model2

model2是由JSP+Servlet+JavaBean一起实现的，由jsp负责页面，JavaBean用于存储数据，Servlet处在jsp和JavaBean中间，负责调用JavaBean的存储方法将JSP传来的数据存储到数据库中。
这里要说以下MVC原理。
1. M model模型层，这是应用程序的核心部分，主要由JavaBean充当。可以是一个实体对象或者一种业务逻辑。
2. V view视图层提供与用户交互的界面，但是不包含任何的业务逻辑，只是将数据传递给Controller
3. C Controller控制层三层中的大佬，获取视图层的数据并且把他交由模型层处理。

简单实现例子

数据库

 create table tb_goods
    -> (name varchar(45),
    -> price double,
    -> description varchar(100)
    -> );

贴心提醒文件的位置

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <servlet>
        <servlet-name>GoodsServlet</servlet-name>
        <servlet-class>GoodsServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>GoodsServlet</servlet-name>
        <url-pattern>/GoodsServlet</url-pattern>
    </servlet-mapping>
</web-app>

视图层（index.jsp）

<%--
  Created by IntelliJ IDEA.
  User: 11955
  Date: 2018/10/20
  Time: 9:33
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
  <form action="GoodsServlet" method="post" onsubmit="return save(this);">
    <table border="1" align="center" width="300">

      <tr>
        <td align="right">商品名称</td>
        <td> <input type="text" name="name"> </td>
      </tr>

      <tr>
        <td align="right">价格</td>
        <td> <input type="text" name="price"> </td>
      </tr>

      <tr>
        <td align="right">商品描述</td>
        <td> <textarea name="description" cols="30" rows="3"></textarea> </td>
      </tr>

      <tr>
        <td align="center" colspan="2">
          <input type="submit" value="ok">
          <input type="reset" value="reset">
        </td>
      </tr>

    </table>
  </form>
  </body>
</html>

控制层，也就是servlet

import com.model.Goods;
import com.model.GoodsDao;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

@WebServlet(name = "GoodsServlet")
public class GoodsServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html");
        response.setCharacterEncoding("utf-8");
        request.setCharacterEncoding("utf-8");
        PrintWriter out = response.getWriter();
        String name = request.getParameter("name");
        String price = request.getParameter("price");
        String description = request.getParameter("description");
        Goods goods = new Goods();
        goods.setName(name);
        goods.setPrice(Double.valueOf(price));
        goods.setDescription(description);
        GoodsDao goodsDao = new GoodsDao();
        goodsDao.saveGoods(goods);
        out.print("ok");
        out.flush();
        out.close();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }
}

模型层，两个JavaBean

/**
 * Demo Goods
 *
 * @author linMinRui
 * @date 2016/10/20
 */
package com.model;

public class Goods {
    private String name;
    private double price;
    private String description;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double proice) {
        this.price = proice;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
}

/**
 * Demo Goods
 *
 * @author GoodsDao
 * @date 2016/10/20
 */
package com.model;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;

public class GoodsDao {
    public void saveGoods(Goods goods){
        try{
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/test";
            Connection conn = DriverManager.getConnection(url, "root", "123456");
            String sql = "insert into tb_goods(name, price, description) values(?,?,?)";
            PreparedStatement ps = conn.prepareStatement(sql);
            ps.setString(1,goods.getName());
            ps.setDouble(2,goods.getPrice());
            ps.setString(3,goods.getDescription());
            ps.executeUpdate();
            ps.close();
            conn.close();
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

运行index.jsp输入数据，就可以在数据库中查看到。

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