Android--Retrofit2执行多个请求任务并行，任务结束后执行统一输出结果

场景：后端上传文件接口只支持单个文件上传，而业务需求一次性上传多个图片，因此需要多个上传任务并发进行，拿到所有的返回结果后，才能进行下一个流程。

1、使用Java并发工具

private List<Response<JSONObject>> responses = new ArrayList<>();private int requestCount = 0;private void submitTest() {for (LocalMedia localMedia : mSelectList) {uploadImage(new File(localMedia.getPath()));}}private void uploadImage(File file) {JSONObject data = new JSONObject();data.put("file",file);RequestBody imageBody = RequestBody.create(MediaType.parse("multipart/form-data"), file);MultipartBody.Part part = MultipartBody.Part.createFormData("file", file.getName(), imageBody);HttpApi api= RetrofitManager.initRetrofit(RetrofitManager.url_fms).create(HttpApi.class);Call<JSONObject> resultcall = api.up_file("e2e5198e198c78cb59cebfadc592aa45", part);resultcall.enqueue(new Callback<JSONObject>() {//请求成功时回调@Overridepublic void onResponse(Call<JSONObject> call, Response<JSONObject> response) {if(response.isSuccessful()){JSONObject json = response.body();if(json.getBoolean("flag")){responses.add(response);handleResponse();}else{XToastUtils.error(json.getString("message"));}}else {XToastUtils.error(response.message()+"");}}//请求失败时候的回调@Overridepublic void onFailure(Call<JSONObject> call, Throwable throwable) {XToastUtils.error(throwable.getMessage()+"");}});}private synchronized void handleResponse() {requestCount++;if (requestCount == mSelectList.size()) {// 所有请求都已完成，可以在这里处理合并的结果handleCombinedResponse(responses);}}/*** 处理合并的结果*/private void handleCombinedResponse(List<Response<JSONObject>> responses) {List<String> result = new ArrayList<>();for (Response<JSONObject> response : responses){if(response.isSuccessful()){JSONObject json = response.body();if(json.getBoolean("flag")){XToastUtils.success(json.getString("message"));result.add(json.getString("data"));}else{XToastUtils.error(json.getString("message"));}}else {XToastUtils.error(response.message()+"");}}System.out.println(result);}

以上使用了synchronized关键字来确保在多线程环境中handleResponse()方法能够正确地计数并处理响应。

运行结果：

2.使用CompletableFuture来实现

public String performParallelRequests() {List<CompletableFuture<String>> futures = new ArrayList<>();for (LocalMedia localMedia : mSelectList) {File file = new File(localMedia.getPath());CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {try {// 执行第一个请求JSONObject data = new JSONObject();data.put("file",file);RequestBody imageBody = RequestBody.create(MediaType.parse("multipart/form-data"), file);MultipartBody.Part part = MultipartBody.Part.createFormData("file", file.getName(), imageBody);HttpApi api= RetrofitManager.initRetrofit(RetrofitManager.url_fms).create(HttpApi.class);Call<JSONObject> resultcall = api.up_file("e2e5198e198c78cb59cebfadc592aa45", part);Response<JSONObject> execute = resultcall.execute();if(execute.isSuccessful()){return execute.body().getString("data");}} catch (IOException e) {e.printStackTrace();}return null;});futures.add(future);}List<String> results = new ArrayList<>();CompletableFuture<Void> allOf = CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]));try {allOf.get();for (CompletableFuture<String> future : futures) {String result = future.get();results.add(result);System.out.println(result);}System.out.println("results---------"+results);} catch (ExecutionException e) {throw new RuntimeException(e);} catch (InterruptedException e) {throw new RuntimeException(e);}return null;}

运行结果：