如何利用Retrofit+RxJava实现网络请求的异常处理

public class ExceptionHandle {  private static final int UNAUTHORIZED = 401;  private static final int FORBIDDEN = 403;  private static final int NOT_FOUND = 404;  private static final int REQUEST_TIMEOUT = 408;  private static final int INTERNAL_SERVER_ERROR = 500;  private static final int BAD_GATEWAY = 502;  private static final int SERVICE_UNAVAILABLE = 503;  private static final int GATEWAY_TIMEOUT = 504;  public static ResponseException handleException(Throwable e){    //转换成ResponseException,根据状态码判定错误信息    ResponseException ex;    if(e instanceof HttpException){      HttpException httpException=(HttpException)e;      /**       * 传入状态码，根据状态码判定错误信息       */      ex=new ResponseException(e,ERROR.HTTP_ERROR);      switch (httpException.code()){        case UNAUTHORIZED:          ex.message="未验证";          break;        case FORBIDDEN:          ex.message="服务禁止访问";          break;        case NOT_FOUND:          ex.message="服务不存在";          break;        case REQUEST_TIMEOUT:          ex.message="请求超时";          break;        case GATEWAY_TIMEOUT:          ex.message="网关超时";          break;        case INTERNAL_SERVER_ERROR:          ex.message="服务器内部错误";          break;        case BAD_GATEWAY:          break;        case SERVICE_UNAVAILABLE:          break;        default:          ex.message = "网络错误";          break;      }      return ex;    }else if(e instanceof JsonParseException        || e instanceof JSONException        || e instanceof ParseException){      ex=new ResponseException(e,ERROR.PARSE_ERROR);      ex.message="解析错误";      return ex;    }else if(e instanceof ConnectException){      ex=new ResponseException(e,ERROR.NETWORD_ERROR);      ex.message="连接失败";      return ex;    }else if(e instanceof javax.net.ssl.SSLHandshakeException){      ex=new ResponseException(e,ERROR.SSL_ERROR);      ex.message="证书验证失败";      return ex;    }else {      ex=new ResponseException(e,ERROR.UNKNOWN);      ex.message="未知错误";      return ex;    }  }  /**   * 约定异常   */ public static  class ERROR{    /**     * 自定义异常     */    private static final int UNAUTHORIZED = 401;//请求用户进行身份验证    private static final int UNREQUEST=403;//服务器理解请求客户端的请求，但是拒绝执行此请求    private static final int UNFINDSOURCE=404;//服务器无法根据客户端的请求找到资源    private static final int SEVERERROR=500;//服务器内部错误，无法完成请求。    /**     * 协议出错     */    public static final int HTTP_ERROR = 1003;    /**     * 未知错误     */    public static final int UNKNOWN = 1000;    /**     * 解析错误     */    public static final int PARSE_ERROR = 1001;    /**     * 网络错误     */    public static final int NETWORD_ERROR = 1002;    /**     * 证书出错     */    public static final int SSL_ERROR = 1005;  }  /**   * 自定义Throwable   */  public static class ResponseThrowable extends Exception{    public int code;    public String message;    public ResponseThrowable(Throwable throwable,int code){      super(throwable);      this.code=code;    }  }  /**   * 服务器异常   */  public class ServerException extends RuntimeException{    public int code;    public String message;  }  /**   * 统一异常类，便于处理   */  public static class ResponseException extends Exception{    public int code;    public String message;    public ResponseException (Throwable throwable,int code){      super(throwable);      this.code=code;    }  }}

public abstract class BaseObserver<T> implements Observer<T> {  private Context context;  public BaseObserver(Context context){    this.context=context;  }  @Override  public void onSubscribe(Disposable d) {  }  @Override  public void onNext(T t) {  }  @Override  public void onError(Throwable e) {    if(e instanceof ExceptionHandle.ResponseException){      onError((ExceptionHandle.ResponseException)e);    }else{      onError(new ExceptionHandle.ResponseException(e,ExceptionHandle.ERROR.UNKNOWN));    }  }  @Override  public void onComplete() {  }  public abstract void onError(ExceptionHandle.ResponseException exception);}

  public static class HandleFuc<T> implements Function<UserGuideSoftConfigRForm<UserGuideSoftConfigPageInfo<List<UserguideSoftConfig>>>, T> {    @Override    public T apply(UserGuideSoftConfigRForm<UserGuideSoftConfigPageInfo<List<UserguideSoftConfig>>> Response) {      if (!Response.getCode().equals("200")){        Throwable e=new Throwable("约定错误");        /**         * 可以根据不同的状态嘛返回不同的提示信息         * 与服务器约定返回异常信息         */        ExceptionHandle.ResponseException responseException = new ExceptionHandle.ResponseException(e, ExceptionHandle.ERROR.HTTP_ERROR);        return (T) Observable.error(responseException);//发出错误异常      }      return (T) Observable.just(Response);//发出服务器数据，返回Observable<Response>    }  }  //处理错误的变换  public static class ErrorTransformer<T> implements ObservableTransformer {    @Override    public Observable<T> apply(Observable upstream) {      return (Observable<T>) upstream.flatMap(new HandleFuc<T>());//flatMap会重新创建一个Observable,当它处理完事件后会汇入原先的Observable对象。    }  }

@Provides  ErrorTransformer provideErrorTransformer(){    return new ErrorTransformer();  } public Observable<UserGuideSoftConfigRForm<UserGuideSoftConfigPageInfo<List<UserguideSoftConfig>>>> getApplication(PageParmForm pageParmForm){    return retrofit.create(Service.class)        .getApplicationList(pageParmForm)        .compose(errorTransformer)        .subscribeOn(Schedulers.io())        .observeOn(AndroidSchedulers.mainThread());  }

new NetRepository().getApplication(new PageParmForm(Constant.orderStr,Constant.pageNum,Constant.pageSize))    .subscribe(new BaseObserver<UserGuideSoftConfigRForm<UserGuideSoftConfigPageInfo<List<UserguideSoftConfig>>>>(NetWorkActivity.this) {      @Override      public void onError(ExceptionHandle.ResponseException exception) {        myToast.showToast(NetWorkActivity.this,exception.getMessage());        Log.d("carhandbook",exception.getMessage());      }      @Override      public void onNext(UserGuideSoftConfigRForm<UserGuideSoftConfigPageInfo<List<UserguideSoftConfig>>> Response) {        data=Response.getData().getList();        code=Response.getCode();        myToast.showToast(NetWorkActivity.this,code);        generateAdapter.setData(data);        generateAdapter.notifyDataSetChanged();      }    });