MVC模式學習

2019-11-18 14:49:35

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　　注:過去不會用mvc，經過摸索終于明白了，自己寫了個例子，獻給那些迷茫的java愛好者??！
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">
號碼:<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 {
//定義全局變量
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","刪除成功");
redirect(request,response,"test.jsp");
}
else{
//System.out.print("Failed!");
request.setAttribute("alert","刪除失敗");
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);
}
}

//目錄結構
root
mail
test.jsp
web-inf
classes
bean
FirstBean.class

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