集合元素的遍历操作，使用迭代器Iterator接口

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

/**
 * @author xianyu
 * @version 1.0
 * @date 2019/12/29 21:24
 */
public class CollectionTest2 {

    public static void main(String[] args) {

        Collection coll = new ArrayList();
        coll.add("AA");
        coll.add(456);
        coll.add("Hello");
        coll.add("AA");
        coll.add(123);
        coll.add(new Person("Tom",23));
        coll.add(new Date());
        System.out.println(coll);
        System.out.println("********************");
        // 遍历方法1
        Iterator iterator = coll.iterator();
        while(iterator.hasNext()){  // hasNext():判断是否还有下一个元素
            System.out.println(iterator.next());  // //next():①指针下移 ②将下移以后集合位置上的元素返回
        }
        System.out.println("********************");

        // 遍历方法2
        for(Object obj : coll){
            System.out.println(obj);
        }
        System.out.println("********************");

        // 遍历方法3
        Iterator iter = coll.iterator();
        System.out.println(iter.next());
        System.out.println(iter.next());
        System.out.println(iter.next());
        System.out.println(iter.next());
        System.out.println(iter.next());
        System.out.println(iter.next());
        System.out.println(iter.next());
        //System.out.println(iter.next());  // "main" java.util.NoSuchElementException
        System.out.println("********************");


        // 删除Hello
        Iterator iter2 = coll.iterator();
        while(iter2.hasNext()){  // hasNext():判断是否还有下一个元素
            Object obj = iter2.next();
            if("Hello".equals(obj)){
                iter2.remove();
            }
        }
        System.out.println(coll);


    }

}

运行结果

[AA, 456, Hello, AA, 123, Person{name='Tom', age=23}, Sun Dec 29 21:48:13 CST 2019]
********************
AA
456
Hello
AA
123
Person{name='Tom', age=23}
Sun Dec 29 21:48:13 CST 2019
********************
AA
456
Hello
AA
123
Person{name='Tom', age=23}
Sun Dec 29 21:48:13 CST 2019
********************
AA
456
Hello
AA
123
Person{name='Tom', age=23}
Sun Dec 29 21:48:13 CST 2019
********************
[AA, 456, AA, 123, Person{name='Tom', age=23}, Sun Dec 29 21:48:13 CST 2019]