1、Retrofit+RxJava优雅的处理服务器返回异常错误Retrofit+RxJava 优雅的处理服务器返回异常、错误异常&错误实际开发经常有这种情况,比如登录请求,接口返回的 信息包括请求返回的状态:失败还是成功,错误码,User对象等等。如果网络等原因引起的登录失败可以归结为异常,如果是用户信息输入错误导致的登录失败算是错误。假如服务器返回的是统一数据格式:/* * 标准数据格式 * param */public class Response public int state; public String message; public T data;网络异常导致的登录失败,在使用Ret
2、rofit+RxJava请求时都会直接调用subscribe的onError事件;密码错误导致的登录失败,在使用Retrofit+RxJava请求时都会调用subscribe的onNext事件;无论是异常还是错误,都要在subscribe里面处理异常信息,如下代码:APIWrapper.getInstance().login(username, password) .subscribe(new ObserverResponse() Override public void onCompleted() Override public void onError(Throwable e) Overr
3、ide public void onNext(Response data) if(data.state = 1001) /. else if(data.state = 1002) );现在我希望在发生任何错误的情况下,都会调用onError事件,并且由model来处理错误信息。那么,此时我们就应该有一个ExceptionEngine来处理事件流中的错误信息了。在工作流中处理异常在正常情况下,我们获取网络数据的流程通常如下:请求接口-解析数据-更新整个数据请求过程都是发生在Rx中的工作流之中。当有异常产生的时候,我们要尽量不在ui层里面进行判断,换句话说,我们没有必要去告诉ui层具体的错误信息,
4、只需要让他弹出一个信息(Toast或者Dialog)展示我们给它的信息就行。请求接口和数据解析都可能出错,所以在这两层进行错误处理。为了更好的解耦,我们通过拦截器拦截错误,然后根据错误类型分发信息。拦截器数据解析层的拦截器这个拦截器主要是为了获取具体的错误信息,分发给上层的UI,给用户以提示,增强用户体验。public Observable getWeather(String cityName) return weatherService.getWeather(cityName) /拦截服务器返回的错误 .map(new ServerResponseFunc() /HttpResultFunc
5、()为拦截onError事件的拦截器,后面会讲到,这里先忽略 .onErrorResumeNext(new HttpResponseFunc(); /拦截固定格式的公共数据类型Response,判断里面的状态码private class ServerResponseFunc implements Func1Response, T Override public T call(Response reponse) /对返回码进行判断,如果不是0,则证明服务器端返回错误信息了,便根据跟服务器约定好的错误码去解析异常 if (reponse.state != 0) /如果服务器端有错误信息返回,那么抛
6、出异常,让下面的方法去捕获异常做统一处理 throw new ServerException(reponse.state,reponse.message); /服务器请求数据成功,返回里面的数据实体 return reponse.data; 所以整个逻辑是这样的: 所以在前三步的过程中,只要发生异常(服务器返回的错误也抛出了)都会抛出,这时候就触发了RxJava的OnError事件。处理onError事件的拦截器这个拦截器主要是将异常信息转化为用户”能看懂”的友好提示。 private class HttpResponseFunc implements Func1Throwable, Obse
7、rvable Override public Observable call(Throwable throwable) /ExceptionEngine为处理异常的驱动器 return Observable.error(ExceptionEngine.handleException(throwable); 两个拦截器以前使用,代码如下:public Observable getWeather(String cityName) return weatherService.getWeather(cityName) /拦截服务器返回的错误 .map(new ServerResponseFunc()
8、/HttpResponseFunc()为拦截onError事件的拦截器 .onErrorResumeNext(new HttpResponseFunc(); 调用:APIWrapper.getInstance().getWeather(北京) .subscribe(new SampleProgressObserver(MainActivity.this) Override public void onNext(WeatherBean weatherBean) tv.setText(weatherBean.toString(); );相关类:public class RxSubscriber e
9、xtends ErrorSubscriber Override public void onStart() super.onStart(); DialogHelper.showProgressDlg(context, 正在加载数据); Override public void onCompleted() DialogHelper.stopProgressDlg(); Override protected void onError(ApiException ex) DialogHelper.stopProgressDlg(); Toast.makeText(context, ex.message
10、, Toast.LENGTH_SHORT).show(); Override public void onNext(T t) public abstract class ErrorSubscriber extends Observer Override public void onError(Throwable e) if(e instanceof ApiException) onError(ApiException)e); else onError(new ApiException(e,123); /* * 错误回调 */ protected abstract void onError(Ap
11、iException ex);处理异常的驱动器package ;import .ParseException;import com.google.gson.JsonParseException;import org.json.JSONException;import .ConnectException;import retrofit2.adapter.rxjava.HttpException;/* * Created by Lzx on 2016/7/11. */public class ExceptionEngine /对应HTTP的状态码 private static final int
12、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
13、; private static final int GATEWAY_TIMEOUT = 504; public static ApiException handleException(Throwable e) ApiException ex; if (e instanceof HttpException) /HTTP错误 HttpException httpException = (HttpException) e; ex = new ApiException(e, ERROR.HTTP_ERROR); switch(httpException.code() case UNAUTHORIZE
14、D: case FORBIDDEN: case NOT_FOUND: case REQUEST_TIMEOUT: case GATEWAY_TIMEOUT: case INTERNAL_SERVER_ERROR: case BAD_GATEWAY: case SERVICE_UNAVAILABLE: default: ex.message = 网络错误; /均视为网络错误 break; return ex; else if (e instanceof ServerException) /服务器返回的错误 ServerException resultException = (ServerExce
15、ption) e; ex = new ApiException(resultException, resultException.code); ex.message = resultException.message; return ex; else if (e instanceof JsonParseException | e instanceof JSONException | e instanceof ParseException) ex = new ApiException(e, ERROR.PARSE_ERROR); ex.message = 解析错误; /均视为解析错误 retur
16、n ex; else if(e instanceof ConnectException) ex = new ApiException(e, ERROR.NETWORD_ERROR); ex.message = 连接失败; /均视为网络错误 return ex; else ex = new ApiException(e, ERROR.UNKNOWN); ex.message = 未知错误; /未知错误 return ex; /* * 约定异常 */public class ERROR /* * 未知错误 */ public static final int UNKNOWN = 1000; /*
17、* 解析错误 */ public static final int PARSE_ERROR = 1001; /* * 网络错误 */ public static final int NETWORD_ERROR = 1002; /* * 协议出错 */ public static final int HTTP_ERROR = 1003;public class ApiException extends Exception public int code; public String message; public ApiException(Throwable throwable, int cod
18、e) super(throwable); this.code = code; public class ServerException extends RuntimeException public int code; public String message;DialogHelper.Javapublic class DialogHelper /* * 通用Dialog * */ / 因为本类不是activity所以通过继承接口的方法获取到点击的事件 public interface OnOkClickListener abstract void onOkClick(); /* * Lis
19、tener */ public interface OnCancelClickListener abstract void onCancelClick(); private static AlertDialog mDialog; public static void showDialog(Context context, String title, String content, final OnOkClickListener listenerYes, final OnCancelClickListener listenerNo) showDialog(context, context.get
20、String(android.R.string.ok), context.getString(android.R.string.cancel), title, content, listenerYes, listenerNo); public static void showDialog(Context context, String ok, String cancel, String title, String content, final OnOkClickListener listenerYes, final OnCancelClickListener listenerNo) Alert
21、Dialog.Builder builder = new AlertDialog.Builder(context); builder.setMessage(content); / 设置title builder.setTitle(title); / 设置确定按钮,固定用法声明一个按钮用这个setPositiveButton builder.setPositiveButton(ok, new DialogInterface.OnClickListener() public void onClick(DialogInterface dialog, int which) / 如果确定被电击 if (
22、listenerYes != null) listenerYes.onOkClick(); mDialog = null; ); / 设置取消按钮,固定用法声明第二个按钮要用setNegativeButton builder.setNegativeButton(cancel, new DialogInterface.OnClickListener() public void onClick(DialogInterface dialog, int which) / 如果取消被点击 if (listenerNo != null) listenerNo.onCancelClick(); mDialo
23、g = null; ); / 控制这个dialog可不可以按返回键,true为可以,false为不可以 builder.setCancelable(false); / 显示dialog mDialog = builder.create(); if (!mDialog.isShowing() mDialog.show(); public static void showDialog(Context context, int ok, int cancel, int title, int content, final OnOkClickListener listenerYes, final OnCa
24、ncelClickListener listenerNo) showDialog(context, context.getString(ok), context.getString(cancel), context.getString(title), context.getString(content), listenerYes, listenerNo); static ProgressDialog progressDlg = null; /* * 启动进度条 * * param strMessage 进度条显示的信息 * param / 当前的activity */ public stati
25、c void showProgressDlg(Context ctx, String strMessage) if (null = progressDlg) if (ctx = null) return; progressDlg = new ProgressDialog(ctx); /设置进度条样式 progressDlg.setProgressStyle(ProgressDialog.STYLE_SPINNER); /提示的消息 progressDlg.setMessage(strMessage); progressDlg.setIndeterminate(false); progressD
26、lg.setCancelable(true); progressDlg.show(); public static void showProgressDlg(Context ctx) showProgressDlg(ctx, ); /* * 结束进度条 */ public static void stopProgressDlg() if (null != progressDlg & progressDlg.isShowing() progressDlg.dismiss(); progressDlg = null; if (null != dialog & dialog.isShowing()
27、dialog.dismiss(); dialog = null; private static Dialog dialog; public static void showDialogForLoading(Context context, String msg, boolean cancelable) if (null = dialog) if (null = context) return; View view = LayoutInflater.from(context).inflate(R.layout.layout_loading_dialog, null); TextView load
28、ingText = (TextView)view.findViewById(R.id.loading_tip_text); loadingText.setText(msg); dialog = new Dialog(context, R.style.loading_dialog_style); dialog.setCancelable(cancelable); dialog.setCanceledOnTouchOutside(cancelable); dialog.setContentView(iew, new LinearLayout.LayoutParams(LinearLayout.La
29、youtParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT); Activity activity = (Activity) context; if (activity.isFinishing() return; dialog.show(); 可能本博客也不是最好的解决方案,如果有更好的想法,我愿与你互相交流!分享: Retrofit+RxJava错误预处理看到bobo_wang的文章,不仅感觉有受益匪浅,这里做下介绍。首先定义如下Transformer转换器。public static Observable.TransformerResponse, T sTransformer() return responseObservable - responseObservable.map(tResponse - if (!tResponse.success) throw new RuntimeExceptio
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