JDBC程序编写步骤

1.注册驱动(加载Driver类)

2.获取连接(得到Connection)

3.执行增删改查(发送SQL给mysql执行)

4.释放资源(关闭相关连接)

数据库连接的5种方式

方式一：

package chapter01;
​
//第一个JDBC程序，完成简单的操作
//连接数据库方式一
import com.mysql.jdbc.Driver;
​
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
​
public class JDBC01 {
    public static void main(String[] args) throws SQLException {
​
        //1.注册驱动
        //Driver driver = new Driver();
        com.mysql.jdbc.Driver driver = new com.mysql.jdbc.Driver();
​
        //2.得到连接
        /*
        *1.jdbc:mysql(规定好表示协议，通过jdbc的方式连接mysql)
        *2.localhost(主机，可以是ip地址)
        *3.3306(表示mysql监听的端口)
        *4.myhan(连接到mysql的哪一个数据库)
        *5.mysql的连接本质就是java中socket连接
        * */
​
        String url = "jdbc:mysql://localhost:3306/myhan?        &useSSL=false&serverTimezone=UTC";
​
        //
        //将用户名和密码放入到Properties对象(user和password是规定好的)
        Properties properties = new Properties();
        properties.setProperty("user","root");//用户
        properties.setProperty("password","abc123");//密码
        //网络连接
        Connection connect = driver.connect(url, properties);
​
        //3.执行sql语句
        String sql = "insert into jh_db02 values(null,'tom','2011-12-15','12345','男')";
        //Statement用于执行静态SQL语句并返回其生成的结果对象
        Statement statement = connect.createStatement();
        int rows = statement.executeUpdate(sql);//若是dml语句，则返回的是影响行数
​
        System.out.println(rows > 0 ? "成功" : "失败");
​
        //4.关闭连接
        statement.close();
        connect.close();
​
​
​
​
    }
}

方式二：

package chapter01;
​
import java.sql.Connection;
import java.sql.Driver;
import java.sql.SQLException;
import java.util.Properties;
​
//连接数据库方式二
​
public class JDBC02 {
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, SQLException {
​
        //使用反射加载Driver类，动态加载，更加的灵活，减少依赖性
​
        //注册驱动
        String path = "com.mysql.cj.jdbc.Driver";
        Class class01 = Class.forName(path);
        Driver driver = (Driver)class01.newInstance();
​
        //得到连接
        String url = "jdbc:mysql://localhost:3306/myhan?&useSSL=false&serverTimezone=UTC";
        Properties properties = new Properties();
        properties.setProperty("user","root");
        properties.setProperty("password","abc123");
​
        Connection connect = driver.connect(url, properties);
        System.out.println(connect);
​
        //执行sql语句
​
​
        //关闭连接
        connect.close();
​
​
    }
}

方式三：

package chapter01;
​

//连接数据库方式三
​
import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
​
public class JDBC03 {
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, SQLException {
​
        //使用DriverManager 替代 Driver进行统一管理
        String path = "com.mysql.cj.jdbc.Driver";
        Class aClass = Class.forName(path);
        Driver driver = (Driver) aClass.newInstance();
​
        String url = "jdbc:mysql://localhost:3306/myhan?&useSSL=false&serverTimezone=UTC";
        String uesr = "root";
        String password = "abc123";
​
        DriverManager.deregisterDriver(driver);//注册驱动
        Connection connection = DriverManager.getConnection(url, uesr, password);
​
        System.out.println(connection);
​
​
    }
}

方式四：

package chapter01;

//该方式使用最多，有静态代码块已经自动完成注册驱动
​
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
​
public class JDBC04 {
    public static void main(String[] args) throws ClassNotFoundException, SQLException, SQLException {
​
        //使用Class.forName自动完成注册驱动
        String path = "com.mysql.jdbc.Driver";
        Class class01 = Class.forName(path);
        String url = "jdbc:mysql://localhost:3306/myhan";
        String user = "root";
        String password = "abc123";
​
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);
​
​
    }
}

方式五：

配置文件：

user=root
password=abc123
url=jdbc:mysql://localhost:3306/myhan
driver=com.mysql.jdbc.Driver

代码文件：

​
package chapter01;
​
//在方式四的基础上，增加配置文件，使得mysql更加灵活
​
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
​
public class JDBC05 {
    public static void main(String[] args) throws IOException, ClassNotFoundException, SQLException {
​
        //通过properites对象获取配置文件信息
        Properties properties = new Properties();
        properties.load(new FileInputStream("src\\mysql.properties"));
        //获取相关的值
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String driver = properties.getProperty("driver");
        String url = properties.getProperty("url");
​
        Class.forName(driver);
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);
​
    }
}