使用Spring和Jackson JSON将java.io.Serializable实例序列化为JSON [英] Serializing java.io.Serializable instance into JSON with Spring and Jackson JSON

问题描述

我从一些内部API中获取 Serializable 的实例。 Serializable 实例实际上是 Long 或 String 等。有没有办法让DTO能够处理这种情况？使用私有可序列化值; JSON以值结束：{} 。

I am getting an instance of Serializable out of some internal APIs. The Serializable instance is actually Long or String, etc. Is there a way to make a DTO that can handle this situation? Using private Serializable value; the JSON ends up with value: {}.

更新

以下是相关代码的简化示例：

Here is a reduced example of the code in question:

@Controller
public class SomeController
{
  //...
  public MyDto getInfo(Long id)
  {
    MyDto result = new MyDto();
    Serializable obj = svc.getInfo(id);
    // obj is either Long, or String, or one of few more fundamental Java types
    result.setValue(obj);
    return result;
  }
}

public class MyDto
{
  private Serializable value;
  public void setValue(Serializable info)
  {
    this.value = value;
  }
  public Serializable getValue()
  {
    return value;
  }
}

更新2

我在这里找到了问题的答案： https://stackoverflow.com / a / 20494813/341065

I have found the answer to my problem here: https://stackoverflow.com/a/20494813/341065

推荐答案

请注意，Jackson不使用 java.io .Serializable 任何东西：添加它没有实际价值。它会被忽略。

Note that Jackson does not use java.io.Serializable for anything: there is no real value for adding that. It gets ignored.

鉴于此，杰克逊将看到的值等同于任何实际类型（对于序列化，即编写JSON）;或者，当读取时，相当于 java.lang.Object 。

Given this, Jackson will see values as equivalent of whatever actual type is (for serialization, i.e. writing JSON); or, when reading, as equivalent of java.lang.Object.

如果您知道实际类型，那么可以使用 @JsonDeserialize（as = ActualType.class）注释属性以提供提示。但是如果实际值是 String s和 Long s，那么确实不需要这样做。

If you know the actual type, you could annotate property with @JsonDeserialize(as=ActualType.class) to give a hint. But if actual values are Strings and Longs, this really should not be needed.

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