Java - 枚举compareTo() 方法

描述

Java Enum compareTo() 方法比较此枚举与指定对象的顺序。枚举常量只能与相同枚举类型的其他枚举常量进行比较。

声明

以下是java.lang.Enum.compareTo() 方法的声明

public final int compareTo(E o)

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参数

o − 这是要比较的对象。

返回值

此方法返回一个负整数、零或正整数，具体取决于此对象小于、等于或大于指定对象。

异常

无

比较枚举值示例

以下示例演示了如何使用 compareTo() 方法比较相同枚举类型的各种枚举值，以检查大于 0 的结果。

Open Compiler

package com.tutorialspoint;

// enum showing topics covered under Tutorials
enum Tutorials {  
   Java, HTML, Python; 
}  
public class EnumDemo { 
   public static void main(String args[]) { 
      Tutorials t1, t2;     
      t1 = Tutorials.Java; 
      t2 = Tutorials.HTML;     
      if(t1.compareTo(t2) > 0) {
         System.out.println(t2 + " completed before " + t1); 
      } else if(t1.compareTo(t2) < 0) {
         System.out.println(t1 + " completed before " + t2); 
      } else if(t1.compareTo(t2) == 0) { 
         System.out.println(t1 + " completed with " + t2); 
      }
   } 
}

输出

让我们编译并运行上述程序，这将产生以下结果：

Java completed before HTML

比较枚举值示例

以下示例演示了如何使用 compareTo() 方法比较相同枚举类型的各种枚举值，以检查等于 0 的结果。

Open Compiler

package com.tutorialspoint;

// enum showing topics covered under Tutorials
enum Tutorials {  
   Java, HTML, Python; 
}  
public class EnumDemo { 
   public static void main(String args[]) {
 
      Tutorials t1, t2; 
    
      t1 = Tutorials.HTML; 
      t2 = Tutorials.HTML; 
    
      if(t1.compareTo(t2) > 0) {
         System.out.println(t2 + " completed before " + t1); 
      } else if(t1.compareTo(t2) < 0) {
         System.out.println(t1 + " completed before " + t2); 
      } else if(t1.compareTo(t2) == 0) { 
         System.out.println(t1 + " completed with " + t2); 
      }
   } 
}

输出

让我们编译并运行上述程序，这将产生以下结果：

HTML completed with HTML

比较枚举值示例

以下示例演示了如何使用 compareTo() 方法比较相同枚举类型的各种枚举值，以检查小于 0 的结果。

Open Compiler

package com.tutorialspoint;

// enum showing topics covered under Tutorials
enum Tutorials {  
   Java, HTML, Python; 
}  
public class EnumDemo { 
   public static void main(String args[]) {
 
      Tutorials t1, t2; 
    
      t1 = Tutorials.HTML; 
      t2 = Tutorials.Python; 
    
      if(t1.compareTo(t2) > 0) {
         System.out.println(t2 + " completed before " + t1); 
      } else if(t1.compareTo(t2) < 0) {
         System.out.println(t1 + " completed before " + t2); 
      } else if(t1.compareTo(t2) == 0) { 
         System.out.println(t1 + " completed with " + t2); 
      }
   } 
}

输出

让我们编译并运行上述程序，这将产生以下结果：

HTML completed before Python

java_lang_enum.htm

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