简单的JDBC操作mysql数据库的demo

java操作数据库步骤：

1.注册并加载驱动

​ DriverManager.registerDriver(Driver driver);

​ 或者Class.forName("driverName");
注意：在开发中，通常使用Class.forName("com.mysql.jdbc.Driver");注册驱动，不用DriverManager.registerDriver(driver);因为这个方法注册了两次驱动。

2.获取Connection连接对象

​ Connection con = DriverManager.getConnection(url,username,password);

3.获取操作数据库的对象Statement(或者PreparedStatement)

​ Statement stmt = con.createStatement();

4.向数据库发送sql语句，执行操作。

​ 比如：String sql = "select * from users";调用executeQuery(sql)

5.执行查询操作，返回ResultSet结果集对象，结果集里面封装的是查询的结果。

​ 遍历ResultSet,获取我们查询的数据

6.关闭连接，释放资源（倒关原则，先出现的，后关闭）

Demo：

1.创建数据库：：jdbc,在这个数据库里创建表，插入几条数据

create datebase ydd01;

use ydd01;

CREATE TABLE users (
id INT PRIMARY KEY auto_increment,
name VARCHAR ( 32 ),
password VARCHAR ( 32 ),
email VARCHAR ( 160 ),
birthday Date 
);

insert into users(name,password,email,birthday) values('hh','123','hh@qq.com','1990-09-09');
insert into users(name,password,email,birthday) values('ydd','123','ydd@qq.com','1991-09-09');
insert into users(name,password,email,birthday) values('lyy','123','lyy@qq.com','1992-09-09');
insert into users(name,password,email,birthday) values('ljj','123','ljj@qq.com','1993-09-09');

2.操作代码

package cn.itcast.jdbc.example;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.management.RuntimeErrorException;
import java.sql.Date;
import com.mysql.jdbc.Driver;

public class Example01 {
	// 执行查询操作
	public static void main(String[] args) {
		Connection con = null;
		Statement stmt = null;
		ResultSet rs = null;
		try {
			// 1.注册并加载驱动
			Driver driver = new Driver();
			//DriverManager.registerDriver(driver);
			Class.forName("com.mysql.jdbc.Driver");
			// 2.获取连接对象
			String url = "jdbc:mysql://localhost:3306/ydd01";
			String user = "root";
			String password = "123456";
			con = DriverManager.getConnection(url, user, password);
			// 3.获取操作数据的对象
			stmt = con.createStatement();
			// 4.向数据库发送查询语句
			String sql01 = "select * from users";
			rs = stmt.executeQuery(sql01);
			// 5.获取查询的数据
			while (rs.next()) {
				int id = rs.getInt("id");
				String name = rs.getString("name");
				String password01 = rs.getString("password");
				String email = rs.getString("email");
				Date birthday = rs.getDate("birthday");
				System.out.println(id + " " + name + " " + password01 + " " + email + " " + birthday);
			}
		} catch (Exception e) {
			throw new RuntimeException(e);
		} finally {
			
			// 6.关闭连接，释放资源
			if (rs != null) {
				try {
					rs.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (rs != null) {
				try {
					stmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (con != null) {
				try {
					con.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			System.out.println("关闭资源代码已执行");
		}
	}
}