Java LocalDateTime类| 带示例的compareTo（）方法

LocalDateTime类compareTo()方法 (LocalDateTime Class compareTo() method)

compareTo() method is available in java.time package.
compareTo()方法在java.time包中可用。
compareTo() method is used to compare this date-time object to the given date-time object.
compareTo()方法用于将此日期时间对象与给定的日期时间对象进行比较。
compareTo() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
compareTo()方法是一种非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。
compareTo() method does not throw an exception at the time of comparing.
compareTo()方法在比较时不会引发异常。

Syntax:

句法：

    public int compareTo(ChronoLocalDateTime l_datetime) ;

Parameter(s):

参数：

ChronoLocalDateTime l_datetime – represents the object to be compared to this LocalDateTime.
ChronoLocalDateTime l_datetime –表示要与此LocalDateTime比较的对象。

Return value:

返回值：

The return type of this method is int, it may return anyone of the given values.

此方法的返回类型为int ，它可以返回任何给定值。

When (this LocalDateTime) < (ChronoLocalDateTime l_datetime), it returns -1.
当(this LocalDateTime)<(ChronoLocalDateTime l_datetime)时，它返回-1。
When (this LocalDateTime) > (ChronoLocalDateTime l_datetime), it returns 1.
当(this LocalDateTime)>(ChronoLocalDateTime l_datetime)时，它返回1。

Example:

例：

// Java program to demonstrate the example 
// of int compareTo(ChronoLocalDateTime l_datetime) 
// method of LocalDateTime
import java.time.*;
public class CompareToOfLocalDateTime {
public static void main(String args[]) {
// Instantiates two LocalDateTime
LocalDateTime da_ti1 = LocalDateTime.parse("2005-10-05T10:10:10");
LocalDateTime da_ti2 = LocalDateTime.now();
// Display da_ti1, da_ti2
System.out.println("LocalDateTime da_ti1 and da_ti2: ");
System.out.println("da_ti1: " + da_ti1);
System.out.println("da_ti2: " + da_ti2);
System.out.println();
// Here, this method compares two date-time
// objects i.e. here it returns the 
// difference of first non-matching field
// in both the objects like first non-match
// field is year da_ti1 = 2005 and da_ti2
// = 2020 so the value (2005-2020 = -15)
// -15 will be returned
int compare = da_ti1.compareTo(da_ti2);
// Display compare
System.out.println("da_ti1.compareTo(da_ti2): " + compare);
// Here, this method compares two date-time
// objects i.e. here it returns the 
// difference of first non-matching field
// in both the objects like first non-match
// field is year da_ti2 = 2020 and da_ti2
// = 2005 so the value (2020 - 2005 = 15)
// 15 will be returned
compare = da_ti2.compareTo(da_ti1);
// Display compare
System.out.println("da_ti2.compareTo(da_ti1): " + compare);
// Here, this method compares two date-time
// objects i.e. here it returns 0 because
// date-time are same in both the compared
// objects
compare = da_ti1.compareTo(da_ti1);
// Display compare
System.out.println("da_ti1.compareTo(da_ti1): " + compare);
}
}

Output

输出量

LocalDateTime da_ti1 and da_ti2: 
da_ti1: 2005-10-05T10:10:10
da_ti2: 2020-06-04T08:35:27.674928da_ti1.compareTo(da_ti2): -15
da_ti2.compareTo(da_ti1): 15
da_ti1.compareTo(da_ti1): 0