Retrofit2 Android:预期 BEGIN_ARRAY 但在第 1 行第 2 列路径 $ 处 BEGIN_OBJECT
Retrofit2 Android: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
我知道这不是第一次有人问这个问题,但是使用 Retrofit2 我找不到正确的解决方案来解决我的问题。我按照在线教程进行操作,效果很好。当我将相同的代码应用到我自己的端点时,我得到了这个异常:java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
我不知道如何解决这个问题。
接口:
public interface MyApiService {
// Is this right place to add these headers?
@Headers({"application-id: MY-APPLICATION-ID",
"secret-key: MY-SECRET-KEY",
"application-type: REST"})
@GET("Music")
Call<List<Music>> getMusicList();
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(MySettings.REST_END_POINT)
.addConverterFactory(GsonConverterFactory.create())
.build();
}
客户代码:
MyApiService service = MyApiService.retrofit.create(MyApiService.class);
Call<List<Music>> call = service.getMusicList();
call.enqueue(new Callback<List<Music>>() {
@Override
public void onResponse(Call<List<Music>> call, Response<List<Music>> response) {
Log.e("MainActivity", response.body().
}
@Override
public void onFailure(Call<List<Music>> call, Throwable t) {
Log.e("MainActivity", t.toString());
}
});
此代码使用此负载:
[
{
"login": "JakeWharton",
"id": 66577,
"avatar_url": "https://avatars.githubusercontent.com/u/66577?v=3",
"gravatar_id": "",
"url": "https://api.github.com/users/JakeWharton",
"html_url": "https://github.com/JakeWharton",
"followers_url": "https://api.github.com/users/JakeWharton/followers",
"following_url": "https://api.github.com/users/JakeWharton/following{/other_user}",
"gists_url": "https://api.github.com/users/JakeWharton/gists{/gist_id}",
"starred_url": "https://api.github.com/users/JakeWharton/starred{/owner}{/repo}",
"subscriptions_url": "https://api.github.com/users/JakeWharton/subscriptions",
"organizations_url": "https://api.github.com/users/JakeWharton/orgs",
"repos_url": "https://api.github.com/users/JakeWharton/repos",
"events_url": "https://api.github.com/users/JakeWharton/events{/privacy}",
"received_events_url": "https://api.github.com/users/JakeWharton/received_events",
"type": "User",
"site_admin": false,
"contributions": 741
},
{....
但这个不是:
{
"offset": 0,
"data": [
{
"filename": "E743_1458662837071.mp3",
"created": 1458662854000,
"publicUrl": "https://api.backendless.com/dbb77803-1ab8-b994-ffd8-65470fa62b00/v1/files/music/E743_1458662837071.mp3",
"___class": "Music",
"description": "",
"likeCount": 0,
"title": "hej Susanne. ",
"ownerId": "E743756F-E114-6892-FFE9-BCC8C072E800",
"updated": null,
"objectId": "DDD8CB3D-ED66-0D6F-FFA5-B14543ABC800",
"__meta": "{\"relationRemovalIds\":{},\"selectedProperties\":[\"filename\",\"created\",\"publicUrl\",\"___class\",\"description\",\"likeCount\",\"title\",\"ownerId\",\"updated\",\"objectId\"],\"relatedObjects\":{}}"
},
{...
我的音乐class:
public class Music {
private String ownerId;
private String filename;
private String title;
private String description;
private String publicUrl;
private int likeCount;
// Getters & Setters
}
当您说 "This code is working with this payload:... but not with this one:..." 时,这是意料之中的,这就是它应该如何工作。事实上,错误消息告诉您,在将 json 转换为 java 对象时,调用需要 json 中的数组,但却得到了一个对象。
这次通话:
@GET("Music")
Call<List<Music>> getMusicList();
需要一个 Music
对象的列表,这就是它与 json:
一起工作的原因
[
{
"login": "JakeWharton",
...
},
...
]
因为 json 本身就是一个 Music
对象的数组(Retrofit 可以在 json 数组与 java 列表之间进行转换)。对于第二个 json 你只有一个对象而不是一个数组(注意缺少 [...]
)。为此,您需要使用映射到 json 的另一个模型创建另一个调用。假设您已将模型命名为 MusicList
。下面是调用的样子:
@GET("Music")
Call<MusicList> getMusicList();
(请注意,如果要保留第一个调用和这个调用,您可能需要更改方法名称)。
MusicList
模型看起来像这样:
public class MusicList {
@SerializedName("data")
private List<Music> musics;
// ...
}
我假设 data
数组是 Music
对象的列表,但我注意到 json 是完全不同的。您可能也需要对此进行调整,但我想您已经了解了这里的情况。
我遇到了这个问题。这是因为有效载荷是一个对象而不是对象数组。所以我删除了列表。
代码示例
UserAPI.java
public interface UserAPI {
@GET("login/cellphone")
Call<LoginResponse> login(@Query("phone") String phone,
@Query("password") String password);
}
调用代码
Retrofit retrofit = new Retrofit
.Builder()
.addConverterFactory(GsonConverterFactory.create())
.baseUrl(Constant.CLOUD_MUSIC_API_BASE_URL)
.build();
UserAPI userAPI = retrofit.create(UserAPI.class);
userAPI.login(phone, password).enqueue(new Callback<LoginResponse>() {
@Override
public void onResponse(Call<LoginResponse> call, Response<LoginResponse> response) {
System.out.println("onResponse");
System.out.println(response.body().toString());
}
@Override
public void onFailure(Call<LoginResponse> call, Throwable t) {
System.out.println("onFailure");
System.out.println(t.fillInStackTrace());
}
});
我知道这不是第一次有人问这个问题,但是使用 Retrofit2 我找不到正确的解决方案来解决我的问题。我按照在线教程进行操作,效果很好。当我将相同的代码应用到我自己的端点时,我得到了这个异常:java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
我不知道如何解决这个问题。
接口:
public interface MyApiService {
// Is this right place to add these headers?
@Headers({"application-id: MY-APPLICATION-ID",
"secret-key: MY-SECRET-KEY",
"application-type: REST"})
@GET("Music")
Call<List<Music>> getMusicList();
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(MySettings.REST_END_POINT)
.addConverterFactory(GsonConverterFactory.create())
.build();
}
客户代码:
MyApiService service = MyApiService.retrofit.create(MyApiService.class);
Call<List<Music>> call = service.getMusicList();
call.enqueue(new Callback<List<Music>>() {
@Override
public void onResponse(Call<List<Music>> call, Response<List<Music>> response) {
Log.e("MainActivity", response.body().
}
@Override
public void onFailure(Call<List<Music>> call, Throwable t) {
Log.e("MainActivity", t.toString());
}
});
此代码使用此负载:
[
{
"login": "JakeWharton",
"id": 66577,
"avatar_url": "https://avatars.githubusercontent.com/u/66577?v=3",
"gravatar_id": "",
"url": "https://api.github.com/users/JakeWharton",
"html_url": "https://github.com/JakeWharton",
"followers_url": "https://api.github.com/users/JakeWharton/followers",
"following_url": "https://api.github.com/users/JakeWharton/following{/other_user}",
"gists_url": "https://api.github.com/users/JakeWharton/gists{/gist_id}",
"starred_url": "https://api.github.com/users/JakeWharton/starred{/owner}{/repo}",
"subscriptions_url": "https://api.github.com/users/JakeWharton/subscriptions",
"organizations_url": "https://api.github.com/users/JakeWharton/orgs",
"repos_url": "https://api.github.com/users/JakeWharton/repos",
"events_url": "https://api.github.com/users/JakeWharton/events{/privacy}",
"received_events_url": "https://api.github.com/users/JakeWharton/received_events",
"type": "User",
"site_admin": false,
"contributions": 741
},
{....
但这个不是:
{
"offset": 0,
"data": [
{
"filename": "E743_1458662837071.mp3",
"created": 1458662854000,
"publicUrl": "https://api.backendless.com/dbb77803-1ab8-b994-ffd8-65470fa62b00/v1/files/music/E743_1458662837071.mp3",
"___class": "Music",
"description": "",
"likeCount": 0,
"title": "hej Susanne. ",
"ownerId": "E743756F-E114-6892-FFE9-BCC8C072E800",
"updated": null,
"objectId": "DDD8CB3D-ED66-0D6F-FFA5-B14543ABC800",
"__meta": "{\"relationRemovalIds\":{},\"selectedProperties\":[\"filename\",\"created\",\"publicUrl\",\"___class\",\"description\",\"likeCount\",\"title\",\"ownerId\",\"updated\",\"objectId\"],\"relatedObjects\":{}}"
},
{...
我的音乐class:
public class Music {
private String ownerId;
private String filename;
private String title;
private String description;
private String publicUrl;
private int likeCount;
// Getters & Setters
}
当您说 "This code is working with this payload:... but not with this one:..." 时,这是意料之中的,这就是它应该如何工作。事实上,错误消息告诉您,在将 json 转换为 java 对象时,调用需要 json 中的数组,但却得到了一个对象。
这次通话:
@GET("Music")
Call<List<Music>> getMusicList();
需要一个 Music
对象的列表,这就是它与 json:
[
{
"login": "JakeWharton",
...
},
...
]
因为 json 本身就是一个 Music
对象的数组(Retrofit 可以在 json 数组与 java 列表之间进行转换)。对于第二个 json 你只有一个对象而不是一个数组(注意缺少 [...]
)。为此,您需要使用映射到 json 的另一个模型创建另一个调用。假设您已将模型命名为 MusicList
。下面是调用的样子:
@GET("Music")
Call<MusicList> getMusicList();
(请注意,如果要保留第一个调用和这个调用,您可能需要更改方法名称)。
MusicList
模型看起来像这样:
public class MusicList {
@SerializedName("data")
private List<Music> musics;
// ...
}
我假设 data
数组是 Music
对象的列表,但我注意到 json 是完全不同的。您可能也需要对此进行调整,但我想您已经了解了这里的情况。
我遇到了这个问题。这是因为有效载荷是一个对象而不是对象数组。所以我删除了列表。
代码示例
UserAPI.java
public interface UserAPI {
@GET("login/cellphone")
Call<LoginResponse> login(@Query("phone") String phone,
@Query("password") String password);
}
调用代码
Retrofit retrofit = new Retrofit
.Builder()
.addConverterFactory(GsonConverterFactory.create())
.baseUrl(Constant.CLOUD_MUSIC_API_BASE_URL)
.build();
UserAPI userAPI = retrofit.create(UserAPI.class);
userAPI.login(phone, password).enqueue(new Callback<LoginResponse>() {
@Override
public void onResponse(Call<LoginResponse> call, Response<LoginResponse> response) {
System.out.println("onResponse");
System.out.println(response.body().toString());
}
@Override
public void onFailure(Call<LoginResponse> call, Throwable t) {
System.out.println("onFailure");
System.out.println(t.fillInStackTrace());
}
});