Java中的 YearMonth isSupported(TemporalField) 方法及示例

YearMonth类的isSupported(TemporalField)方法用于检查指定字段是否被 YearMonth 类支持，即使用该方法我们可以检查是否可以针对指定字段查询此 YearMonth 对象。

ChronoField 支持的字段有：

• MONTH_OF_YEAR
• PROLEPTIC_MONTH
• YEAR_OF_ERA
• 年
• 时代

所有其他 ChronoField 实例将返回 false。

句法：

public boolean isSupported(TemporalField field)

参数：此方法只接受一个参数字段，该字段表示要检查的字段。

返回值：如果此 YearMonth 支持该字段，则此方法返回布尔值 true，否则返回 false。

下面的程序说明了 isSupported(TemporalField) 方法：

方案一：

// Java program to demonstrate
// YearMonth.isSupported(TemporalField) method
  
import java.time.*;
import java.time.temporal.*;
  
public class GFG {
    public static void main(String[] args)
    {
        // Create a YearMonth object
        YearMonth thisYearMonth = YearMonth.of(2017, 8);
  
        // print instance
        System.out.println("YearMonth :"
                           + thisYearMonth);
  
        // apply isSupported() method
        boolean value
            = thisYearMonth.isSupported(
                ChronoField.PROLEPTIC_MONTH);
  
        // print result
        System.out.println("PROLEPTIC_MONTH Field is supported by YearMonth class: "
                           + value);
    }
}

输出：

YearMonth :2017-08
PROLEPTIC_MONTH Field is supported by YearMonth class: true

方案二：

// Java program to demonstrate
// YearMonth.isSupported(TemporalField) method
  
import java.time.*;
import java.time.temporal.*;
  
public class GFG {
    public static void main(String[] args)
    {
        // Create a YearMonth object
        YearMonth thisYearMonth = YearMonth.of(2017, 8);
  
        // print instance
        System.out.println("YearMonth :"
                           + thisYearMonth);
  
        // apply isSupported() method
        boolean value
            = thisYearMonth.isSupported(
                ChronoField.HOUR_OF_DAY);
  
        // print result
        System.out.println("HOUR_OF_DAY Field is supported by YearMonth class: "
                           + value);
    }
}

输出：

YearMonth :2017-08
HOUR_OF_DAY Field is supported by YearMonth class: false

参考：
Java Java )