java List集合去重保持原顺序

  • 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[] { "a", "c", "aa", "a", "b", "d" };
    // 利用LinkedHashSet去重
    Collection collection = new LinkedHashSet(Arrays.asList(arr));
    System.out.println("(LinkedHashSet) distinct words: " + collection);
    // 转为list
    List list = new ArrayList(collection);
    

    输出:

    (LinkedHashSet) distinct words: [a, c, aa, b, d]

  • HashSet去重方法,去重后顺序打乱(重复数据只保留一条)

    String[] arr = new String[] { "a", "c", "aa", "a", "b", "d" };
    // 利用HashSet去重
    HashSet h = new HashSet(Arrays.asList(arr));
    System.out.println("(HashSet) distinct words: " + collection);
    // 转为list
    List list2 = new ArrayList(collection);
    

    输出:

    (HashSet) distinct words: [a, c, aa, b, d]

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