java中Date日期类型的大小比较

方法一:

java.util.Date类实现了Comparable接口，可以直接调用Date的compareTo()方法来比较大小

String beginTime = "2018-07-28 14:42:32";
String endTime = "2018-07-29 12:26:32";SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");try {Date date1 = format.parse(beginTime);Date date2 = format.parse(endTime);int compareTo = date1.compareTo(date2);System.out.println(compareTo);} catch (ParseException e) {e.printStackTrace();
}

compareTo()方法的返回值，date1小于date2返回-1，date1大于date2返回1，相等返回0

方法二：

通过Date自带的before()或者after()方法比较

String beginTime = "2018-07-28 14:42:32";
String endTime = "2018-07-29 12:26:32";SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");try {Date date1 = format.parse(beginTime);Date date2 = format.parse(endTime);boolean before = date1.before(date2);System.out.println(before); // trueboolean after = date1.after(date2);System.out.println(after); // false} catch (ParseException e) {e.printStackTrace();
}

before()或者after()方法的返回值为boolean类型

方法三：

通过调用Date的getTime()方法获取到毫秒数来进行比较

String beginTime = "2018-07-28 14:42:32";
String endTime = "2018-07-29 12:26:32";SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");try {Date date1 = format.parse(beginTime);Date date2 = format.parse(endTime);long beginMillisecond = date1.getTime();long endMillisecond = date2.getTime();System.out.println(beginMillisecond > endMillisecond);} catch (ParseException e) {e.printStackTrace();
}