Collection集合分析

1、Vector的用法

public class Client {
	public static void main(String[] args) {
		//實例化Vector併爲Vector插入元素
		Vector<String> vector = new Vector<>(5,3);
		vector.add("come");
		vector.addElement("on");
		vector.addAll(Arrays.asList("You are my apple".split(" ")));
		//Vector的四種迭代
		//1)Enumeration
		for (Enumeration<String> e = vector.elements();e.hasMoreElements();) {
			System.out.print(e.nextElement());
		}
		System.out.println();
		//2)foreach
		for(String s:vector){
			System.out.print(s);
		}
		System.out.println();
		//3)Iterator
		Iterator<String> iterator = vector.iterator();
		while(iterator.hasNext()){
			System.out.print(iterator.next());
			iterator.remove();
		}
		System.out.println();
		//elementData.length,elementCount
		System.out.println("capacity:"+vector.capacity()+"|size:"+vector.size());
		
		//4)ListIterator,可向前向後迭代，可增刪改
		Vector<String> vector2 = new Vector<String>(Arrays.asList("I'm a bit hungry".split(" ")));
		ListIterator<String> listIterator = vector2.listIterator(vector2.size());
		int count = 0;
		while(listIterator.hasPrevious()){
			String tmp = listIterator.previous();//cusor--
//			listIterator.set(tmp.toUpperCase());
//			listIterator.remove();
			if(vector2.size()<=10)
				listIterator.add("..."+count++);//cusor++
		}
		System.out.println(vector2);
	}
}

2、Vector、ArrayList、LinkedList的比較
相同點：都是List的子類，都可用Iterator和ListIterator迭代

不同點：1)Vector線程安全但低效，ArrayList不安全但高效

2)Vector和ArrayList內部用數組實現，而LinkedList內部維持一個雙端隊列