Think in Java(八)：持有对象

public class ListIteration {
	public static void main(String[] args) {
		List<Pet> pets = Pets.arrayList(8);
		ListIterator<Pet> it = pets.listIterator();
		
		// Forwards:
		while (it.hasNext()){
			System.out.print(it.next() + ", " + it.nextIndex() + ", " + it.previousIndex() + "; ");
		}
		
		// Backwards:
		while (it.hasPrevious()){
			System.out.print(it.previous().id() + " ");
		}
	}
}

3. TreeSet中的元素是排序的，默认按照字典升序，当然我们可以自己传入一个比较器来自定义排序。

public class UniqueWordsAlphabetic {
	public static void main(String[] args) {
		Set<String> words = new TreeSet<String>(String.CASE_INSENSITIVE_ORDER);
		words.add("a");
		words.add("c");
		words.add("B");
		System.out.println(words);
	}
}

Think in Java(八)：持有对象

原文：http://blog.csdn.net/zdp072/article/details/43650219