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);
	
} 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();
}