英文:
Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $ using Retrofit
问题
I'm here to help with the translation. Here's the translation of the code parts you provided:
我正在尝试使用 Retrofit 根据特定的 ID 从数据库获取数据，但出现错误时调用 onError：
> com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $
Students 类：
public class Students implements Parcelable {
private int id;
@SerializedName("first_name")
private String firstName;
@SerializedName("last_name")
private String lastName;
private String course;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getCourse() {
return course;
}
public void setCourse(String course) {
this.course = course;
}
public String getScore() {
return score;
}
public void setScore(String score) {
this.score = score;
}
private String score;
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(this.id);
dest.writeString(this.firstName);
dest.writeString(this.lastName);
dest.writeString(this.course);
dest.writeString(this.score);
}
public void readFromParcel(Parcel source) {
this.id = source.readInt();
this.firstName = source.readString();
this.lastName = source.readString();
this.course = source.readString();
this.score = source.readString();
}
public Students() {
}
protected Students(Parcel in) {
this.id = in.readInt();
this.firstName = in.readString();
this.lastName = in.readString();
this.course = in.readString();
this.score = in.readString();
}
public static final Parcelable.Creator<Students> CREATOR = new Parcelable.Creator<Students>() {
@Override
public Students createFromParcel(Parcel source) {
return new Students(source);
}
@Override
public Students[] newArray(int size) {
return new Students[size];
}
};
}
这是我的 Retrofit 接口代码：
public interface Api {
@GET(url)
Single<Students> getStudent(@Query("id") int id);
}
以及我的 MainActivity：
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(URL)
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava3CallAdapterFactory.create())
.build();
Api api = retrofit.create(Api.class);
api.getStudent(339).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(new SingleObserver<Students>() {
@Override
public void onSubscribe(@NonNull Disposable d) {
}
@Override
public void onSuccess(@NonNull Students students) {
Log.i(TAG, "onSuccess: "+students);
}
@Override
public void onError(@NonNull Throwable e) {
Log.e(TAG, "onError: "+e );
}
});
如果您需要更多帮助或有其他问题，请随时提出。
英文:
I am Trying to get a data by a specific id from database using Retrofit but onError calls:
> com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $
Students class:
public class Students implements Parcelable {
private int id;
@SerializedName("first_name")
private String firstName;
@SerializedName("last_name")
private String lastName;
private String course;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getCourse() {
return course;
}
public void setCourse(String course) {
this.course = course;
}
public String getScore() {
return score;
}
public void setScore(String score) {
this.score = score;
}
private String score;
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(this.id);
dest.writeString(this.firstName);
dest.writeString(this.lastName);
dest.writeString(this.course);
dest.writeString(this.score);
}
public void readFromParcel(Parcel source) {
this.id = source.readInt();
this.firstName = source.readString();
this.lastName = source.readString();
this.course = source.readString();
this.score = source.readString();
}
public Students() {
}
protected Students(Parcel in) {
this.id = in.readInt();
this.firstName = in.readString();
this.lastName = in.readString();
this.course = in.readString();
this.score = in.readString();
}
public static final Parcelable.Creator<Students> CREATOR = new Parcelable.Creator<Students>() {
@Override
public Students createFromParcel(Parcel source) {
return new Students(source);
}
@Override
public Students[] newArray(int size) {
return new Students[size];
}
};
}
and here is my retrofit interface code:
public interface Api {
@GET(url)
Single<Students> getStudent(@Query("id") int id);
}
and my MainActivity:
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(URL)
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJava3CallAdapterFactory.create())
.build();
Api api = retrofit.create(Api.class);
api.getStudent(339).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(new SingleObserver<Students>() {
@Override
public void onSubscribe(@NonNull Disposable d) {
}
@Override
public void onSuccess(@NonNull Students students) {
Log.i(TAG, "onSuccess: "+students);
}
@Override
public void onError(@NonNull Throwable e) {
Log.e(TAG, "onError: "+e );
}
});
can you please tell me if I am doing something wrong here?
答案1
得分: 1
问题在于代码期望一个JSON对象（用花括号{}括起来），但实际遇到了一个JSON数组（用方括号[]括起来）。
问题出在你解析数据的方式上。
英文:
The issue is that the code is expecting a JSON object (enclosed within curly braces {}) but encountered a JSON array (enclosed within square brackets []) instead.
The issue is with the way you are parsing the data.
答案2
得分: 0
错误是因为您的API响应以数组形式开始：
[
{ "a": 1 }
]
它应该以对象形式开始，如下所示：
{
"a": 1
}
英文:
The error occur because your api response begin as an array:
[
{ "a": 1 }
]
It should begin as an object, like as:
{
"a": 1
}
</details>
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