java - 使用 Jackson 将 map 序列化为 json 而不在输出中显示 map 名称

Question

我需要为休息服务显示以下类型的 Json 响应:

{
    "Server up": false,
    "database running": true,
    "dependency 1 up": true
}

为此，我定义了具有映射字段的 Java 对象 HealthCheckResponse.java。

public class HealthCheckResponse {
    @JsonProperty
    private Map<String, Boolean> statusMap;

    public Map<String, Boolean> getStatusMap() {
        return statusMap;
    }
    public void setStatusMap(Map<String, Boolean> statusMap) {
        statusMap = statusMap;
    }}

但是当我打印最终响应时， map 字段的名称也会出现在其中。

{
   "statusMap":
   {
       "Server up": false,
"database running": true,
"dependency 1 up": true
   }
}

请建议我需要在 HealthCheckResponse.java 中进行哪些更改，以摆脱输出显示中的“statusMap”和多余的花括号。这是我正在使用的对象映射器:

public class CustomObjectMapper extends ObjectMapper {

    public CustomObjectMapper() {
        super();

        configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        setVisibilityChecker(getSerializationConfig().getDefaultVisibilityChecker().withFieldVisibility(JsonAutoDetect.Visibility.NONE)
.withGetterVisibility(JsonAutoDetect.Visibility.NONE).withSetterVisibility(JsonAutoDetect.Visibility.NONE)
.withCreatorVisibility(JsonAutoDetect.Visibility.NONE).withIsGetterVisibility(JsonAutoDetect.Visibility.NONE));

        setSerializationInclusion(Include.NON_NULL);

        registerModule(new StringModule());
        registerModule(new GuavaModule());
    }
}

Answer 1

我相信 @JsonValue 在这里可以提供帮助。如果您更改对以下内容的回复:

public class HealthCheckResponse {
    private Map<String, Boolean> statusMap;

    @JsonValue
    public Map<String, Boolean> getStatusMap() {
        return statusMap;
    }

    public void setStatusMap(Map<String, Boolean> statusMap) {
        this.statusMap = statusMap;
    }
}

// The mapper can be used like this
final ObjectMapper mapper = new ObjectMapper();

// The POJO
final HealthCheckResponse healthCheckResponse = new HealthCheckResponse();
final Map<String, Boolean> statusMap = new HashMap<>();
statusMap.put("Server up", false);
statusMap.put("database running", true);
statusMap.put("dependency 1 up", true);
healthCheckResponse.setStatusMap(statusMap);

System.out.println(mapper.writeValueAsString(healthCheckResponse));

并且，输出将是:

{"Server up":false,"database running":true,"dependency 1 up":true}