Java ZoneOffset compareTo(ZoneOffset)用法及代码示例

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ZoneOffset的另一个实例。此方法返回一个整数值，该整数值是比较器值。

用法:

public int compareTo(ZoneOffset anotherZoneOffset)

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

返回值：此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，则此方法引发NullPointerException。

以下示例说明了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 Doc