如果属性名称不等于字段名称，Jackson @JsonProperty 不起作用 [英] Jackson @JsonProperty not working if property name not equal field name

问题描述

我有以下 JSON

{
  "known-name": "Zevs",
  "approximate-age": 320
}

和绑定类

public class GodBinding {

  @JsonProperty("known-name")
  public String name;

  @JsonProperty("approximate-age")
  public int age;

  // constructors
  // getters & setters
}

并遵循 maven 依赖项2.23.22.5.4

And followng maven dependencies 2.23.2 2.5.4

 <dependencies>
    <dependency>
        <groupId>org.glassfish.jersey.containers</groupId>
        <artifactId>jersey-container-servlet</artifactId>
        <version>${jersey.version}</version>
        <scope>provided</scope>
    </dependency>

    <dependency>
        <groupId>com.fasterxml.jackson.jaxrs</groupId>
        <artifactId>jackson-jaxrs-json-provider</artifactId>
        <version>${jackson.version}</version>
    </dependency>
 </dependencies>

如果我发布这样的json，那么我会得到意想不到的结果，结果为空.

If I post such json then I have unexpected result with null's.

GodBinding [name=null, age=0]

如果我使用没有名称的@JsonProperty 并发送 JSON，其中属性名称等于字段名称

If I use @JsonProperty without names and send JSON where property names equal field names

{
  "name": "Zevs",
  "age": 320
}

然后它工作正常

GodBinding [name=Zevs, age=320]

如果有人知道，如何使字段上的@JsonProperty("name") 正常工作?

If somebody know, how to make @JsonProperty("name") on fields working correctly?

推荐答案

当Jackson 的注解是Jackson 1，而你想使用Jackson 2 时，经常会出现这种情况，很多其他问题都提到过.

This is often caused when the annotations of Jackson is of Jackson 1, but you want to use Jackson 2, as mentioned in many other questions.

就我而言，在项目中我有另一个错误导入的依赖项:

In my case, in the project I have another dependency which was imported wrongly:

import org.testcontainers.shaded.com.fasterxml.jackson.databind.ObjectMapper;

当我创建 ObjectMapper 时.我猜 testcontainers 使用它自己的 ObjectMapper 作为它的依赖并错误地暴露它；实际上它是一个旧版本.不确定哪个是.

when I create the ObjectMapper. I guess testcontainers uses its own ObjectMapper as its dependency and exposed it incorrectly; actually it is an older version. Not sure which is.

我改成

import com.fasterxml.jackson.databind.ObjectMapper;

现在一切正常.这就是我所说的第一级依赖"，而不是依赖的依赖".在我的 gradle 文件中，它是 2.3 版.

and all works now. This is what I call "first level dependency", not "dependency of dependency". In my gradle file it is version 2.3.

我提到这个是因为:

• 我看到其他问题只提到了 Jackson 1 和 2 之间的混淆，而不是 testcontainer 的这个.我们必须忽略那些不是 fasterxml.jackson 的.

• I see other questions only mentioning the confusion between Jackson 1 and 2, not this of testcontainer. We just must ignore those not of fasterxml.jackson.

不仅要注意@JsonProperty等的版本，还要注意你在导入ObjectMapper和反序列化功能.

Pay attention of the version not only of @JsonProperty, etc, but also the version of Jackson you use when importing ObjectMapper and DeserializationFeature.

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