set集合的三种遍历方式

1.利用迭代器进行 ，迭代遍历：
Set<Object> sets = new HashSet<Object>();
Iterator<Object> it = set.iterator();
while (it.hasNext()) {
  String str = (String)it.next();
  System.out.println(str);
}

2.for循环遍历：
for (String str : sets) {
      System.out.println(str);
}

3.Set<Object> set = new HashSet<Object>();

foreach循环遍历：
for (Object obj: sets) {
      if(obj instanceof Integer){
                int aa= (Integer)obj;
             }else if(obj instanceof String){
               String aa = (String)obj
             }
              ……..

}