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Java用jdbc连接实现对MySQL增删改查操作

天使魔鬼 2022-04-14 阅读 67

目录

前言

1.新建项目

2.添加jar包

3.jdbc的连接

4、简单的MySQL增删改查操作


前言


1.新建项目

2.添加jar包

3.jdbc的连接

package com.wang.dao;

import java.sql.*;
//用Java实现MySQL的增删改查操作
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的连接字符串,多了时区比之前的5
        String name="root";
        String password="root";
        String sql="SELECT *from tbl_commoditytype";
        //1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");//在有错误提示的时候光标移到错误处,alt+enter,
            try {
                //2.创建连接
                Connection  connection= DriverManager.getConnection(url,name,password);
                //3.创建命令窗口
                Statement statement = connection.createStatement();
                //4.执行命令窗口里的语句
                ResultSet resultSet = statement.executeQuery(sql);
                //5.处理返回的结果集
                while (resultSet.next()){
                    //打印行的每一列
                  System.out.println(resultSet.getInt(1)+"\t"+resultSet.getString(2));
                }
                //6.关闭资源
                resultSet.close();
                statement.close();
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

4、简单的MySQL增删改查操作

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回车可以直接敲出来哦

        //1.加载驱动

        try {

            Class.forName("com.mysql.cj.jdbc.Driver");

        } catch (ClassNotFoundException e) {

            e.printStackTrace();

        }

        //2.获取链接,驱动管理器

        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.获取命令

        Statement statement = null;

        try {

            statement = connection.createStatement();

        } catch (SQLException e) {

            e.printStackTrace();

        }

       // String sql="insert into tbl_commoditytype (id,name) values (6,'AA')"; //这个地方我后来发现我的数据库表中id忘记设置自增长,就直接在这里直接写上了id的值。之后增删改操作依次执行可查看表得三个结果图

        //String sql="update tbl_commoditytype set name ='bb' where id=6";

        String sql="delete from tbl_commoditytype where id=6";

        int i = 0;

        //executeUpdate是做增删改的

        //4.得到结果集并处理 

        try {

            i = statement.executeUpdate(sql);

        } catch (SQLException e) {

            e.printStackTrace();

        }

        System.out.println(i);//sout回车可快速创建System.out.println()哦

       

        //5.关闭资源

        //用到的connection(连接),statement(命令窗口),两个接口,resultSet一个实现类(结果集)



        try {

            statement.close();

        } catch (SQLException e) {

            e.printStackTrace();

        }

        try {

            connection.close();

        } catch (SQLException e) {

            e.printStackTrace();

        }

    }



}

 

package com.wang.demo;

import java.sql.*;

/**
 * 斜杠双星回车即可得这种注释
 * 使用Statement进行查询操作
 */
public class Test02 {
    public static void main(String[] args) {
        //1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        //2.获取链接,驱动管理器
        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.获取命令
        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是做增删改的
        // 4.得到结果集并处理
        try {
            resultSet = statement.executeQuery(sql);
            //处理结果集,两种方法,if(一条记录)/while(不确定或者多条数据)
            while(resultSet.next()){
               String o= resultSet.getInt(1)+"\t"+resultSet.getString(2);
                //因为我的表第一列是int,第二列是string。也可以把2换成name,也就是把索引(columnindex)换成列名(columnlabel}
                System.out.println(o);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        //sout回车可快速创建System.out.println()哦

        //5.关闭资源
        //用到的connection(连接),statement(命令窗口),两个接口,resultSet一个实现类(结果集)

        try {
            statement.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        try {
            connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

 

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