采用MVC模式JDBC演示案例

MVC三层架构：

Model 模型层，数据处理和业务逻辑

View 视图层，为客户展示内容

Control 控制层，协调控制，更新模型

案例如下：

1、获得数据库连接

package com.db;

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

public class JDBCUtil {
    
    private static final String URL="jdbc:mysql://127.0.0.1:3306/student";
    private static final String USER="root";
    private static final String PASSWORD="root";
    private static Connection conn = null;
    
    static{
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(URL, USER, PASSWORD);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    
    public static Connection getConn(){
        return conn;
    }

}

2、创建模型

package com.model;

public class Student {

    private int id;
    private String name;
    private char sex;
    private int age;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public char getSex() {
        return sex;
    }
    public void setSex(char sex) {
        this.sex = sex;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    
    
    
}

3、创建数据库访问对象--DAO

package com.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 com.zhidi.db.JDBCUtil;
import com.zhidi.model.Student;

public class StuUtile {
    
    private static final Connection conn = JDBCUtil.getConn();
    
    //添加
    public void addStu(Student stu) throws SQLException{
        String sql = "insert into stu"+
                    "(id,name,sex,age) values (?,?,?,?)";
        PreparedStatement ps = conn.prepareStatement(sql);
        ps.setInt(1, stu.getId());
        ps.setString(2, stu.getName());
        ps.setString(3,String.valueOf(stu.getSex()));
        ps.setInt(4, stu.getAge());
        
        ps.execute();
        
    }
    
    //删除
    public void delStu(int id) throws SQLException{
        String sql = "delete from stu where id=?";
    PreparedStatement ps = conn.prepareStatement(sql);
    ps.setInt(1,id);
    
    ps.execute();
    }
    
    //修改
    public void updateStu(Student stu) throws SQLException{
        String sql = "update stu set name=?,sex=?,age=? where "+
                "id=?";
    PreparedStatement ps = conn.prepareStatement(sql);
    ps.setString(1, stu.getName());
    ps.setString(2,String.valueOf(stu.getSex()));
    ps.setInt(3, stu.getAge());
    ps.setInt(4, stu.getId());
    
    ps.execute();
    }
    
    //查询所有学生
    public List<Student> query() {
        List<Student> list = new ArrayList<Student>();
        try {
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("select * from stu");
            
            Student stu = null;
            while(rs.next()){
                stu = new Student();
                stu.setId(rs.getInt("id"));
                stu.setName(rs.getString("name"));
                String sex = rs.getString("sex");
                char[] ch = sex.toCharArray();
                for (char c : ch) {
                    stu.setSex(c);
                }
                stu.setAge(rs.getInt("age"));
                list.add(stu);
            }
            
        } catch (SQLException e) {
            e.printStackTrace();
        }
        
        return list;
    }
    
    //查询单个学生
    public Student getStu(int id) throws SQLException{
        String sql = "select * from stu where id=?";
    PreparedStatement ps = conn.prepareStatement(sql);
    ps.setInt(1, id);
    
    ResultSet rs = ps.executeQuery();
    Student stu = null;
    while(rs.next()){
        stu = new Student();
        stu.setId(rs.getInt("id"));
        stu.setName(rs.getString("name"));
        String sex = rs.getString("sex");
        char[] ch = sex.toCharArray();
        for (char c : ch) {
            stu.setSex(c);
        }
        stu.setAge(rs.getInt("age"));
    }
        return stu;
    }

}

4、控制层逻辑代码

package com.control;

import java.sql.SQLException;
import java.util.List;

import com.zhidi.dao.StuUtile;
import com.zhidi.model.Student;

public class StuControl {

    public static void main(String[] args) throws SQLException {
        StuUtile su = new StuUtile();
        Student stu = new Student();
        stu.setId(10);
        stu.setName("张芳");
        stu.setSex('女');
        stu.setAge(20);
//        su.addStu(stu);
        
//        su.updateStu(stu);
        
//        su.delStu(10);
        Student s = su.getStu(1);
        System.out.println(s.getId()+" "+s.getName()+" "+s.getSex()+" "+s.getAge());
        
//        List<Student> list = su.query();
//        for (Student s : list) {
//            System.out.println(s.getId()+" "+s.getName()+" "+s.getSex()+" "+s.getAge());
//        }

    }

}