// 方法1
Date currentDate = new Date();
// 方法2
Calendar now = Calendar.getInstance();
// 方法3
long currentTime = System.currentTimeMillis();
System.out.println("当前时间:" + currentDate);
System.out.println("当前时间:" + now.getTime());
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS");
System.out.println("当前时间-格式化时间:" + sdf.format(currentDate));
System.out.println("当前时间-格式化时间:" + sdf.format(new Date(currentTime)));
System.out.println("当前时间-13位时间戳:" + currentDate.getTime());
System.out.println("当前时间-13位时间戳:" + now.getTimeInMillis());
System.out.println("当前时间-13位时间戳:" + currentTime);
效率比较:3>1>2
效率参考:https://www.cnblogs.com/zhujiabin/p/6168671.html?utm_source=itdadao&utm_medium=referral