CODEWITHSUNDEEP
javacollectionsjava-8jacksonjava-stream
Faramarz Afzali
Faramarz Afzali

Reputation: 795

How to filter nested JSON values?

I have a JSON file like below. I want to read all the values and check if the input string contains one of the JSON values, the return true. But with my try, always it returns false.

{
  "RECORDS": [
    {
      "word": "word1",
      "language": "en"
    },
    {
      "word": "word2",
      "language": "en"
    },
    {
      "word": "word3",
      "language": "en"
    }
  ]
}

My method


 public static boolean check(String content) throws IOException {
        File file = ResourceUtils.getFile("classpath:sample.json");

        ObjectMapper mapper = new ObjectMapper();
        Map<?, ?> map = mapper.readValue(file, Map.class);
        for (Map.Entry<?, ?> entry : map.entrySet()) {
            if (content.contains(entry.getValue().toString())) {
                return true;
            } else
                return false;
        }

        return false;
    }

Upvotes: 1

Views: 2150

Answers (2)

ETO
ETO

Reputation: 7269

Try this:

return mapper.readValue(file, new TypeReference<Map<String, List<Map<String, String>>>>() {})
             .values()
             .stream()
             .flatMap(List::stream)
             .map(Map::values)
             .flatMap(Collection::stream)
             .anyMatch(content::contains);

The code snippet above will check whether your content string contains any of the nested values (e.g. word1, en, word2 ...)

If you're looking for values of the word field only, then try the following:

return mapper.readValue("", new TypeReference<Map<String, List<Map<String, String>>>>() {})
             .values()
             .stream()
             .flatMap(List::stream)
             .map(m -> m.get("word"))
             .anyMatch(content::contains);

Upvotes: 1

Hasham Rasheed
Hasham Rasheed

Reputation: 59

for (Map.Entry<?, ?> entry : map.entrySet()) will get you a LinkedHashMap Entry. So basically, your entry variable will look something like this:

enter image description here

for your code to work, you will need to iterate over the values again before doing the contains check

Upvotes: 0

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