNum");
 if (strTmp!=null)
 {
  num=strTmp.intValue();
 }
%>


 
  
 
 
  

   
   
    
     
    
    
     
    
     
    
   

显示数字

<%=num%>

  

 

4.在eclipse下建立一个Servlet工程,导入servlet.jar包
建立com.servlet.TestingServlet,与web.xml里的servlet相对应

package com.servlet;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.*;

public class TestingServlet extends HttpServlet
{
 protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException
    {
        doPost(request, response);
    }
 protected void doPost(HttpServletRequest request,
   HttpServletResponse response) throws ServletException, IOException
 {
  doExcute(request, response);
 }
 private void doExcute(HttpServletRequest request,
      HttpServletResponse response)
 {
  RequestDispatcher rd = null;
        /* 获取上下文环境 */
        ServletContext sc = null;
        String strAction = null;
        strAction = request.getParameter("numC");
        int i=Integer.valueOf(strAction).intValue();
        i=i+1;
       
        String strSuccessPageURL = "/TestJsp.jsp";//这是查询主页面
        System.out.println("调用了业务逻辑查询 " + strAction);
       
        request.setAttribute("ReturnNum",new Integer(i));      
        try
        {
            /* 获取上下文环境 */
            sc = getServletContext();
            /* 设置返回地址 */
            rd = sc.getRequestDispatcher(strSuccessPageURL);
            /* forward到结果页面 */
            rd.forward(request, response);

        } catch (ServletException e)
        {
            e.printStackTrace();
        } catch (IOException e)
        {
            e.printStackTrace();
        }
       
 }
}

5.把eclipse中刚才建立的TestingServlet的class文件导入tomcat的TestServlet工程的WEB-INF下的classes下,
6.重启tomcat后,敲入就可以看到效果了!