基于 Map Key Spring Repository 查询 MongoDb [英] Query MongoDb based on Map Key Spring Repository

问题描述

我需要帮助来查询嵌套文档.将 Spring Boot 与 MongoDB 结合使用.

结构:

公共课假期{@ID私人字符串ID；私人整数年；私有地图<字符串，列表>假期 = 新的 HashMap<>();}公共类假日元素{私人字符串名称；@JsonFormat(pattern="yyyy-MM-dd")私人日期；私人字符串笔记；}

保存 Json 的所有内容后:

<预><代码>[{"id": "5a153331b3cb1f0001e1edeb",年份":2017，假期":{BB":[{"name": "Neujahrstag","日期": "2017-01-01",笔记": ""},...],呵呵":[{ ... }]}]

现在我如何获得例如:状态为BB"的HolidayElement"列表?

解决方案

假设您有一个像 HolidayRepository 这样的存储库，您需要创建一个自定义实现，因为您想使用 MongoTemplate.所以你的 HolidayRepository 看起来像

@Repository公共接口 HolidayRepository 扩展 MongoRepository, HolidayRepositoryCustom {}

并声明两个新文件HolidayRepositoryCustom 和HolidayRepositoryImpl 与HolidayRepository 位于同一目录下(非常重要)

公共接口 HolidayRepositoryCustom {列表findByMapId(final String mapId);}

Impl 类看起来像这样

public class HolidayRepositoryImpl 实现 HolidayRepositoryCustom {私人最终 MongoTemplate mongoTemplate;@自动连线public HolidayRepositoryImpl(final MongoTemplate mongoTemplate) {this.mongoTemplate = mongoTemplate;}@覆盖公共列表findByMapId(String mapId) {最终 QueryBuilder queryBuilder = QueryBuilder.start();查询生成器.and("holidays."+mapId).exists(true);最终的 DBObject 投影 = new BasicDBObject();投影.put("假期."+mapId, 1);String collectionName = "Holiday";//改成你的收藏名尝试(最终 DBCursor dbCursor = mongoTemplate.getCollection(collectionName).find(queryBuilder.get(),projection)){如果(dbCursor.hasNext()){DBObject next = dbCursor.next();地图<字符串、列表>假期元素 =(Map>) next.get("holidays");返回holidayElements.get(mapId);}}返回 Lists.newArrayList();}}

I need help to query nested documents. Using Spring Boot with MongoDB.

Structure:

public class Holiday {
  @Id
  private String id;

  private Integer year;

  private Map<String, List<HolidayElement>>  holidays = new HashMap<>();
}

public class HolidayElement {

  private String name;

  @JsonFormat(pattern="yyyy-MM-dd")
  private Date date;

  private String note;
}

After saving everything the Json looks like:

[
   {
      "id": "5a153331b3cb1f0001e1edeb",
      "year": 2017,
      "holidays": {
         "BB": [
            {
                "name": "Neujahrstag",
                "date": "2017-01-01",
                "note": ""
            },
            ...
         ],
         "HH": [
             { ... }
         ]
    }
  ]

Now how can I get for instance: List of "HolidayElement" where the State is "BB"?

解决方案

Assuming you have a repository like HolidayRepository, you need to create a custom implementation since you want to use MongoTemplate. So your HolidayRepository will look like

@Repository
public interface HolidayRepository extends MongoRepository<Holiday, String>, HolidayRepositoryCustom {

} 

And declare two new files HolidayRepositoryCustom and HolidayRepositoryImpl in the same directory(very important) as HolidayRepository

public interface HolidayRepositoryCustom {

  List<HolidayElement> findByMapId(final String mapId);
}

And the Impl class will look like this

public class HolidayRepositoryImpl implements  HolidayRepositoryCustom {


  private final MongoTemplate mongoTemplate;

  @Autowired
  public HolidayRepositoryImpl(final MongoTemplate mongoTemplate) {
    this.mongoTemplate = mongoTemplate;
  }

  @Override
  public List<HolidayElement> findByMapId(String mapId) {

    final QueryBuilder queryBuilder = QueryBuilder.start();
    queryBuilder
        .and("holidays."+mapId).exists(true);

   final DBObject projection = new BasicDBObject();
   projection.put("holidays."+mapId, 1);

    String collectionName = "Holiday";//Change to your collection name
    try( final DBCursor dbCursor = mongoTemplate.getCollection(collectionName).find(queryBuilder.get(), projection)){
      if(dbCursor.hasNext()){
        DBObject next = dbCursor.next();
        Map<String, List<HolidayElement>> holidayElements = 
           (Map<String, List<HolidayElement>>) next.get("holidays");
        return holidayElements.get(mapId);
  }
    }
  return Lists.newArrayList();
  }
}

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