java - 找不到非具体 Map 类型的反序列化器 [map type;类 javax.ws.rs.core.MultivaluedMap

Question

我在使用 org.codehaus.jackson.map.ObjectMapper 进行反序列化时遇到以下问题，该问题不适用于以下类。我不确定我正在使用的 MultivaluedMap 出了什么问题。

 public class ClassD
 {
    private ClassA objA;
    private ClassB objB;
    private final ClassC objC;
    private MultivaluedMap<String, String> headerMap;
 }

public static void main(String[] args) {
    String fileName = "someFilePath";
    mockCollection = fromJSON(new TypeReference<Collection<ClassD>>() {}, new String(Files.readAllBytes(Paths.get(fileName)), StandardCharsets.UTF_8));
}

public static <T> T fromJSON(final TypeReference<T> type, final String jsonPacket) throws JsonParseException, JsonMappingException, IOException {
       T data = null;
       ObjectMapper om = new ObjectMapper();
       om.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);
       data = om.readValue(jsonPacket, type);
       return data;
    }


Exception : 
org.codehaus.jackson.map.JsonMappingException: Can not find a deserializer for non-concrete Map type [map type; class javax.ws.rs.core.MultivaluedMap, [simple type, class java.lang.String] -> [collection type; class java.util.List, contains [simple type, class java.lang.String]]]
    at org.codehaus.jackson.map.deser.StdDeserializerProvider._createAndCache2(StdDeserializerProvider.java:315)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider._createAndCacheValueDeserializer(StdDeserializerProvider.java:290)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider.findValueDeserializer(StdDeserializerProvider.java:159)
    at org.codehaus.jackson.map.deser.std.StdDeserializer.findDeserializer(StdDeserializer.java:620)
    at org.codehaus.jackson.map.deser.BeanDeserializer.resolve(BeanDeserializer.java:379)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider._resolveDeserializer(StdDeserializerProvider.java:407)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider._createAndCache2(StdDeserializerProvider.java:352)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider._createAndCacheValueDeserializer(StdDeserializerProvider.java:290)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider.findValueDeserializer(StdDeserializerProvider.java:159)
    at org.codehaus.jackson.map.deser.BasicDeserializerFactory.createCollectionDeserializer(BasicDeserializerFactory.java:284)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider._createDeserializer(StdDeserializerProvider.java:389)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider._createAndCache2(StdDeserializerProvider.java:310)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider._createAndCacheValueDeserializer(StdDeserializerProvider.java:290)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider.findValueDeserializer(StdDeserializerProvider.java:159)
    at org.codehaus.jackson.map.deser.StdDeserializerProvider.findTypedValueDeserializer(StdDeserializerProvider.java:180)
    at org.codehaus.jackson.map.ObjectMapper._findRootDeserializer(ObjectMapper.java:2829)
    at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2728)
    at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1870)

Answer 1

在人们面临同样的问题时发布答案。您可以使用此实用程序来解决您的问题

public static <T> T deserializeJson(final String json, final Class<T> clazz) throws JsonParseException, JsonMappingException, IOException {
    ObjectMapper om = new ObjectMapper();
    om.setVisibility(JsonMethod.FIELD, Visibility.ANY);
    om.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    return om.readValue(json, clazz);
}

public static <T> String serializeToJson(final T object) throws JsonGenerationException, JsonMappingException, IOException {
    ObjectMapper om = new ObjectMapper();
    om.setVisibility(JsonMethod.FIELD, Visibility.ANY);
    return om.writeValueAsString(object);
}