Java Collections enumeration()用法及代碼示例

java.util.Collections類的enumeration()方法用於返回指定集合上的枚舉。這提供了與需要枚舉作為輸入的舊式API的互操作性。

用法:

public static  Enumeration enumeration(Collection c)

參數：此方法將集合c作為要返回其枚舉的參數。

返回值：此方法返回指定集合的枚舉。

以下示例說明了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); 
        } 
    } 
}

輸出：

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); 
        } 
    } 
}

輸出：

List: [20, 30, 40]

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

相關用法

注：本文由純淨天空篩選整理自RohitPrasad3大神的英文原創作品 Collections enumeration() method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。