List集合中的对象判断某个字段是否重复

对象和字段自定义

 /**
     * 判断List<Knowledge>的对象code是否有重复，有重复true
     *
     * @param orderList
     * @return
     */
    private Boolean knowledgeIsRepeat(List<Knowledge> orderList) {
        Set<Knowledge> set = new TreeSet<Knowledge>(new Comparator<Knowledge>() {
            public int compare(Knowledge a, Knowledge b) {
                // 字符串则按照asicc码升序排列
                return a.getCode().compareTo(b.getCode());
            }
        });
        set.addAll(orderList);
        if (set.size() < orderList.size()) {
            return true;
        }
        return false;
    }

合中的对象按照某个字段去重实现

https://www.iteye.com/blog/zysnba-2419940