package com.wangg;

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

public class Dome02 {
    public static void main(String[] args) {
        Collection collection = new ArrayList();
        collection.add(15);
        collection.add(16);
        collection.add(17);
        collection.add(18);

        //对集合遍历（就是对集合中的元素进行查看）
        //1.普通for循环
        //2.增强for循环
        for (Object m:collection){
            System.out.println(m);
        }
        System.out.println("----------------------");
        //3.
        Iterator it = collection.iterator();
        while (it.hasNext()){//hasNext代表是否有下一个
            System.out.println((it.next()));
        }



    }
}

Colleation遍历