如何过滤嵌套的 JSON 值？

Question

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;
    }

Answer 1

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 (eg 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);

Answer 2

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

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