java中connection问题

public class MainApp {
	public static void main(String[] args) {
		
		Connection conn = DBUtil1.getConnection();
		
		try {
			conn.close(); //这个conn关闭的话,工具类里面的conneection也会关闭
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		try {
			System.out.println(conn.isClosed());
		} catch (SQLException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}
		
		try {
			System.out.println(DBUtil1.connection.isClosed());
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

　　

package com.woniuxy.util;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Properties;

public class DBUtil1 {
    // 数据库的连接信息
    private static  String url;
    private static  String user;
    private static  String password;
    private static  String drivername;
    // 引用数据类型的变量默认值为null
    public static Connection connection;
    private static PreparedStatement pst;
    private static ResultSet rs;

    /**
     *     静态代码块只会执行一次
     */
    static {
        try(InputStream in = DBUtil.class.getClassLoader().getResourceAsStream("db.properties")) {
            Properties properties = new Properties();
            properties.load(in);
            url = properties.getProperty("jdbc_url");
            user = properties.getProperty("jdbc_user");
            password = properties.getProperty("jdbc_password");
            drivername = properties.getProperty("jdbc_drivername");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    
    /**
     * 连接数据库
     */
    public static Connection getConnection() {
        try {
            Class.forName(drivername);
            connection = DriverManager.getConnection(url, user, password);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return connection;
    }

}