Java中的 TemporalAdjusters firstDayOfYear() 方法及示例

TemporalAdjusters 类的firstDayOfYear()方法用于返回“一年中的第一天”TemporalAdjuster 对象，该对象返回设置为一年中第一天的新 Date 对象。

句法：

public static TemporalAdjuster firstDayOfYear()

参数：此方法不接受任何内容。

返回值：该方法返回年份调整器的第一天，不为空。

下面的程序说明了 TemporalAdjusters.firstDayOfYear() 方法：
方案一：

// Java program to demonstrate
// TemporalAdjusters.firstDayOfYear()
  
import java.time.LocalDate;
import java.time.temporal.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // get TemporalAdjuster with first day
        // of the year adjuster
        TemporalAdjuster temporalAdjuster
            = TemporalAdjusters.firstDayOfYear();
  
        // using adjuster for local date-time
        LocalDate localDate
            = LocalDate.of(2012, 05, 31);
        LocalDate firstDayOfYear
            = localDate.with(temporalAdjuster);
  
        // print
        System.out.println("First day of the "
                           + "year for localdate "
                           + localDate + ": "
                           + firstDayOfYear);
    }
}

输出：

First day of the year for localdate 2012-05-31: 2012-01-01

方案二：

// Java program to demonstrate
// TemporalAdjusters.firstDayOfYear() method
  
import java.time.LocalDate;
import java.time.temporal.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // get TemporalAdjuster with first day
        // of the year adjuster
        TemporalAdjuster temporalAdjuster
            = TemporalAdjusters.firstDayOfYear();
  
        // using adjuster for local date time
        LocalDate localDate
            = LocalDate.of(2000, 12, 21);
        LocalDate firstDayOfYear
            = localDate.with(temporalAdjuster);
  
        // print
        System.out.println("First day of the "
                           + "year for localdate "
                           + localDate + ": "
                           + firstDayOfYear);
    }
}

输出：

First day of the year for localdate 2000-12-21: 2000-01-01

参考资料：https: Java