默认情况下，Gson只支持它的@SerializedName注解来指定自定义JSON成员名称。
假设您正在使用的@Key注解在运行时可用（@Retention(RUNTIME)），则可以编写一个自定义FieldNamingStrategy：

public class KeyFieldNamingStrategy implements FieldNamingStrategy {
    private final FieldNamingStrategy delegate;

    public KeyFieldNamingStrategy(FieldNamingStrategy delegate) {
        this.delegate = delegate;
    }

    @Override
    public String translateName(Field f) {
        Key key = f.getAnnotation(Key.class);
        if (key == null) {
            // No annotation, use delegate
            return delegate.translateName(f);
        } else {
            return key.value();
        }
    }
}

然后将其注册到GsonBuilder：

Gson gson = new GsonBuilder()
    // Uses IDENTITY as delegate, which uses field names as is
    .setFieldNamingStrategy(new KeyFieldNamingStrategy(FieldNamingPolicy.IDENTITY))
    .create();