Java中的 ZoneOffset compareTo(ZoneOffset) 方法及示例

Java.time 包中ZoneOffset 类的compareTo(ZoneOffset)方法用于比较作为参数传递给此 ZoneOffset 实例的另一个 ZoneOffset 实例。此方法返回一个整数值，它是比较器值。

句法：

public int compareTo(ZoneOffset anotherZoneOffset)

参数：此方法接受要与此 ZoneOffset 实例进行比较的参数anotherZoneOffset 。

返回值：该方法返回一个整数值，如下所示：

• 如果此实例大于作为参数传递的实例，则返回正值
• 如果此实例等于作为参数传递的实例，则返回零 (0)
• 如果此实例小于作为参数传递的实例，则返回负值。

  异常：如果作为参数传递的 anotherZoneOffset 为 null，则此方法抛出NullPointerException 。

  下面的示例说明了 ZoneOffset.compareTo() 方法：

  示例 1：

  // Java code to illustrate compareTo() method
    
  import java.time.*;
    
  public class GFG {
      public static void main(String[] args)
      {
    
          // Get the ZoneOffset instance
          ZoneOffset zoneOffset1
              = ZoneOffset.ofHours(5);
          System.out.println("ZoneOffset 1: "
                             + zoneOffset1);
    
          // Get the ZoneOffset instance
          ZoneOffset zoneOffset2
              = ZoneOffset.ofHours(5);
          System.out.println("ZoneOffset 2: "
                             + zoneOffset2);
    
          // Get the ZoneOffset instance
          ZoneOffset zoneOffset3
              = ZoneOffset.ofHours(3);
          System.out.println("ZoneOffset 3: "
                             + zoneOffset3);
    
          // Using compareTo() method
          System.out.println("ZoneOffset 1 "
                             + "compared to ZoneOffset 2: "
                             + zoneOffset1.compareTo(zoneOffset2));
    
          // Using compareTo() method
          System.out.println("ZoneOffset 1 "
                             + "compared to ZoneOffset 3: "
                             + zoneOffset1.compareTo(zoneOffset3));
    
          // Using compareTo() method
          System.out.println("ZoneOffset 3 "
                             + "compared to ZoneOffset 1: "
                             + zoneOffset3.compareTo(zoneOffset1));
      }
  }
  

  输出：

  ZoneOffset 1: +05:00
  ZoneOffset 2: +05:00
  ZoneOffset 3: +03:00
  ZoneOffset 1 compared to ZoneOffset 2: 0
  ZoneOffset 1 compared to ZoneOffset 3: -7200
  ZoneOffset 3 compared to ZoneOffset 1: 7200
  

  示例 2：显示 NullPointerException

  // Java code to illustrate compareTo() method
    
  import java.time.*;
    
  public class GFG {
      public static void main(String[] args)
      {
    
          try {
              // Get the ZoneOffset instance
              ZoneOffset zoneOffset
                  = ZoneOffset.ofHours(3);
              System.out.println("ZoneOffset: "
                                 + zoneOffset);
    
              // Using compareTo() method
              System.out.println("ZoneOffset "
                                 + "compared to null: ");
    
              zoneOffset.compareTo(null);
          }
          catch (Exception e) {
              System.out.println(e);
          }
      }
  }
  

  输出：

  ZoneOffset: +03:00
  ZoneOffset compared to null: 
  java.lang.NullPointerException
  

  参考： Oracle 文档