Java 中的 Collection 接口函数

Collection接口是构建收集框架的基础。它声明了所有集合将拥有的核心方法。下表总结了这些方法。

Collection 示例

以下是一个示例，说明上述收集方法的各种类实现中的几种方法-

import java.util.*;
public class CollectionsDemo {

   public static void main(String[] args) {
      //数组列表 
      List a1 = new ArrayList();
      a1.add("Learnfk");
      a1.add("Mahnaz");
      a1.add("Ayan");
      System.out.println(" ArrayList Elements");
      System.out.print("\t" + a1);

      //链表
      List l1 = new LinkedList();
      l1.add("Learnfk");
      l1.add("Mahnaz");
      l1.add("Ayan");
      System.out.println();
      System.out.println(" LinkedList Elements");
      System.out.print("\t" + l1);

      //哈希集
      Set s1 = new HashSet(); 
      s1.add("Learnfk");
      s1.add("Mahnaz");
      s1.add("Ayan");
      System.out.println();
      System.out.println(" Set Elements");
      System.out.print("\t" + s1);

      //哈希映射
      Map m1 = new HashMap(); 
      m1.put("Learnfk", "8");
      m1.put("Mahnaz", "31");
      m1.put("Ayan", "12");
      m1.put("Daisy", "14");
      System.out.println();
      System.out.println(" Map Elements");
      System.out.print("\t" + m1);
   }
}

这将产生以下输出-

 ArrayList Elements
	[Learnfk, Mahnaz, Ayan]
 LinkedList Elements
	[Learnfk, Mahnaz, Ayan]
 Set Elements
	[Ayan, Learnfk, Mahnaz]
 Map Elements
	{Daisy=14, Ayan=12, Learnfk=8, Mahnaz=31}