import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

public class 迭代器 {
	static ArrayList<String> arrayList = new ArrayList<>();

	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		Collection<String> aCollection = new ArrayList<String>();
		aCollection.add("hello");
		aCollection.add("world");
		aCollection.add("java");
		Iterator<String> it = aCollection.iterator();
		System.out.println(it.next());
		System.out.println(it.next());
		System.out.println(it.next());

		arrayList.add("hello");
		arrayList.add("world");
		arrayList.add("java");
		Iterator<String> it2 = arrayList.iterator();
		System.out.println(it2.next());
		System.out.println(it2.next());
		System.out.println(it2.next());
		System.out.println("集合遍历");
		/**
		 * 普通遍历
		 */
		for (int i = 0; i < arrayList.size(); i++) {
			System.out.println(arrayList.get(i));
		}
		System.out.println("for遍历");
		/**
		 * 增强遍历
		 */
		for (String s : arrayList) {
			System.out.println(s);
		}
		System.out.println("增强for遍历");
	}

}

输出如下

分别是迭代器

for

foreach

hello
world
java
hello
world
java
集合遍历
hello
world
java
for遍历
hello
world
java
增强for遍历