小编use*_*295的帖子

我如何使用收集器将DAO列表转换为 Map<String, List<Pojo>>

daoList看起来像这样：

[0] : id = "34234", team = "gools", name = "bob", type = "old"
[1] : id = "23423", team = "fool" , name = "sam", type = "new"
[2] : id = "34342", team = "gools" , name = "dan", type = "new"

我想对“团队”属性进行分组，并为每个团队提供一个列表，如下所示：

"gools":
       ["id": 34234, "name": "bob", "type": "old"],
       ["id": 34342, "name": "dan", "type": "new"]

"fool":
       ["id": 23423, "name": "sam", "type": "new"]

Pojo看起来像这样：

@Data
@NoArgsConstructor
@AllArgsConstructor(access = AccessLevel.PUBLIC)
public class Pojo{

    private String …

我正在为公司开发一个网站，并且使用Spring作为后端。现在有一种情况，我需要两次使用一种Utils方法，但是要使用不同的DAO。

为了避免代码重复，我想知道如何使用Java泛型来使该方法可用于两种情况。该方法仅计算两个DAO共有的字段之一。

使用方法：

SeverityCount calculateSeveritiesCount(List<?> events){

        if(null == events){
            return new SeverityCount();
        }

        if(events.get(1) instanceof EventDAO){
            events = (List<EventDAO>)events;
        }
        else if (events.get(1) instanceof EventsByAreaDAO) {
            events = (List<EventsByAreaDAO>)events;
        }

        Map<String, Long> severityCountMap = events.stream().collect(
            Collectors.groupingBy(
                EventDAO::getSeverity,  //It should be EventDAO or EventsByAreaDAO. both has severity field.
                Collectors.counting())
        );

        return mapper.convertValue(severityCountMap, SeverityCount.class);
    }

活动DAO：

@Data
@NoArgsConstructor
@AllArgsConstructor
@Entity
@Table(name = "events")
public class EventDAO {
    @Id @Column(name = "uid")
    private String uID;

    private String date;

    private String severity;

}

区域DAO： …

尝试从文件中过滤特定单词时,我遇到了一些问题,并将它们写入新文件.我想要做的只是写'&'之后的单词直到第一个数字.

例如(这是我正在阅读的文件的内容):

& some 12 test1 test2
$ thisword 4 no no no no

对于上面的输入,我想在一个新文件中写入some和thisword.

我的代码工作正常,但它不是只打印那些单词,而是打印垃圾.

int main (argc,argv)
     int argc;
     char *argv[];
{
    int inpfd,outpfd,n;
    int i=0;
    char tmp[2],buff[BUFFSIZE];    //This is our buffer

    //Open the output file of ispell
    inpfd = open("outputfile.txt",O_RDONLY);

    //Check if open command failed
    if(inpfd == -1) {
        printf("Failed to open file");
        exit(1);
    }

    //Here we are reading from output file
    read(inpfd,buff,999);
    buff[999] = '\0';
    close(inpfd);

    outpfd = open("w.txt",O_WRONLY);

    if(outpfd == -1) …