[Java] Java中遍历集合的几种方式
Java对 set集合的遍历
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); }
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 } ........ }
3: 使用stream()遍历
Set<String> set = new HashSet<String>(); set.stream().forEach(System.out::println)