set集合迭代

1.迭代遍历

Set<String> set = new HashSet<String>();
Iterator<String> it = set.iterator();
while (it.hasNext()) {
  String str = it.next();
  System.out.println(str);
}

2.for循环遍历：

for (String str : set) {
      System.out.println(str);
}

3.优点还体现在泛型 假如 set中存放的是Object

Set<Object> set = new HashSet<Object>();
for循环遍历：
for (Object obj: set) {
   if(obj instanceof Integer){
      int aa= (Integer)obj;
   }else if(obj instanceof String){
      String aa = (String)obj
   }
   ........
}