使用Retrofit和GSON解析JSON时,尝试解析并获取回调时出错.

Question

我正在使用Retrofit处理针对Android应用程序的API调用.我试图让Retrofit处理JSON的解析,并根据我创建的POJO创建一个对象列表.

我收到的错误是" com.google.gson.JsonSyntaxException:java.lang.IllegalStateException:预期字符串但在第1行第176行是BEGIN_OBJECT".

我使用JsonSchema2Pojo来生成我的java类.类和关联的JSON如下所示.

{"status":"success","data":[{"sort_key":1,"event_id":1947357,"title":"2014 US Open Tennis Session 15 (Mens\/Womens Round of 16)","datetime_utc":"2014-09-01T15:00:00","venue":{"city":"Flushing","name":"Louis Armstrong Stadium","extended_address":"Flushing, NY 11368","url":"https:\/\/seatgeek.com\/venues\/louis-armstrong-stadium\/tickets\/?aid=10918","country":"US","display_location":"Flushing, NY","links":[],"slug":"louis-armstrong-stadium","state":"NY","score":0.73523,"postal_code":"11368","location":{"lat":40.7636,"lon":-73.83},"address":"1 Flushing Meadows Corona Park Road","timezone":"America\/New_York","id":2979},"images":["https:\/\/chairnerd.global.ssl.fastly.net\/images\/performers-landscape\/us-open-tennis-45e2d9\/5702\/huge.jpg","https:\/\/chairnerd.global.ssl.fastly.net\/images\/performers\/5702\/us-open-tennis-c1ccf7\/medium.jpg","https:\/\/chairnerd.global.ssl.fastly.net\/images\/performers\/5702\/us-open-tennis-01f513\/large.jpg","https:\/\/chairnerd.global.ssl.fastly.net\/images\/performers\/5702\/us-open-tennis-4e07f2\/small.jpg"]}

从此我相信我需要生成3个POJO,我的更高级别的"EventObject"类,位置类和Venue类.这些类及其变量如下:

EventObject类:

public class EventObject {

private Integer sortKey;
private Integer eventId;
private String title;
private String datetimeUtc;
private Venue venue;
private List<String> images = new ArrayList<String>();
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

位置等级:

public class Location {

private Float lat;
private Float lon;
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

地点类别:

public class Venue {

private String city;
private String name;
private String extendedAddress;
private String url;
private String country;
private String displayLocation;
private List<Object> links = new ArrayList<Object>();
private String slug;
private String state;
private Float score;
private String postalCode;
private Location location;
private String address;
private String timezone;
private Integer id;
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

我的Api Call界面如下:

public interface UserEvents {

@GET("/user/get_events")
void getEvents(@Header("Authorization")String token_id,
@Query("event_type")String event_type,
@Query("postal_code")int postalCode,
@Query("per_page") int perPage ,
@Query("lat") int lat,
@Query("lon") int lon,
@Query("month")int month,
@Query("page")int page,
Callback<List<EventObject>>callback) ;

}

以下是我的代码中的实现:

UserEvents mUserEvents = mRestAdapter.create(UserEvents.class);
mUserEvents.getEvents(token_Id, "sports",11209,25,0, 0, 9, 2, new Callback <List<EventObject>>() {
@Override
public void success(List<EventObject> eventObjects, retrofit.client.Response response) {
Log.d(TAG,"Success");
            }

这里有很多,但我相信我可能会错误地处理JSON.当我将我的JSON复制并粘贴到Pojo生成器时,我没有包含"status:success"数据:{

我基本上只使用了数组中元素的整个条目(从{sort_key向前到下一个排序键的所有内容)并将其推送到转换器中.

这是我第一次尝试Retrofit和API工作,并解析任何复杂的东西.我希望其他人可以指出的东西.我也用Google搜索,我可以把它排除在外,没有运气.

谢谢你的期待.

Answer 1

主要问题是您没有获得响应的根元素.您需要创建一个实体"响应"来获取项目状态和数据.它看起来像这样:

public class RootObject {

    @Expose
    private String status;
    @Expose
    private EventObject data;

    //getters and setters here
}

然后当你进行回调时,你应该指向你的RootObject, mUserEvents.getEvents(token_Id, "sports",11209,25,0, 0, 9, 2, new Callback <RootObject>()

还有一件事,Retrofit使用GSON来解析你的json响应.这意味着在创建实体时,变量需要与响应中的对象名称匹配.如果不是,你需要告诉GSON如何映射变量,如下所示:

@SerializedName("extended_address")
@Expose
private String extendedAddress;

在这种情况下,json中的值是"extended_address",并将映射到String extendedAddress.如果你没有放那@SerializedName行,那么解析就会失败.如果要跳过该行,则可以调用变量"extended_address",使其与响应匹配.

的@Expose是通过GSON需要来解析它下面的变量.如果变量没有变量,那么GSON将忽略该解析.因此,您需要修复实体@Expose和@SerializedName实体,以便GSON正常工作.

希望能帮助到你.