collection的常用三种遍历方式

1.foreach遍历（无简化）

list.forEach(new Consumer<String>() {
    @Override
    public void accept(String s) {
        System.out.println(s);
    }
});

简化版（lambda表达式)

 list.forEach( s3 ->System.out.println(s3)         
        );

2.增强for

 for (String string : list) {
            System.out.println(string);
        }

3.迭代器遍历

Iterator<String> it = list.iterator();
        while(it.hasNext()){
            String ss= it.next();
            System.out.println(ss);
        }