如何使用subDocumet访问subDocument的DBObject

Question

我需要从下面的json获得所有名称字段的列表。我试图通过映射一个DBObject来实现这一点。

杰森：

{
    "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"
                }
            ]
        }
    ] }

代码：

DBCollection collection = mongoTemplate.getCollection("testTag")； Map map =新HashMap()；DBObject obj =null；BasicDBObject查询=新BasicDBObject()；query.put("ThirdOne.explicitElements.name"，"myTag")；BasicDBObject字段=新BasicDBObject()；fields.put("ThirdOne.explicitElements.name"，1)；fields.put("ThirdOne.explicitElements.value"，1)；DBCursor cursor2 =DBCursor(查询，字段)；while (cursor2.hasNext()) { obj = cursor2.next()；map = obj.toMap()； 对于(Map.Entry条目: map.entrySet()) { System.out.println("Key：“+ entry.getKey() +”值：“+ entry.getValue())；}

结果：

键：_id值:523f910681a9535f8af5a91 键: ThirdOne值：[{ "explicitElements“：{”explicitElements“：{”explicitElements“：”mytag“，"value":"myrequest"}，{”explicitElements“：”booleantest“，”explicitElements“：”true“}}]

我只想

键："name“值："mytag” 键：“值”值：“我的请求”等等。

对于如何使用DBObjects实现这一点，有什么建议吗？

Answer 1

这里有一组值字段，存储在DBObject中，存储在DBList中，存储在DBObject中，存储在DBList中，存储在由DBCursor迭代的DBObjects中。由于这个复杂的文档结构，当您只想输出特定叶子上的文档时，您需要遍历整棵树。

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());
           }
     }
}