Set set1 =new HashSet();
set1.add(111);
set1.add(11.11);
set1.add("sss");
for( Iterator it = set1.iterator(); it.hasNext(); )
{
System.out.println("value="+it.next().toString());
}
set可以存放各种元素,然后使用迭代器进行遍历,输出
//对于一些java.util.Collections
//以下是java.util.Collections.singleton()方法的声明。
//
//public static <T> Set<T> singleton(T o)
String init[] = { "One", "Two", "Three", "One", "Two", "Three" };
// create two lists
List list1 = new ArrayList(Arrays.asList(init));
List list2 = new ArrayList(Arrays.asList(init));
// remove from list1
list1.remove("One"); //只会移除第一个元素
list1.add("One");
// list1.removeAll("One"); 这样写是不对的,因为removeAll中 需要的是Collection类型的
System.out.println("List1 value: "+list1);
// remove from list2 using singleton
list2.removeAll(Collections.singleton("One"));
System.out.println(Collections.singleton("One"));
System.out.println("The SingletonList is :"+list2);
输出:
List1 value: [Two, Three, One, Two, Three, One]
[One] // System.out.println(Collections.singleton("One")) 这个的输出
The SingletonList is :[Two, Three, Two, Three]