Java中对 set 的遍历方式

Java中对 set 的遍历方式

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1.迭代遍历： 

Set<String> set = new HashSet<String>(); 

//Set<Integer> set = new HashSet<Integer>(); 

//Set<Map<String,Object>>  buildingSet = new HashSet<>();

Iterator<String> it = set.iterator(); 

while (it.hasNext()) { 

  String str = it.next(); 

  System.out.println(str); 

} 

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2.for循环遍历： 

for (String str : set) { 

      System.out.println(str); 

} 

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3.for循环遍历:假如 set中存放的是Object 

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

for (Object obj: set) { 

      if(obj instanceof Integer){ 

                int aa= (Integer)obj; 

            }else if(obj instanceof String){ 

              String aa = (String)obj 

            } 

}