主要有两种方式，代码如下：

//使用Calendar
Calendar now = Calendar.getInstance();
System.out.println("年：" + now.get(Calendar.YEAR));
System.out.println("月：" + (now.get(Calendar.MONTH) + 1));
System.out.println("日：" + now.get(Calendar.DAY_OF_MONTH));
System.out.println("时：" + now.get(Calendar.HOUR_OF_DAY));
System.out.println("分：" + now.get(Calendar.MINUTE));
System.out.println("秒：" + now.get(Calendar.SECOND));

//使用Date
Date d = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
System.out.println("当前时间：" + sdf.format(d));