另一个模块中的java AWS Lambda序列化对象

Question

我正在接受一些遗留代码，并试图编写一个lambda来处理函数

函数看起来像

public Task doTask(Message message) throws Exception {
   LOG.debug("debug message");
   // ... more code
}

但是，参数Message是在不同的模块中定义的（使用getter和setter）（并作为依赖项传入）。因此，我得到了一个错误：

{
  "errorMessage": "An error occurred during JSON parsing",
  "errorType": "java.lang.RuntimeException",
  "stackTrace": [],
  "cause": {
    "errorMessage": "com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of com.mywebsite.messaging.Message, problem: abstract types either need to be mapped to concrete types, have custom deserializer, or be instantiated with additional type information\n at [Source: lambdainternal.util.NativeMemoryAsInputStream@31610302; line: 1, column: 1]",
    "errorType": "java.io.UncheckedIOException",
    "stackTrace": [],
    "cause": {
      "errorMessage": "Can not construct instance of com.mywebsite.messaging.Message, problem: abstract types either need to be mapped to concrete types, have custom deserializer, or be instantiated with additional type information\n at [Source: lambdainternal.util.NativeMemoryAsInputStream@31610302; line: 1, column: 1]",
      "errorType": "com.fasterxml.jackson.databind.JsonMappingException",
      "stackTrace": [
        "com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:148)",
        "com.fasterxml.jackson.databind.DeserializationContext.instantiationException(DeserializationContext.java:892)",
        "com.fasterxml.jackson.databind.deser.AbstractDeserializer.deserialize(AbstractDeserializer.java:139)",
        "com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:1511)",
        "com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1102)"
      ]
    }
  }
}

如何序列化这个甚至不在我的模块中的对象

我们将非常感谢您的任何帮助

谢谢

Answer 1

看起来像com。我的网站。信息。消息是抽象类/ 界面在这种情况下：使用@JsonDeserialize将解决问题

大概是这样的：

@JsonDeserialize(using = MessageDeserializer.class)
interface Message {
}

@JsonDeserialize(as = MessageImpl.class)
public class MessageImpl implements Message{
//write your implementation
}   

public class MessageDeserializer extends JsonDeserializer<Message> {

    @Override
    public Message deserialize(JsonParser jp, DeserializationContext context) throws IOException {
        ObjectMapper mapper = (ObjectMapper) jp.getCodec();
        ObjectNode root = mapper.readTree(jp);
        return mapper.readValue(root.toString(), MessageImpl.class);
    }
}

这些链接可以帮助您： How to add custom deserializer to interface using jackson http://www.baeldung.com/jackson-exception

希望这有帮助