筛选出重复数据和去除重复数据

1.
/**
 * 检查id是否重复，并把重复的id拿出来
 * @param list
 * @return
 */
@Override
public List<String> checkDTOId(List<WorkStatDTO> list) {
    List<String > str  = new ArrayList<>();
    List<String> workErrorId = new ArrayList<>();
    //把所有id放入String集合中
    for(WorkStatDTO strList : list){
        str.add(strList.getWorkStatId());
    }

    //用map方式来实现获得重复id

    Map<String,Integer> map = new HashMap<>();
    for(String strs :str){
        Integer i = 1;
        if(map.get(strs) != null){
            i = map.get(strs)+1;
        }
        map.put(strs,i);
        log.info("strs:"+strs+","+"i;"+i);
    }

    //再把重复数据拿出来
    for(String s:map.keySet()){
        if(map.get(s)>1){
            workErrorId.add(s);
            log.info("s:"+s);
        }
    }

    return workErrorId;
}


2.去除重复数据

List<String> str = workTimeService.checkDTO(workStatDTOS);
List<String > strList = new ArrayList<>();

//把返回有问题中重复的id，就只为一个
for(String string:str){
    if(!strList.contains(string)){
        strList.add(string);
    }
}

筛选出重复数据和去除重复数据

原文：https://www.cnblogs.com/yiyezhiqiuwuchen/p/12009070.html