对mysql数据的连接操作和关闭

package database;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class MysqlTest {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {//加载驱动
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        try {//获取连接 jdbc:mysql:// 这一段是固定格式，localhost是服务器地址，3306是端口，服务器安装的时候配置的，root是用户名，写死的，密码是安装服务器的时候配置的。
             conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydata","root","");
        } catch (SQLException e) {
            e.printStackTrace();
        }
        try {//根据连接获取一个执行sql语句的对象
            stmt = conn.createStatement();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        try {//执行sql语句
            rs = stmt.executeQuery("select * from dept");
        } catch (SQLException e) {
            e.printStackTrace();
        }
        try {//打印表里的内容，下标从1开始
            while(rs.next()){
                System.out.print(rs.getString(1)+" ");
                System.out.print(rs.getString(2)+" ");
                System.out.print(rs.getString(3));
                System.out.println();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        try {//关闭连接
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}