Java中的 UUID compareTo() 方法及示例

Java中UUID 类的compareTo()方法用于将一个 UUID 值与另一个指定的 UUID 进行比较。如果此 UUID 小于该值，则返回 -1，如果此 UUID 等于该值，则返回 0，如果此 UUID 大于该值，则返回 1。

句法：

UUID_1.compareTo(UUID_2)

参数：该方法采用一个参数UUID_2 ，与 UUID_1 进行比较。

返回值：该方法返回-1、0 或 1，具体取决于此 UUID_1 是否小于、等于或大于另一个 UUID_2。

下面的程序说明了 compareTo() 方法的工作：

程序 1：检查两个 UUID 是否相等。

// Java code to illustrate compareTo() method
  
import java.util.*;
  
public class UUID_Demo {
    public static void main(String[] args)
    {
  
        // Creating two UUIDs
        UUID UUID_1
            = UUID
                  .fromString(
                      "5fc03087-d265-11e7-b8c6-83e29cd24f4c");
  
        UUID UUID_2
            = UUID
                  .fromString(
                      "5fc03087-d265-11e7-b8c6-83e29cd24f4c");
  
        // Displaying the UUID values
        System.out.println("UUID_1: "
                           + UUID_1.clockSequence());
        System.out.println("UUID_2: "
                           + UUID_2.clockSequence());
  
        // Comparing both the UUIDs
        System.out.println("Comparison Value: "
                           + UUID_1.compareTo(UUID_2));
    }
}

输出：

UUID_1: 14534
UUID_2: 14534
Comparison Value: 0

方案二：当UUID_1小于UUID_2时，方法返回-1。

// Java code to illustrate compareTo() method
  
import java.util.*;
  
public class UUID_Demo {
    public static void main(String[] args)
    {
  
        // Creating two UUIDs
        UUID UUID_1
            = UUID
                  .fromString(
                      "58e0a7d7-eebc-11d8-9669-0800200c9a66");
  
        UUID UUID_2
            = UUID
                  .fromString(
                      "5fc03087-d265-11e7-b8c6-83e29cd24f4c");
  
        // Displaying the UUID values
        System.out.println("UUID_1: "
                           + UUID_1.clockSequence());
        System.out.println("UUID_2: "
                           + UUID_2.clockSequence());
  
        // Comparing both the UUIDs
        System.out.println("Comparison Value: "
                           + UUID_1.compareTo(UUID_2));
    }
}

输出：

UUID_1: 5737
UUID_2: 14534
Comparison Value: -1

方案3：当UUID_1大于UUID_2时，方法返回1。

// Java code to illustrate compareTo() method
  
import java.util.*;
  
public class UUID_Demo {
    public static void main(String[] args)
    {
  
        // Creating two UUIDs
        UUID UUID_1
            = UUID
                  .fromString(
                      "5fc03087-d265-11e7-b8c6-83e29cd24f4c");
  
        UUID UUID_2
            = UUID
                  .fromString(
                      "58e0a7d7-eebc-11d8-9669-0800200c9a66");
  
        // Displaying the UUID values
        System.out.println("UUID_1: "
                           + UUID_1.clockSequence());
        System.out.println("UUID_2: "
                           + UUID_2.clockSequence());
  
        // Comparing both the UUIDs
        System.out.println("Comparison Value: "
                           + UUID_1.compareTo(UUID_2));
    }
}

输出：

UUID_1: 14534
UUID_2: 5737
Comparison Value: 1