如何将传入的 AWS Lambda 请求反序列化为 lombok @Value 或 @Data 类？

发布于 2025-01-10 21:53:54 字数 607 浏览 0 评论 0原文

如果我有一个

import lombok.Value;

@Value
public class IncomingRequest {
    String data;
}

并尝试拥有一个 RequestHandler ，就像

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;

public class LambdaHandler implements RequestHandler<IncomingRequest, String> {

    @Override
    public String handleRequest(IncomingRequest request, Context context) {
        ...
    }
}

我只得到空的 request 对象或使用其他一些配置一样，我会得到反序列化异常。

我需要做什么才能使 AWS Lambda 正确反序列化到我的自定义类中？

原文

If I have a

import lombok.Value;

@Value
public class IncomingRequest {
    String data;
}

and try to have a RequestHandler like

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;

public class LambdaHandler implements RequestHandler<IncomingRequest, String> {

    @Override
    public String handleRequest(IncomingRequest request, Context context) {
        ...
    }
}

I only ever get empty request objects or with some other configuration I get deserialization exceptions.

What do I need to do to enable AWS Lambda to properly deserialize into my custom class?

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一束光，穿透我孤独的魂 2025-01-17 21:53:54

AWS Lambda 使用 Jackson 反序列化数据，因此需要一个无参数构造函数和属性设置器。您可以将这些设置器公开，但此时您有一个可变类，并且您通常不希望将其用于纯数据类。 “幸运的是”杰克逊无论如何都使用反射，因此可以（并且确实）访问私有方法。因此，您可以使用 @Value 而不是 @Value

import lombok.AccessLevel;
import lombok.Getter;
import lombok.Setter;

@Getter
@Setter(AccessLevel.PRIVATE)
public class IncomingRequest {
    String data;
}

这样，Jackson 就可以正确解析传入的 JSON，并且您的类仍然是不可变的。显然，如果您愿意，只要确保无参数构造函数仍然存在，您就可以通过注释向该类添加更多构造函数。如果您愿意，您也可以安全地添加 @ToString @EqualsAndHashCode 。

AWS Lambda uses Jackson to deserialize the data and as such needs a no-arg constructor and setters for the properties. You could make those setters public but at that point you have a mutable class and you generally do not want that for pure data classes. "Luckily" Jackson uses reflection anyway and therefore can (and does) access private methods. Instead of @Value you can therefore use

import lombok.AccessLevel;
import lombok.Getter;
import lombok.Setter;

@Getter
@Setter(AccessLevel.PRIVATE)
public class IncomingRequest {
    String data;
}

That way Jackson can properly parse the incoming JSON and your class remains sort-of immutable. Obviously you can add more constructors via annotation to that class if you want to as long as you make sure a no-args constructor is also still present. Add you can safely add @ToString @EqualsAndHashCode as well if you want to.

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