无法通过Jackson Yaml反序列化对象数组

Question

我试图反序列化一个YAML配置文件，它将一个特定的操作(enum)映射到参数(String[])。为了为YAML提供一个起点，我首先用Java构建了对象结构，然后对其进行序列化。

读取输出并反序列化它也会导致下面的异常，这是意外的，因为这是直接从马嘴里出来的。

我的Java结构：

@NoArgsConstructor
@AllArgsConstructor
@ToString(doNotUseGetters = true)
@Data
public class Session {
  @EqualsAndHashCode.Exclude protected List<ActionInstance> actions;
}

@NoArgsConstructor
@AllArgsConstructor
@ToString(doNotUseGetters = true)
@Data
public class ActionInstance {
  protected Action action;
  protected String[] arguments;
}

public enum Action {
  Left,
  Right,
  Up,
  Down;
}

YAML (直接取自Jackson的序列化输出，将其读取回引起下面的异常)：

actions: !<java.util.ImmutableCollections$List12>
- !<java.util.ImmutableCollections$List12>
  arguments:
  - 90.00
  action: Left

杰克逊服务反序列化：

objectMapper.readValue(inputStream, Session.class)

例外：

com.fasterxml.jackson.databind.exc.MismatchedInputException
Unexpected token (VALUE_STRING), expected START_ARRAY: need JSON Array to contain As.WRAPPER_ARRAY type information for class Action

编辑#1：

final Session export = new Session();
        export.setActions(
            List.of(
                new ActionInstance(Action.Left, new String[] {"90.00"})));
        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
        serializationService.serialize(export, baos);

杰克逊的实现大致是这样的：

outputStream.write(objectMapper.writeValueAsBytes(data));

ObjectMapperProvider：

public class ObjectMapperProvider implements Provider<ObjectMapper> {
  protected final ObjectMapper objectMapper = new ObjectMapper(new YAMLFactory());
  protected final JavaTimeModule javaTimeModule = new JavaTimeModule();

  @Inject
  public ObjectMapperProvider() {
    // Hack time module to allow 'Z' at the end of string (i.e. javascript json's)
    javaTimeModule.addDeserializer(
        LocalDateTime.class, new LocalDateTimeDeserializer(DateTimeFormatter.ISO_DATE_TIME));
    objectMapper.registerModule(javaTimeModule);
    objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);

    objectMapper.activateDefaultTyping(objectMapper.getPolymorphicTypeValidator());

Answer 1

解决办法很简单：

行动：!

• 参数：
  • 90.00动作：!