package com.wang.dao;
 
import java.sql.*;
//用Java實(shí)現(xiàn)MySQL的增刪改查操作
public class Test1Demo {
    public static void main(String[]args){
        String url="jdbc:mysql://localhost:3306/ishop?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8";//mysql8的連接字符串，多了時區(qū)比之前的5
        String name="root";
        String password="root";
        String sql="SELECT *from tbl_commoditytype";
        //1.加載驅(qū)動
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");//在有錯誤提示的時候光標(biāo)移到錯誤處，alt+enter，
            try {
                //2.創(chuàng)建連接
                Connection  connection= DriverManager.getConnection(url,name,password);
                //3.創(chuàng)建命令窗口
                Statement statement = connection.createStatement();
                //4.執(zhí)行命令窗口里的語句
                ResultSet resultSet = statement.executeQuery(sql);
                //5.處理返回的結(jié)果集
                while (resultSet.next()){
                    //打印行的每一列
                  System.out.println(resultSet.getInt(1)+"\t"+resultSet.getString(2));
                }
                //6.關(guān)閉資源
                resultSet.close();
                statement.close();
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

package com.wang.demo;
 
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
 
public class Test01 {
 
    public static void main(String[] args) {//psvm回車可以直接敲出來哦
        //1.加載驅(qū)動
 
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
 
        } catch (ClassNotFoundException e) {
 
            e.printStackTrace();
 
        }
 
        //2.獲取鏈接,驅(qū)動管理器
        String url="jdbc:mysql://localhost:3306/ishop?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8";
        String user="root";
        String password="root";
 
        Connection connection = null;
        try {
            connection = DriverManager.getConnection(url, user, password);
 
        } catch (SQLException e) {
            e.printStackTrace();
        }
 
        //3.獲取命令
        Statement statement = null;
        try {
            statement = connection.createStatement();
 
        } catch (SQLException e) {
            e.printStackTrace();
        }
 
       // String sql="insert into tbl_commoditytype (id,name) values (6,'AA')"; //這個地方我后來發(fā)現(xiàn)我的數(shù)據(jù)庫表中id忘記設(shè)置自增長，就直接在這里直接寫上了id的值。之后增刪改操作依次執(zhí)行可查看表得三個結(jié)果圖
        //String sql="update tbl_commoditytype set name ='bb' where id=6";
 
        String sql="delete from tbl_commoditytype where id=6";
        int i = 0;
        //executeUpdate是做增刪改的
 
        //4.得到結(jié)果集并處理 
 
        try {
            i = statement.executeUpdate(sql);
 
        } catch (SQLException e) {
            e.printStackTrace();
        }
 
        System.out.println(i);//sout回車可快速創(chuàng)建System.out.println()哦
 
        //5.關(guān)閉資源
 
        //用到的connection（連接），statement（命令窗口），兩個接口，resultSet一個實(shí)現(xiàn)類（結(jié)果集）
 
        try {
            statement.close();
 
        } catch (SQLException e) {
            e.printStackTrace();
        }
 
        try {
            connection.close();
 
        } catch (SQLException e) {
 
            e.printStackTrace();
 
        }
    }
}

package com.wang.demo;
 
import java.sql.*;
 
/**
 * 斜杠雙星回車即可得這種注釋
 * 使用Statement進(jìn)行查詢操作
 */
public class Test02 {
    public static void main(String[] args) {
        //1.加載驅(qū)動
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        //2.獲取鏈接,驅(qū)動管理器
        String url="jdbc:mysql://localhost:3306/ishop?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8";
        String user="root";
        String password="root";
 
        Connection connection = null;
        try {
            connection = DriverManager.getConnection(url, user, password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        //3.獲取命令
        Statement statement = null;
        try {
            statement = connection.createStatement();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        // String sql="insert into tbl_commoditytype (id,name) values (6,'AA')";
        //String sql="update tbl_commoditytype set name ='bb' where id=6";
        //String sql="delete from tbl_commoditytype where id=6";
        String sql="select *from tbl_commoditytype";
        ResultSet resultSet=null;
        //executeUpdate是做增刪改的
        // 4.得到結(jié)果集并處理
        try {
            resultSet = statement.executeQuery(sql);
            //處理結(jié)果集，兩種方法，if（一條記錄）/while（不確定或者多條數(shù)據(jù)）
            while(resultSet.next()){
               String o= resultSet.getInt(1)+"\t"+resultSet.getString(2);
                //因?yàn)槲业谋淼谝涣惺莍nt,第二列是string。也可以把2換成name,也就是把索引（columnindex）換成列名（columnlabel}
                System.out.println(o);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        //sout回車可快速創(chuàng)建System.out.println()哦
 
        //5.關(guān)閉資源
        //用到的connection（連接），statement（命令窗口），兩個接口，resultSet一個實(shí)現(xiàn)類（結(jié)果集）
 
        try {
            statement.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        try {
            connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}