MVC是三个单词的缩写：M，Model（模型）；V,View( 视图 )，C，Control（控制）。
MVC模式的目的就是实现Web系统的职能分工Model层：实现系统的业务逻辑(javaBean)
View层：负责与用户交互，即在界面上展示数据对象给用户(html，jsp)Control层：Model与View之间沟通的桥梁，它可以分派用户的请求并选择恰当的视图以用于显示，同时它也可以解释用户的输入并将它们映射为模型层可执行的操作(Servlet)
下面通过一个登录的实例体现MVC：
项目结构如下：
其中，login.jsp为登录页面；succes.jsp为登陆成功页面；unsuccessful.jsp为登录失败页面
login.jsp：
<body>
<center>
<form action="UserServlet" method="post">
<h4>登录</h4>
<hr/>
姓名：<input type="text" name="username"/><br/>
密码：<input type="password" name="password"/><br/>
<input type="submit" value="提交"/>
</form>
</center>
</body>success.jsp：
<body>
<center>
<h3>登陆成功</h3>
<a href="<%=path %>/login.jsp">后退</a>
</center>
</body>unsuccessful.jsp：
<body>
<center>
<h3>登陆失败</h3>
<a href="<%=path %>/login.jsp">后退</a>
</center>
</body>
UserServlet.java(获取视图层传过来的参数，并传给模型层，待模型层判断后调转到相应的页面)
package com.mvc.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.mvc.javaBean.User;
public class UserServlet extends HttpServlet{
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
String userName = request.getParameter("username");
String password = request.getParameter("password");
User user = new User();
if(user.validatorUser(userName, password)){
response.sendRedirect("success.jsp");
}
else{
response.sendRedirect("unsuccessful.jsp");
}
}
}
User.java(实现业务逻辑，即验证用户名与密码是否正确，在这里仅仅是验证字符串是否相等，姓名与密码都为“admin”时，登陆成功，也可以加上数据库连接代码)
package com.mvc.javaBean;
public class User {
public boolean validatorUser(String username, String password){
if(username.equals("admin") && password.equals("admin")){
return true;
}
else{
return false;
}
}
}
下面是web.xml的配置
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>MVC</display-name>
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>UserServlet</servlet-name>
<servlet-class>com.mvc.servlet.UserServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UserServlet</servlet-name>
<url-pattern>/UserServlet</url-pattern>
</servlet-mapping>
</web-app>
在该实例中
Model层：User.java
View层：ogin.jsp；succes.jsp；unsuccessful.jspControl层：UserServlet.java
具体代码下载猛点下方
