Java Collections enumeration()用法及代码示例

java.util.Collections类的enumeration()方法用于返回指定集合上的枚举。这提供了与需要枚举作为输入的旧式API的互操作性。

用法:

public static  Enumeration enumeration(Collection c)

参数：此方法将集合c作为要返回其枚举的参数。

返回值：此方法返回指定集合的枚举。

以下示例说明了enumeration()方法

示例1:

// Java program to demonstrate 
// enumeration() method 
// for String value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // creating object of List<String> 
            List<String> arrlist = new ArrayList<String>(); 
  
            // Adding elemnet to srclst 
            arrlist.add("Ram"); 
            arrlist.add("Gopal"); 
            arrlist.add("Verma"); 
  
            // Print the list 
            System.out.println("List: " + arrlist); 
  
            // creating object of type Enumeration<String> 
            Enumeration<String> e = Collections.enumeration(arrlist); 
  
            // Print the Enumeration 
            System.out.println("\nEnumeration over list: "); 
  
            // print the enumeration 
            while (e.hasMoreElements()) 
                System.out.println("Value is: " + e.nextElement()); 
        } 
  
        catch (IllegalArgumentException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
  
        catch (NoSuchElementException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

List: [Ram, Gopal, Verma]

Enumeration over list: 
Value is: Ram
Value is: Gopal
Value is: Verma

示例2:

// Java program to demonstrate 
// enumeration() method 
// for Integer value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // creating object of List<Integer> 
            List<Integer> arrlist = new ArrayList<Integer>(); 
  
            // Adding elemnet to srclst 
            arrlist.add(20); 
            arrlist.add(30); 
            arrlist.add(40); 
  
            // Print the list 
            System.out.println("List: " + arrlist); 
  
            // creating object of type Enumeration<Integer> 
            Enumeration<Integer> e = Collections.enumeration(arrlist); 
  
            // Print the Enumeration 
            System.out.println("\nEnumeration over list: "); 
  
            // print the enumeration 
            while (e.hasMoreElements()) 
                System.out.println("Value is: " + e.nextElement()); 
        } 
  
        catch (IllegalArgumentException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
  
        catch (NoSuchElementException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

List: [20, 30, 40]

Enumeration over list: 
Value is: 20
Value is: 30
Value is: 40

相关用法

注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 Collections enumeration() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。