jdbc的学习

如何通过java代码来连接数据库

今天我们来看看如何通过java代码连接mysql数据库，

有三种方式，先导入mysql的驱动程序包，

 package demo;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

import com.mysql.jdbc.Driver;
 
public class Sql1 {
	private static String url="jdbc:mysql://localhost:3306/shuying";
	private static String user="root";
	private static String password="root";
public static void main(String[] args) throws Exception {
	//t1();
//t3();
	t2();

}
//使用驱动管理类
private static void t2() throws SQLException {
	//注册一次驱动
	Driver driver=new com.mysql.jdbc.Driver();
	//注册驱动
	DriverManager.registerDriver(driver);
	////.使用驱动管理类获取连接
	Connection connection = DriverManager.getConnection(url, user, password);
	System.out.println(connection);
}
//改良版，只用注册一次
private static void t3() throws ClassNotFoundException, SQLException {
	//1、通过反射获取对象(只需注册一次)
	Class.forName("com.mysql.jdbc.Driver");
	//2.使用驱动管理类获取连接
		Connection connection = DriverManager.getConnection(url, user, password);
		System.out.println(connection);
}
//直接使用驱动程序连接
private static void t1() throws SQLException {
	//创建驱动实现类对象
	Driver driver=new com.mysql.jdbc.Driver();
   Properties properties=new Properties();
   properties.setProperty("user", user);
   properties.setProperty("password", password);
   //连接数据库
   Connection connect = driver.connect(url, properties);
   System.out.println(connect);
}
}