2020-09-03

import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

/**
 * @author JessieWu
 * @create 2020-09-02  18:37
 */
public class ConnectionTest {
    //方式一：
    @Test
    public void testConnection1() throws SQLException {
        //获取Driver的实现类对象
        Driver driver = new com.mysql.cj.jdbc.Driver();
        String url = "jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8&serverTimezone=UTC";
        //用户名和密码
        Properties info = new Properties();
        info.setProperty("user","root");
        info.setProperty("password","3267754ww");
        Connection connect = driver.connect(url, info);
        System.out.println(connect);
    }

    //方式二：对方式一的一个迭代
    @Test
    public void testConnection2() throws Exception {
        //获取Driver的实现类对象，利用反射来实现
        Class clazz = Class.forName("com.mysql.cj.jdbc.Driver");
        Driver driver = (Driver) clazz.newInstance();

        String url = "jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8&serverTimezone=UTC";
        Properties info = new Properties();
        info.setProperty("user","root");
        info.setProperty("password","3267754ww");

        Connection connect = driver.connect(url, info);
        System.out.println(connect);
    }



    //方式三：使用DriverManager来代替
    @Test
    public void testConnection() throws Exception {
        //1.获取Driver实现类的对象
        Class clazz = Class.forName("com.mysql.cj.jdbc.Driver");
        Driver o = (Driver) clazz.newInstance();

        //2.提供另外三个链接的基本信息

        String url = "jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8&serverTimezone=UTC";
        String user = "root";
        String password = "3267754ww";
        //注册驱动
        DriverManager.registerDriver(o);

        //获取连接
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);
    }

    //方式四：使用DriverManager来代替的优化
    @Test
    public void newtestConnection() throws Exception {
        //1.提供另外三个链接的基本信息

        String url = "jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8&serverTimezone=UTC";
        String user = "root";
        String password = "3267754ww";
        //2.获取Driver实现类的对象,可以省略是因为有静态代码块，自动加载注册了
        Class.forName("com.mysql.cj.jdbc.Driver");
//        Driver o = (Driver) clazz.newInstance();
//        //注册驱动
//        DriverManager.registerDriver(o);

        //3.获取连接
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);
    }
    //方式五：最终版,将数据库链接需要的4个基本信息封装到配置文件
    @Test
    public void lastVersion() throws IOException, ClassNotFoundException, SQLException {
        //1.读取配置文件中的4个基本信息
        InputStream is = ConnectionTest.class.getClassLoader().getResourceAsStream("jdbc.properties");
        Properties props = new Properties();
        props.load(is);
        String user = props.getProperty("user");
        String password = props.getProperty("password");
        String url = props.getProperty("url");
        String driverClass = props.getProperty("driverClass");

        //2.加载驱动
        Class.forName(driverClass);

        //3.获取连接
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);
    }
}