mysql-连接池。 DriverManager.getConnection()返回对象不变。。

<code>public static void main(String[] args) throws Throwable {        JDBCUtil jdbc=new JDBCUtil();        jdbc.getConnection();        jdbc.getConnection();           }public  void getConnection()  {        Connection conn = null;        try {            Class.forName("com.mysql.jdbc.Driver");            conn = DriverManager.getConnection(URL, USER, PASSWORD);            System.out.println(conn);        } catch (SQLException | ClassNotFoundException e) {            e.printStackTrace();        }finally{            try {                if(conn!=null) conn.close();            } catch (SQLException e) {                e.printStackTrace();            }finally{                System.out.println(conn);            }        }    }</code>

<code>com.mysql.jdbc.JDBC4Connection@446cdf90com.mysql.jdbc.JDBC4Connection@446cdf90com.mysql.jdbc.JDBC4Connection@1de0aca6com.mysql.jdbc.JDBC4Connection@1de0aca6</code>