获取两个List的不同元素 博客分类： Java 两个List的不同元素

    /**
     * 获取两个List的不同元素
     * 
     * @param list1
     * @param list2
     * @return
     */
    private static List<String> getDiffrent4(List<String> list1, List<String> list2)
    {

        long st = System.nanoTime();

        Map<String, Integer> map = new HashMap<String, Integer>(list1.size() + list2.size());
        List<String> diff = new ArrayList<String>();

        List<String> maxList = list1;
        List<String> minList = list2;

        if (list2.size() > list1.size())
        {
            maxList = list2;
            minList = list1;
        }

        for (String string : maxList)
        {
            map.put(string, 1);
        }

        for (String string : minList)
        {
            Integer cc = map.get(string);
            if (cc != null)
            {
                map.put(string, ++cc);
                continue;
            }

            map.put(string, 1);
        }

        for (Map.Entry<String, Integer> entry : map.entrySet())
        {
            if (entry.getValue() == 1)
            {
                diff.add(entry.getKey());
            }
        }

        System.out.println("getDiffrent4 total times " + (System.nanoTime() - st));

        return diff;

    }