一个简单的MVC模式练习

　　控制层Action接受从模型层DAO传来的数据，显现在视图层上。

package Action;

import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;

import DAO.StuDAO;
import Model.Student;
import Util.DBUtil;

public class StuAction {

    public static void main(String args[]) throws Exception {
            Connection conn = DBUtil.getConnection();
            Statement stmt = conn.createStatement();
//            ResultSet rs = stmt.executeQuery("select * from stuInfoTable");
    //
////            while(rs.next()) {
////                System.out.println(rs.getInt(1)+" "+ rs.getString(2)+" "+rs.getString(3));
////            }
            //不是直接 Student stu = null，这样试空指针
            Student stu = new Student();
            stu.setStuID(5);
            stu.setName("王五");
            stu.setSex("女");
            StuDAO sd = new StuDAO();
            //sd.addStu(stu);

//            stu.setName("马六");
//            stu.setSex("男");
//            sd.updateStu(stu);

            sd.delStu(stu.getStuID());

    }

    //直接调用StuDAO的方法来更新 增加 删除
    public void add(Student stu) throws Exception {
        StuDAO sd = new StuDAO();
        sd.addStu(stu);
    }
    //通过控制层来 链接视图层
}

package DAO;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import Model.Student;
import Util.DBUtil;

public class StuDAO {
    Connection conn = DBUtil.getConnection();
    //一个一个传参数很麻烦 直接传一个对象
    //如果stuID设置了自动递增  就不需要插入了
    public void  addStu(Student stu) throws Exception {
        String sql ="" + "insert into stuInfoTable" + "(" +
                " stuID,name,sex"+")" + "values(" + "?,?,?)";
        //这样的语句可以预加载在服务器里 execute后才会执行
        PreparedStatement ps = conn.prepareStatement(sql);
        ps.setInt(1, stu.getStuID());
        ps.setString(2, stu.getName());
        ps.setString(3, stu.getSex());
        ps.execute();
    }
    //和增加的逻辑一直  所以直接复制上述代码 然后修改sql语句
    //可以直接传过来stuID，但是这样需要根据ID去找Student
    public void updateStu(Student stu) throws Exception {
        //不加where语句的话 所有的都会更新

        //注意下面的语句   一定要有空格
        String sql ="" + "update stuInfoTable " + "set " +
                "name=?,sex=? " + "where "+ "stuID=?";
        //这样的语句可以预加载在服务器里 execute后才会执行
        PreparedStatement ps = conn.prepareStatement(sql);
        //打印出来sql语句 发现 中间少了 空格 然后修改上面的sql语句
        System.out.println(sql);
        //注意下面的 序号 要和update的序号一致
        ps.setString(1, stu.getName());
        ps.setString(2, stu.getSex());
        ps.setInt(3, stu.getStuID());
        ps.execute();
    }
    public void delStu(int stuID) throws Exception {

        String sql ="" + "delete stuInfoTable " +"where "+ "stuID=?";
        PreparedStatement ps = conn.prepareStatement(sql);
        ps.setInt(1, stuID);
        ps.execute();
    }
    //查询学生集合
    public List<Student> queryStu() throws Exception {
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery("select * from stuInfoTable");

        List<Student> stuList = new ArrayList<Student>();
        Student stu = null;
        while(rs.next()) {
            stu = new Student();
            stu.setStuID(rs.getInt(1));
            stu.setName(rs.getString(2));
            stu.setSex(rs.getString(3));
            stuList.add(stu);
        }
        return stuList;
    }
    //查询一个学生
    //应该需要和上面重载的 但是为了做实验 先写完所有方法 再去实现
    public Student queryOneStu() {
        return null;
    }

}

package Model;

public class Student {
    int stuID;
    String name;
    String sex;
    public int getStuID() {
        return stuID;
    }
    public void setStuID(int stuID) {
        this.stuID = stuID;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }

}

package Util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import DAO.StuDAO;
import Model.Student;

public class DBUtil {

    private static Connection conn;

    static {
        String url = "jdbc:sqlserver://localhost:1433;databasename=stuDB";

        try {
            // 1.注册驱动            // Class.forName("com.mysql.jdbc.Driver");
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            // 2.获得数据链接
            conn = DriverManager.getConnection(url, "sa", "123456");

        } catch (ClassNotFoundException | SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public static Connection getConnection() {
        return conn;
    }
}