Java LocalDate类| isSupported（）方法与示例

LocalDate类isSupported()方法 (LocalDate Class isSupported() method)

Syntax:

句法：

public boolean isSupported (TemporalField t_field);
public boolean isSupported (TemporalUnit t_unit);

isSupported() method is available in java.time package.
isSupported()方法在java.time包中可用。
isSupported (TemporalField t_field) method is used to check whether the given field is supported or not.
isSupported(TemporalField t_field)方法用于检查是否支持给定的字段。
isSupported (TemporalUnit t_unit) method is used to identify whether the given unit is supported or not.
isSupported(TemporalUnit t_unit)方法用于标识是否支持给定的单位。
These methods don't throw an exception at the time of checking status.
这些方法在检查状态时不会引发异常。
These are non-static methods and it is accessible with class objects and if we try to access these methods with class name then we will get an error.
这些是非静态方法，可通过类对象访问，如果尝试使用类名访问这些方法，则会收到错误消息。

Parameter(s):

参数：

In the first cases, isSupported (TemporalField t_field),
在第一种情况下，isSupported(TemporalField t_field)，
- TemporalField t_field – represents the field to be checked for support.
- TemporalField t_field –表示要检查支持的字段。
In the second cases, atStartOfDay(ZoneId zo),
在第二种情况下，在atStartOfDay(ZoneId zo)，
- TemporalUnit t_unit – represents the unit to be checked for support.
- TemporalUnit t_unit –表示要检查支持的单位。

Return value:

返回值：

In both the cases, the return type of the method is boolean,

在这两种情况下，方法的返回类型均为boolean 。

In the first case, it returns true when the given field is supported otherwise it returns false.
在第一种情况下，当支持给定字段时，它返回true，否则返回false。
In the second case, it returns true when the given unit is supported otherwise it returns false.
在第二种情况下，当支持给定单元时，它返回true，否则返回false。

Example:

例：

// Java program to demonstrate the example 
// of isSupported() method of LocalDate
import java.time.*;
import java.time.temporal.*;
public class IsSupportedOfLocalDate {
public static void main(String args[]) {
// Instantiates two LocalDate
LocalDate l_da1 = LocalDate.parse("2007-04-04");
LocalDate l_da2 = LocalDate.now();
// Display l_da1,l_da2
System.out.println("LocalDate l_da1 and l_da2: ");
System.out.println("l_da1: " + l_da1);
System.out.println("l_da2: " + l_da2);
System.out.println();
// Here, this method checks whether
// the given field DAY_OF_WEEK is 
// supported or not
boolean status = l_da1.isSupported(ChronoField.DAY_OF_WEEK);
// Display status
System.out.println("l_da1.isSupported(ChronoField.DAY_OF_WEEK): " + status);
// Here, this method checks whether
// the given unit DECADES is supported
// or not
status = l_da2.isSupported(ChronoUnit.DECADES);
// Display status
System.out.println("l_da2.isSupported(ChronoUnit.DECADES): " + status);
}
}

Output

输出量

LocalDate l_da1 and l_da2: 
l_da1: 2007-04-04
l_da2: 2020-06-03l_da1.isSupported(ChronoField.DAY_OF_WEEK): true
l_da2.isSupported(ChronoUnit.DECADES): true