今日作为：我发现昨天写的还是有问题，今天用土办法先完成了基本的代码，并且测试了一下能通过

                 然后准备用 JDBC Template的时候发现资料上全都是教你怎么用spring JDBC Template

                 晚上学了一点，明天用spring JDBC Template写完(要是快的话也把Mybatis也搞搞）

实体类：

package com.jnshu.demo.vo;

public class MyRealmp
{
    private int id;
    private String name;
    private String school;
    private String online_un;
    private int number;
    private String city;

    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 String getSchool() {
        return school;
    }

    public void setSchool(String school) {
        this.school = school;
    }

    public String getOnline_un() {
        return online_un;
    }

    public void setOnline_un(String online_un) {
        this.online_un = online_un;
    }

    public int getNumber() {
        return number;
    }

    public void setNumber(int number) {
        this.number = number;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }
}

实现类：

package com.jnshu.demo.impl;



import com.jnshu.demo.dao.IMYempDAO;
import com.jnshu.demo.util.DatabaseConnection;
import com.jnshu.demo.vo.MyRealmp;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class MyDAOImpl implements IMYempDAO{



    public MyDAOImpl() throws SQLException {
        String sql = "select * from students";
        Connection conn = DatabaseConnection.getConnection();
        PreparedStatement pstmt = conn.prepareStatement(sql);
        ResultSet set = pstmt.executeQuery();
        MyRealmp rs = new MyRealmp();
        while (set.next()){
            rs.setId(set.getInt("id"));
            rs.setName(set.getString("name"));
            rs.setSchool(set.getString("school"));
            rs.setOnline_un(set.getString("online_un"));
            rs.setNumber(set.getInt("number"));
            rs.setCity(set.getString("city"));
        }
        System.out.println("ID:"+rs.getId()+"  "+"Name:"+rs.getName()+"  "+"School:"+rs.getSchool()+"  "+"Online_un:"+rs.getOnline_un()+"  "+"Number:"+rs.getNumber()+"  "+"City:"+rs.getCity());
        DatabaseConnection.closeALL(conn,pstmt);
    }
}

连接数据库：

package com.jnshu.demo.util;

import java.sql.*;

public class DatabaseConnection {
    private static final String driver = "com.mysql.cj.jdbc.Driver";
    private static final String url = "jdbc:mysql://localhost:3306/it-xzy";
    private static final String user = "root";
    private static final String password = "54229103w";
    static{
        try{
            Class.forName(driver);
        }catch (ClassNotFoundException e){
            e.printStackTrace();
        }
    }
    public static Connection getConnection() throws SQLException{
        return DriverManager.getConnection(url,user,password);
    }

    public static void closeALL(Connection conn, PreparedStatement pstmt) throws SQLException{
        if(pstmt != null){
            pstmt.close();
        }
        if(conn != null){
            conn.close();
        }
    }
}

接口：

package com.jnshu.demo.dao;

public interface IMYempDAO
{
//当个标识接口先用着。。。。。。。。
}

运行结果：

明天计划：用spring Template完成1-17

今日问题：百度谷歌或者问边上的师兄了。。。。