java - 如何从 rest api 序列化枚举列表

Question

我想从 rest api 调用返回枚举列表，并让它以 JSON 格式显示枚举的值而不仅仅是枚举名称。目前我的休息电话返回 json 看起来像:

{
  "responses": [
    "ACTION_TAKEN",
    "IGNORED",
    "UNDETECTED"
  ]
}

但是，我希望它更像(或类似这样的东西):

{
  "responses": [
    {
      "name":"ACTION_TAKEN",
      "value":"Action Taken"
    },
    {
      "name":"IGNORED",
      "value":"Ignored"
    },
    {
      "name":"UNDETECTED",
      "value":"Undetected"
    }
   ]
}

我的枚举看起来像:

public enum Response {

  ACTION_TAKEN ("Action Taken"),
  IGNORED ("Ignored"),
  UNDETECTED("Undetected");

  private String value;

  Response(String value) {
    this.value = value;
  }

  public String getValue() {
    return this.value;
  }

  @Override
  public String toString() {
    return value;
  }
}

我的模型对象看起来像这样。为了这个例子，它只有一个枚举值列表。

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class StaticData {

  private List<Response> responses;

  public List<Response> getResponses() {
    return responses;
  }

  public void setResponses(List<Response> responses) {
    this.responses = responses;
  }
}

Web 服务方法如下所示:

@Component
@Path("staticData")
@Produces("application/json")
@Consumes("application/json")
public class StaticDataResource {

  @GET
  public Response getCurrentContent() {
    StaticData staticData = new StaticData();
    staticData.setResponses(Arrays.asList(Response.values()));
    return Response.ok(staticData).build();
  }
}

这是我的有效 pom 的依赖项(抱歉格式错误)

<dependencies>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aspects</artifactId>
    <version>4.2.5.RELEASE</version>
    <scope>compile</scope>
  </dependency>
  <dependency>
    <groupId>com.sun.jersey.contribs</groupId>
    <artifactId>jersey-spring</artifactId>
    <version>1.19.1</version>
    <scope>compile</scope>
    <exclusions>
      <exclusion>
        <artifactId>*</artifactId>
        <groupId>org.springframework</groupId>
      </exclusion>
    </exclusions>
  </dependency>
  <dependency>
    <groupId>com.thetransactioncompany</groupId>
    <artifactId>cors-filter</artifactId>
    <version>2.4</version>
    <scope>compile</scope>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
    <version>4.2.5.RELEASE</version>
    <scope>compile</scope>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>4.2.5.RELEASE</version>
    <scope>compile</scope>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-expression</artifactId>
    <version>4.2.5.RELEASE</version>
    <scope>compile</scope>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-oxm</artifactId>
    <version>4.2.5.RELEASE</version>
    <scope>compile</scope>
  </dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-orm</artifactId>
  <version>4.2.5.RELEASE</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-api</artifactId>
  <version>1.7.19</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-log4j12</artifactId>
  <version>1.7.19</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>commons-logging</groupId>
  <artifactId>commons-logging</artifactId>
  <version>1.2</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>commons-io</groupId>
  <artifactId>commons-io</artifactId>
  <version>2.4</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>com.google.guava</groupId>
  <artifactId>guava</artifactId>
  <version>19.0</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.reflections</groupId>
  <artifactId>reflections</artifactId>
  <version>0.9.10</version>
  <scope>compile</scope>
  <exclusions>
    <exclusion>
      <artifactId>guava</artifactId>
      <groupId>com.google.guava</groupId>
    </exclusion>
  </exclusions>
</dependency>
<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>javax.servlet-api</artifactId>
  <version>3.0.1</version>
  <scope>provided</scope>
</dependency>
<dependency>
  <groupId>javax.ws.rs</groupId>
  <artifactId>javax.ws.rs-api</artifactId>
  <version>2.0.1</version>
  <scope>provided</scope>
</dependency>
<dependency>
  <groupId>org.eclipse.persistence</groupId>
  <artifactId>javax.persistence</artifactId>
  <version>2.1.0</version>
  <scope>provided</scope>
</dependency>
<dependency>
  <groupId>javax.ejb</groupId>
  <artifactId>javax.ejb-api</artifactId>
  <version>3.2</version>
  <scope>provided</scope>
</dependency>
  <dependency>
      <groupId>javax.transaction</groupId>
      <artifactId>jta</artifactId>
      <version>1.1</version>
      <scope>provided</scope>
    </dependency>
</dependencies>

我试过添加 @JsonFormat(shape = JsonFormat.Shape.Object)到我的枚举类的顶部。它没有用。我尝试添加 @JsonValue到枚举类中我的 getValue() 方法之上，但这也不起作用。我尝试添加一个扩展 StdSerializer 或 JsonSerializer 的自定义序列化程序，并使用 @JsonSerialize(using = ReasonSerializer) 在我的枚举上方引用该类.我在 serialize 方法中放置了一个断点并且没有命中它，所以那没有用。我稍微看了看做implements ContextResolver<ObjectMapper> ，但无法完全弄清楚，或者这是否是正确的路径。

非常感谢任何帮助!谢谢!

Answer 1

最终解决方案

这适用于 JAX-RS，我已经用您的代码对其进行了测试。

将 @JsonFormat 与 public String getName() 一起使用。

@JsonFormat(shape=JsonFormat.Shape.OBJECT)
public enum Response {
    ACTION_TAKEN ("Action Taken"),
    IGNORED ("Ignored"),
    UNDETECTED("Undetected");

    private String value;

    Response(String value) {
        this.value = value;
    }
    // Getters, Setters

    public String getName() {
        return name();
    }
}

JSON 输出

{
    "responses": [{
            "value": "Action Taken",
            "name": "ACTION_TAKEN"
        }, {
            "value": "Ignored",
            "name": "IGNORED"
        }, {
            "value": "Undetected",
            "name": "UNDETECTED"
        }
    ]
}

使用以下依赖项进行测试。

import com.fasterxml.jackson.annotation.JsonFormat;

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>2.9.6</version>
</dependency>

替代方案

Jackson 文档指出，行为可能会根据使用的序列化程序而改变。因此，如果第一个解决方案不起作用，那么这个解决方案可能会奏效。

@JsonFormat(shape=JsonFormat.Shape.OBJECT)
public enum Response {
    ACTION_TAKEN ("Action Taken"),
    IGNORED ("Ignored"),
    UNDETECTED("Undetected");

    private String name;
    private String value;

    Response(String value) {
        name = name();
        this.value = value;
    }
    
    public String getName() {
        return name;
    }
    
    public String getValue() {
        return value;
    }
}