如何使用 Java 從 Json 字符串中提取 Json 值？

Question

This is my json structure and I want to get the values of hierarchy_name from each json object in an Array, can someone help me with that using Java..

  {
 "hits": {
  "total": {
   "value": 218
  },
  "max_score": null,
  "hits": [
   {
    "_index": "planlytx",
    "_source": {
     "hierarchy_name": "PRODUCT"
    },
    "fields": {
     "attribute_name.keyword": [
      "PRODUCT"
     ]
    }
   },
   {
    "_index": "planlytx",
    "_source": {
     "hierarchy_name": "PRODUCT"
    },
    "fields": {
     "attribute_name.keyword": [
      "PRODUCT-ALL"
     ]
    }
   }
  ]
 }
}

Answer 1

使用org.json ，您可以執行以下操作：

JSONArray hitsArray = new JSONObject(jsonStr).getJSONObject("hits").getJSONArray("hits");

List<String> keywords = IntStream.range(0, hitsArray.length())
        .mapToObj(hitsArray::getJSONObject)
        .map(json -> json.getJSONObject("fields")
                .getJSONArray("attribute_name.keyword")
                .toList())
        .flatMap(objects -> objects.stream().map(Object::toString))
        .collect(Collectors.toList());

對於“hierarchy_name”：

JSONArray hitsArray = new JSONObject(jsonStr).getJSONObject("hits").getJSONArray("hits");

List<String> keywords = IntStream.range(0, hitsArray.length())
        .mapToObj(hitsArray::getJSONObject)
        .map(json -> json.getJSONObject("_source").getString("hierarchy_name"))
        .collect(Collectors.toList());

Output：

[PRODUCT, PRODUCT-ALL]