具体使用见https://github.com/caiyoufei/ABase

1.ParameterizedType

import cc.ab.base.net.http.response.BaseResponse;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.List;
import org.jetbrains.annotations.NotNull;
public class BaseParameterizedTypeImpl implements ParameterizedType {
  private final Class raw;
  private final Type[] args;

  private BaseParameterizedTypeImpl(Class raw, Type[] args) {
    this.raw = raw;
    this.args = args != null ? args : new Type[0];
  }

  public static Type typeOne(Class<?> clazz) {
    return new BaseParameterizedTypeImpl(BaseResponse.class, new Class[] { clazz });
  }

  public static Type typeList(Class<?> clazz) {
    // 生成List<T> 中的 List<T>
    Type listType = new BaseParameterizedTypeImpl(List.class, new Class[] { clazz });
    // 根据List<T>生成完整的Response<List<T>>
    return new BaseParameterizedTypeImpl(BaseResponse.class, new Type[] { listType });
  }

  @NotNull @Override
  public Type[] getActualTypeArguments() {
    return args;
  }

  @NotNull @Override
  public Type getRawType() {
    return raw;
  }

  @Override
  public Type getOwnerType() {
    return null;
  }
}

2.BaseResponse

data class BaseResponse<out T>(
  val errorCode: Int = -1,//正常接口使用的状态码
  var errorMsg: String? = null,//code异常对应的信息提示
  val data: T? = null//正常返回的数据信息
)

3.真正转换

 private inline fun <reified T> flatMapSingle(
    result: Result<String, FuelError>
  ): Single<BaseResponse<T>> {
    return if (result.component2() == null) {
      Single.just(
          converWanData(result.component1(), BaseParameterizedTypeImpl.typeOne(T::class.java))
      )
    } else {
      Single.error(converFuelError(result.component2()))
    }
  }

  private inline fun <reified T> flatMapSingleList(
    result: Result<String, FuelError>
  ): Single<BaseResponse<MutableList<T>>> {
    return if (result.component2() == null) {
      Single.just(
          converWanData(result.component1(), BaseParameterizedTypeImpl.typeList(T::class.java))
      )
    } else {
      Single.error(converFuelError(result.component2()))
    }
  }

  //数据转换(可能抛出异常)
  @Throws
  private fun <T> converWanData(
    response: String?,
    type: Type
  ): BaseResponse<T> {
    if (response.isNullOrBlank()) throw converDataError()
    try {
      val result: BaseResponse<T> = GsonUtils.fromJson(response, type)
      if (globalErrorCode.contains(result.errorCode)) {
        result.errorMsg = null
        dealGlobalErrorCode(result.errorCode)
      }
      return result
    } catch (e: Exception) {
      e.printStackTrace()
    }
    throw converDataError()
  }

  //统一处理
  private fun dealGlobalErrorCode(errorCode: Int) {
    val activity = ActivityUtils.getTopActivity()
    activity?.let { ac ->
      when (errorCode) {
        //未登录
        ErrorCode.NO_LOGIN -> {
          ac.runOnUiThread {
            ac.toast(R.string.need_login)
            LoginActivity.startActivity(ac)
          }
        }
        else -> {
        }
      }
    }
  }