swagger JSON 文件上的空值

我在处理通过 Java 注释生成的 JSON swagger 文档时遇到了一些问题（REST 使用 Jersey 公开，序列化由 Jackson 处理）。查看生成的Swagger，它包括null值，这会导致 swagger UI 崩溃（生成的 YAML 不存在此问题）。

以下是 JSON 的摘录：

{
  "swagger": "2.0",
  "info": { "description": null, "version": "1.0.0", "title": "", "termsOfService": null, "contact": null, "license": null },
  "host": "localhost:8080",
  "basePath": "/api",
  "tags": [ { "name": "dataset", "description": null, "externalDocs": null } ],
  "schemes": [ "http" ],
  "consumes": null,
  "produces": null,
  "paths": {
    "/dataset": {
      "get": {
        "tags": ["dataset"],
        "summary": "A dataset",
        "description": "All the available datasets",
        "operationId": "datasetGet",
        "schemes": null,
        "consumes": null,
        "produces": ["application/json"],
        "parameters": [],
        "responses": {
          "200": {
            "description": "Available datasets",
            "schema": {
              "type": "object",
              "format": null,
              "example": null,
              "xml": null,
              "position": null,
              "description": null,
              "title": null,
              "readOnly": null,
              "additionalProperties": {
                "type": "object",
                "format": null,
                "example": null,
                "xml": null,
                "position": null,
                "description": null,
                "title": null,
                "readOnly": null,
                "additionalProperties": {
                  "type": "object",
                  "format": null,
                  "example": null,
                  "xml": null,
                  "position": null,
                  "description": null,
                  "title": null,
                  "readOnly": null,
                  "properties": null
                }
              }
            },
            "examples": null,
            "headers": null
          }
        },
        "security": null,
        "externalDocs": null,
        "deprecated": null
      },
      "head": null,
      "post": null,
      "put": null,
      "delete": null,
      "options": null,
      "patch": null,
      "parameters": null
    }
  },
  "parameters": null,
  "responses": null,
  "externalDocs": null,
  "securityRequirement": null
}

这个解决方案 https://stackoverflow.com/questions/11757487/how-to-tell-jackson-to-ignore-a-field-during-serialization-if-its-value-is-null建议设置对象映射器以省略null解决问题的价值，但现实是我不知道在哪里或如何轻松访问映射器，并使用NON_NULLREST 服务类上的注释毫无意义。类似的问题已被询问 https://stackoverflow.com/questions/33227114/swagger-json-produces-null-value-it-stops-ui以及，但我不使用Spring（所以我没有地方设置自定义映射器或设置）。

我过去使用过Swagger，但使用了不同的配置设置（与wink结合，现在我使用Jersey）并且没有这个问题。

如果有一些明显的配置错误，这是我的web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    version="3.0">

    <display-name>MyProject</display-name>

    <!-- Rest services mapping -->
    <servlet>
        <servlet-name>jersey</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
        <param-name>jersey.config.server.provider.classnames</param-name>
        <param-value>
            io.swagger.jersey.listing.ApiListingResourceJSON,
            org.something.DatasetApi
        </param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>jersey</servlet-name>
        <url-pattern>/service/*</url-pattern>
    </servlet-mapping>

    <!-- Swagger config class -->
    <servlet>
        <servlet-name>DefaultJaxrsConfig</servlet-name>
        <servlet-class>io.swagger.jaxrs.config.DefaultJaxrsConfig</servlet-class>
        <init-param>
            <param-name>api.version</param-name>
            <param-value>1.0.0</param-value>
        </init-param>
        <init-param>
            <param-name>swagger.api.basepath</param-name>
            <param-value>http://localhost:8080/api</param-value>
        </init-param>
        <load-on-startup>2</load-on-startup>
    </servlet>

    <!-- Just the CORS filter -->
    <filter>
        <filter-name>ApiOriginFilter</filter-name>
        <filter-class>org.something.ApiOriginFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>ApiOriginFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>

这是我的 pom.xml （我总是对 swagger 依赖项感到困惑）：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

    <groupId>org.something</groupId>
    <artifactId>my_project</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <modelVersion>4.0.0</modelVersion>
    <packaging>war</packaging>
    <name>My Project</name>
    <url>http://maven.apache.org</url>

    <build><finalName>MyProject</finalName></build>

    <properties>
        <maven.compiler.source>1.6</maven.compiler.source>
        <maven.compiler.target>1.6</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.0.13</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.8.1</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <!-- if your container implements Servlet API older than 3.0, use "jersey-container-servlet-core" -->
            <artifactId>jersey-container-servlet</artifactId>
            <version>2.6</version>
        </dependency>
        <!-- Required only when you are using JAX-RS Client -->
        <dependency>
            <groupId>org.glassfish.jersey.core</groupId>
            <artifactId>jersey-client</artifactId>
            <version>2.6</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <!-- scope>provided</scope -->
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.jaxrs</groupId>
            <artifactId>jackson-jaxrs-json-provider</artifactId>
            <version>2.4.2</version>
        </dependency>

        <dependency>
            <groupId>io.swagger</groupId>
            <artifactId>swagger-jersey2-jaxrs</artifactId>
            <version>1.5.4</version>
        </dependency>

    </dependencies>


</project>

最后，为了完整起见，这是我的 Java 类的摘录：

package org.something;

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiResponse;
import io.swagger.annotations.ApiResponses;

import java.util.Map;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Response;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Path("/dataset")
@Produces({ "application/json" })
@Api(value = "/dataset", description = "the dataset API")
public class DatasetApi  {

    private static final Logger log = LoggerFactory.getLogger(DatasetApi.class);

    @GET
    @ApiOperation(value = "All the available datasets.", notes = "Available datasets", response = Map.class, responseContainer = "Map")
    @ApiResponses(value = { @ApiResponse(code = 200, message = "Map of the available datasets", response = Map.class, responseContainer = "Map") })
    public Map<String, String> datasetGet() {
        try {
            log.info("Returning list of dataset");
            return Storage.datasets().getDatasets();
        } catch(Exception e) {
            log.info("Exception!", e);
            throw new WebJsonException(e, Response.Status.INTERNAL_SERVER_ERROR);
        }
    }

}

理想情况下，我想要一个类，它要么在之前调用，要么包装 swagger 逻辑（通过在web.xml）并做了一个简单的mapper.setSerializationInclusion(Include.NON_NULL);这解决了所有的麻烦，但我不知道这是否以及如何可能。

我花了一周的时间，在发布问题后几个小时就找到了解决方案，对此感到抱歉。

看来在web.xml缺少了io.swagger.jaxrs.listing.SwaggerSerializersServletContainer 中的类，完整部分是：

<servlet>
    <servlet-name>jersey</servlet-name>
    <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
    <init-param>
    <param-name>jersey.config.server.provider.classnames</param-name>
    <param-value>
        io.swagger.jersey.listing.ApiListingResourceJSON,
        io.swagger.jaxrs.listing.SwaggerSerializers,
        org.something.DatasetApi
    </param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

随着io.swagger.jaxrs.listing.SwaggerSerializers现在一切都按预期进行。