mvc例子

[原创]过去不会用mvc，经过摸索终于明白了，自己写了个例子，献给那些迷茫的java爱好者！！

注:过去不会用mvc，经过摸索终于明白了，自己写了个例子，献给那些迷茫的java爱好者！！
前提：
我用的sql2k,database:clear,table:testbean(newid(int),name(char),addr(char))
容器用的tomcat
//
test.jsp:
<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.sql.*" %>
<body>
<center>
<%=(String)request.getAttribute("alert")!=null?(String)request.getAttribute("alert"):""
    %>
<p>
<p>
<form name=f method="post" action="/servlet/FirstBean?req=no">
   号码:<input type=text name=deleteno size=4>
   <br>
   <input type=submit>
</form>
</center>
<body>

//bean:CheckNo
package bean;
import java.sql.*;
public class CheckNo
{
  private int no;
  int val;
  //
  public void setNo(int no){
      this.no=no;
  }
  //
  public int getNo(){
      return no;
  }
  //
  public int execdelete() throws ClassNotFoundException,SQLException{
      String con="delete from beantest where newid="+no;
      Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
      String url2="jdbc:microsoft:sqlserver://192.168.0.3:1433;DataBaseName=clear";
      String user="sa";
      String password="pft";
      Connection conn= DriverManager.getConnection(url2,user,password);
      Statement st=conn.createStatement();
      val=st.executeUpdate(con);
      st.close();
      conn.close();
      return val;
  }
}

//servlet:FirstBean
  import javax.servlet.*;
  import javax.servlet.http.*;
  import java.sql.*;
  import java.io.*;
  import bean.*;
  public class FirstBean extends HttpServlet {
     //定义全局变量
     int theno;
     //init
     public void init() throws ServletException {
         super.init();
     }
     //doget
     public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String req = request.getParameter("req");
        if(req==null){redirect(request,response,"test.jsp");}
     }
     //dopost
     public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        try{
         String req = request.getParameter("req");
        if(req==null){redirect(request,response,"test.jsp");}
        else if(req.equals("no")){
          theno=Integer.parseInt(request.getParameter("deleteno"));
          begin(request,response);
        }
        }catch(Exception e){
            System.out.print(e.toString());
        }
     }
     //begin
     public void begin(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
       try{
       CheckNo cn=new CheckNo();
       cn.setNo(theno);
       int val=cn.execdelete();
       if(val==1){
           //System.out.print("successful!");
           request.setAttribute("alert","删除成功");
           redirect(request,response,"test.jsp");
       }
       else{
           //System.out.print("Failed!");
           request.setAttribute("alert","删除失败");
           redirect(request,response,"test.jsp");
       }
       }catch(Exception e){
        System.out.print(e.toString());
       }
     }
     //redirect
     public void redirect(HttpServletRequest request, HttpServletResponse response, String directory) throws ServletException, IOException {
        RequestDispatcher redirectory = getServletContext().getRequestDispatcher("/mail/" + directory);
        redirectory.forward(request,response);
        }
  }

//目录结构
root
    mail
       test.jsp
    web-inf
       classes
          bean
             FirstBean.class