使用 Collection 类的 collection.remove() 方法来删除集合中的指定的元素

完整代码

import java.util.*;public class Main {public static void main(String [] args) {   System.out.println( "集合实例!\n" ); int size;HashSet collection = new HashSet ();String str1 = "Red", str2 = "Yellow", str3 = "White", str4 = "Blue";  Iterator iterator;collection.add(str1);    collection.add(str2);   collection.add(str3);   collection.add(str4);System.out.print("集合数据: ");  iterator = collection.iterator();     while (iterator.hasNext()){System.out.print(iterator.next() + " ");  }System.out.println();collection.remove(str2);System.out.println("删除之后 [" + str2 + "]\n");System.out.print("现在集合的数据是: ");iterator = collection.iterator();     while (iterator.hasNext()){System.out.print(iterator.next() + " ");  }System.out.println();size = collection.size();System.out.println("集合大小: " + size + "\n");}
}

结果输出

集合实例!集合数据: Red Yellow White  Blue  
删除之后 [Yellow ]现在集合的数据是: Red White  Blue  
集合大小: 3