java-jdbc快速入门

简介

• JDBC就是使用Java语言操作关系数据库的一套API
• Java DataBase Connectivity

快速入门

-- mysql 中准备工作
create database if not exists my_db;
use my_db;
create table account(
    id int,
    name varchar(20),
    money int
);
insert into account values (1,'张三',1000),
                           (2,'李四',1000);
select  *from account;

代码总览：

  //1.注册驱动
        Class.forName("com.mysql.jdbc.Driver");
        //2.获取连接
        String url = "jdbc:mysql://localhost:3306/my_db";
        String name = "root";
        String password = "******"; // 填自己的密码哦
        Connection conn= DriverManager.getConnection(url,name,password);
        //sql语句
        String sql = "update account set money = 2000 where id=2;";
        //获取执行sql对象
        Statement stmt = conn.createStatement();

        int count = stmt.executeUpdate(sql);

        System.out.println(count);

        stmt.close();
        conn.close();

0. 创建工程导入jar包
把MySQL的jar包放到项目里面，然后右键这个jar包，添加到库，选模块库

1. 注册驱动

 //1.注册驱动
 Class.forName("com.mysql.jdbc.Driver");

mysql 5 往后的版本不写这一行代码也可以

Driver类下有这一段代码，会自动加载驱动类

    static {
        try {
            DriverManager.registerDriver(new Driver());
        } catch (SQLException var1) {
            throw new RuntimeException("Can't register driver!");
        }
    }

2. 获取连接

  //2.获取连接
  String url = "jdbc:mysql://localhost:3306/my_db"; 
  String name = "root";
  String password = "******";
  Connection conn= DriverManager.getConnection(url,name,password);

3. 定义sql语句

//sql语句
String sql = "update account set money = 2000 where id=2;";

4. 获取sql执行对象

Statement stmt = conn.createStatement();

5. 执行sql

int count = stmt.executeUpdate(sql);

6. 处理返回结果

System.out.println(count);

7. 释放资源

stmt.close();
conn.close();