Java中HashSet如何进行去重操作呢？

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Java中HashSet如何进行去重操作呢？

下文讲述java中HashSet进行去重的四种方法分享，如下所示:

LinkedHashSet去重

去重后保持原有顺序（重复数据只保留一条）

String[] arr = new String[] {"java", "265", "com", "very", "good", "web"};   
Collection noDups = new LinkedHashSet(Arrays.asList(arr));   
System.out.println("(LinkedHashSet) distinct words:    " + noDups); 

HashSet去重方法一

去重后顺序打乱（重复数据只保留一条）

String[] arr = new String[] {"java", "265", "com", "very", "good", "web"};
Collection noDups = new HashSet(Arrays.asList(arr));   
System.out.println("(HashSet) distinct words:    " + noDups);   

HashSet去重方法二

去重后顺序打乱（重复数据只保留一条）

String[] arr = new String[] {"java", "265", "com", "very", "good", "web"};
Set s = new HashSet();   
for (String a : arr)   
{   
 if (!s.add(a))   
 {   
 System.out.println("Duplicate detected: " + a);   
 }   
}   
System.out.println(s.size() + " distinct words: " + s); 

HashSet去重方法三

去重后顺序打乱(相同的数据一条都不保留，取唯一)

String[] arr = new String[] {"java", "265", "com", "very", "good", "web"};
Set uniques = new HashSet();   
Set dups = new HashSet();   
for (String a : arr)   
{   
 {   
 if (!uniques.add(a))   
 dups.add(a);   
 }   
}   
uniques.removeAll(dups);   
System.out.println("Unique words:    " + uniques);   
System.out.println("Duplicate words: " + dups);