NullPoInterException试图读取JSON并尝试将其转换为POJO（避免）

Question

我们的目标是：解析JSON文件并将其划分为Java Pojo，

stacktrace看起来像这样：

16:39:21,628 ERROR [stderr] (default task-1) java.lang.NullPointerException
16:39:21,628 ERROR [stderr] (default task-1)    at deployment.webservice_child.war //ProfileDeserializer.deserialize(ProfileDeserializer.java:31)
16:39:21,628 ERROR [stderr] (default task-1)    at deployment.webservice_child.war //ProfileDeserializer.deserialize(ProfileDeserializer.java:16)

我们试图解析的文件看起来像这样：

{
  "properties": {
    "anon": {
      "/brief/versicherungsnehmer/vorname": true,
      "/brief/versicherungsnehmer/nachname": true
    }
  }
}

我们的JSON Parser类称为jsonmuncher看起来像这样：

public class JSONMuncher {

    private final ObjectMapper objectMapper;

    public JSONMuncher() {
        this.objectMapper = createObjectMapper();
    }

    public ObjectMapper getObjectMapper() {
        return objectMapper;
    }

    private static ObjectMapper createObjectMapper() {
        SimpleModule module = new SimpleModule()
                .addSerializer(Properties.class, new ProfileSerializer())
                .addDeserializer(Properties.class, new ProfileDeserializer());

        return new ObjectMapper(new JsonFactory()
                .disable(JsonGenerator.Feature.AUTO_CLOSE_JSON_CONTENT))
                .registerModule(module);
    }
    public Object readConfig(String filepath) {
        try {
            ObjectMapper mapper = createObjectMapper();
            SimpleModule module = new SimpleModule();
            mapper.configure(Feature.AUTO_CLOSE_SOURCE, true);
            mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
            // do not serialize null value fields
            mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
            mapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);
            module.addSerializer(Properties.class, new ProfileSerializer());
            module.addDeserializer(Properties.class, new ProfileDeserializer());
            mapper.registerModule(module);

            InputStream is = new FileInputStream(filepath);
            System.out.println("[DEBUG!!!!!!!!!111!!!]: " + is.read());
            Properties anon = mapper.readValue(is, Properties.class);
            
            System.out.println(anon.getVorname());
            System.out.println(anon.getNachname());

            return anon;
        } catch (IOException e) {
            System.out.println("Beep Boop Err!!! 
              

Answer 1

好的，所以我能够通过像这样修改我的deSerialize（）函数来解决此问题并获得正确的值：

@Override
    public Properties deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
       JsonNode profileNode = 
          jsonParser.getCodec().readTree(jsonParser);
       Properties property = new Properties();
        
   System.out.println(profileNode.get("properties").get("anon").get("/brief/versicherungsnehmer/vorname").booleanValue());
        property.setVorname(profileNode.get("properties").get("anon").get("/brief/versicherungsnehmer/vorname").booleanValue());

 System.out.println(profileNode.get("properties").get("anon").get("/brief/versicherungsnehmer/nachname").booleanValue());
        property.setNachname(profileNode.get("properties").get("anon").get("/brief/versicherungsnehmer/nachname").booleanValue());

return property;

}