java - 使用 Retrofit 和 Gson 以及返回动态顶级 JSON 的 api

Question

我使用 Retrofit 访问以下 api:

https://api.nasa.gov/neo/rest/v1/feed?api_key=DEMO_KEY

near_earth_objects对象包含多个数组，每个数组都有一个代表日期的键。如果您访问不同的日期，该值显然会发生变化。

像往常一样，我根据返回的 JSON 结构定义了 POJO。以下是我的主要响应类:

public class AsteroidResponse {

    private Links links;

    @SerializedName("element_count")
    private Integer elementCount;

    @SerializedName("near_earth_objects")
    private NearEarthObjects nearEarthObjects;

    private Map<String, Object> additionalProperties = new HashMap<String, Object>();
    //getters and setters
}

NearEarthObjects类如下所示:

public class NearEarthObjects {

    private List<Observation> observation = new ArrayList<>();

    private Map<String, Object> additionalProperties = new HashMap<String, Object>();
    //getters and setters
}

我之前遇到过这个问题，并且能够使用 Map<String, SomeCustomModel>让它自动解析并将日期设置为 map 中的键。在围绕 SO 的一些答案中建议了这种方法。

在这种情况下我尝试做同样的事情，将上述类替换为如下所示:

public class NearEarthObjects {

    private Map<String, Observation> observation = new HashMap<>();

    private Map<String, Object> additionalProperties = new HashMap<String, Object>();
}

不幸的是，这次这个方法似乎没有按预期工作。 map 返回为空。可能是什么问题？构建模型以正确解析返回的 JSON 的最佳方法是什么？

Answer 1

我认为解析对象near_earth_objects内的Json数据的简单方法是构造你的json返回如下:

"near_earth_objects":[  
   {  
      "date":"2016-11-07",
      "data":[  
         {  
            "links":{  
               "self":"https://api.nasa.gov/neo/rest/v1/neo/3758255?api_key=DEMO_KEY"
            },
            "neo_reference_id":"3758255",
            "name":"(2016 QH44)",
            "nasa_jpl_url":"http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3758255",
            "absolute_magnitude_h":22.381,
            "estimated_diameter":{  
               "kilometers":{  
                  "estimated_diameter_min":0.0887881438,
                  "estimated_diameter_max":0.1985363251
               },
               "meters":{  
                  "estimated_diameter_min":88.7881437713,
                  "estimated_diameter_max":198.5363250687
               },
               "miles":{  
                  "estimated_diameter_min":0.0551703777,
                  "estimated_diameter_max":0.1233647148
               },
               "feet":{  
                  "estimated_diameter_min":291.2996936107,
                  "estimated_diameter_max":651.3659167384
               }
            },
            "is_potentially_hazardous_asteroid":false,
            "close_approach_data":[  
               {  
                  "close_approach_date":"2016-11-07",
                  "epoch_date_close_approach":1478505600000,
                  "relative_velocity":{  
                     "kilometers_per_second":"9.9505291907",
                     "kilometers_per_hour":"35821.9050865416",
                     "miles_per_hour":"22258.3387466903"
                  },
                  "miss_distance":{  
                     "astronomical":"0.1045395934",
                     "lunar":"40.6659011841",
                     "kilometers":"15638901",
                     "miles":"9717563"
                  },
                  "orbiting_body":"Earth"
               }
            ]
         },
         {  
            "links":{  
               "self":"https://api.nasa.gov/neo/rest/v1/neo/3758255?api_key=DEMO_KEY"
            },
            "neo_reference_id":"3758255",
            "name":"(2016 QH44)",
            "nasa_jpl_url":"http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3758255",
            "absolute_magnitude_h":22.381,
            "estimated_diameter":{  
               "kilometers":{  
                  "estimated_diameter_min":0.0887881438,
                  "estimated_diameter_max":0.1985363251
               },
               "meters":{  
                  "estimated_diameter_min":88.7881437713,
                  "estimated_diameter_max":198.5363250687
               },
               "miles":{  
                  "estimated_diameter_min":0.0551703777,
                  "estimated_diameter_max":0.1233647148
               },
               "feet":{  
                  "estimated_diameter_min":291.2996936107,
                  "estimated_diameter_max":651.3659167384
               }
            },
            "is_potentially_hazardous_asteroid":false,
            "close_approach_data":[  
               {  
                  "close_approach_date":"2016-11-07",
                  "epoch_date_close_approach":1478505600000,
                  "relative_velocity":{  
                     "kilometers_per_second":"9.9505291907",
                     "kilometers_per_hour":"35821.9050865416",
                     "miles_per_hour":"22258.3387466903"
                  },
                  "miss_distance":{  
                     "astronomical":"0.1045395934",
                     "lunar":"40.6659011841",
                     "kilometers":"15638901",
                     "miles":"9717563"
                  },
                  "orbiting_body":"Earth"
               }
            ]
         }
      ]
   }
 // The other objects 
]

如果你想解析动态 key 。您可以使用此链接: How to parse a dynamic JSON key in a Nested JSON result?