Question

我需要从以下json获取所有名称字段的列表。我试图通过映射DBObject来做到这一点。

JSON：

{
    "firstOne": [
        {
            "file": "FileA",
            "Data": "One",
            "version": "0.4"
        }
    ],
    "secondOne": [
        {
            "elementName": "version",
            "complexElement": "true",
            "elementDataType": ""
        }
    ],
    "ThirdOne": [
        {
            "elementName": "version",
            "explicitElements": [
                {
                    "name": "mytag",
                    "type": "String",
                    "value": "myrequest"
                },
                {
                    "name": "booleantest",
                    "type": "Boolean",
                    "value": "true"
                }
            ]
        }
    ] }

CODE：

DBCollection collection = mongoTemplate.getCollection（“testTag”）;

  Map<DBObject, DBObject> map = new HashMap<DBObject, DBObject>();
  DBObject obj =null;

  BasicDBObject query = new BasicDBObject();
  query.put("ThirdOne.explicitElements.name", "myTag");
  BasicDBObject fields = new BasicDBObject();
  fields.put("ThirdOne.explicitElements.name", 1);
  fields.put("ThirdOne.explicitElements.value", 1);

  DBCursor cursor2 = collection.find(query, fields);      while

（cursor2.hasNext（））{obj = cursor2.next（）; map = obj.toMap（）;

      for (Map.Entry<DBObject, DBObject> entry : map.entrySet()) {
          System.out.println("Key : " + entry.getKey() + " Value : "
                  + entry.getValue());


      }
              }

结果：

键：_id值：523f910681a9535f8af5aa91

Key：ThirdOne Value：[{“explicitElements”：[{“name”：“mytag”，   “value”：“myrequest”}，{“name”：“booleantest”，“value”：“true”}]}]

我想只获得

key：“name”value：“mytag”

key：“value”value：“myrequest”等......

有关如何使用DBObjects执行此操作的任何建议吗？

Answer 1

这里有一堆存储在DBObject存储在DBList存储在DBObject中的DBList的值字段，存储在DBObject存储在DBCursor中的while (cursor2.hasNext()) { // you are now iterating a list objects with three Fields: // FirstOne, SecondOne and ThirdOne. You only want ThirdOne obj = cursor2.next(); map = obj.toMap(); DBList thirdOne = (DBList)map.get("ThirdOne"); // now we iterat the list in ThirdOne for (Object o: thirdOne) { DBObject thirdOneEntry = (DBObject)o; // we get the explicitElements-array from each entry DBList explicitElements = (DBList)thirdOneEntry.get("explicitElements"); // now we iterate the expliciteElements for (Object o: explicitElements) { DBObject explicitElementsEntry = (DBObject)o; // and write them Object key = explicitElementsEntry.get("key"); Object value = explicitElementsEntry.get("value"); System.out.println("Key : " + key.toString() + " Value : " value.toString()); } } }存储在{{1}}中1}}由{{1}}迭代。由于这种复杂的文档结构，当您只想输出特定叶子上的那些时，您需要遍历整个树。

{{1}}

如何使用DBObject访问subDocument的subDocumet

1 个答案: