controller 层

  @Autowiredprivate DownloadService service;// 触发下载任务@GetMapping(value = "/downloadData")@ResponseBodypublic Result<Object> downloadData(ServletRequest request,@RequestParam(value = "userId",defaultValue = "anonymous") String userId)throws IOException {log.info("---------------downloadData start-------------");String rootDirectory = request.getServletContext().getRealPath("/");log.info("rootDirectory:"+rootDirectory);// 临时放置文件目录Path p = Paths.get(rootDirectory, "temp");if (!p.toFile().exists()) {p.toFile().mkdirs();}this.service.createDownloadingDataTask(userId);return Result.ok();}//@ApiOperation("检测下载进度")@GetMapping(value = "/check4DownloadingData")public Object check4DownloadingData(@RequestParam(value = "userId",defaultValue = "anonymous") String userId) throws IOException {Result<Object> result = this.service.check4DownloadingDataTask(wwId);if(result.isOK()){File file = (File) result.getResult();// 下载成功返回二进制流return getResponseEntity(file,null,false);}
//        ResponseEntity<String> responseEntity = ResponseEntity.ok()
//                .header("Content-Type", "application/json")
//                .body("Hello World");ResponseEntity<String> responseEntity = new ResponseEntity<>(result.getMsg(), HttpStatus.OK);return responseEntity;}

//service 层不贴了，直接上 serviceImpl 实现类

package com.example.demo.service.impl;import com.example.demo.service.COCReportService;
import com.example.demo.utils.Result;
import com.example.demo.utils.databricks.DatabricksTemplate;
import com.example.demo.utils.poi.render.coc.COCExcelRender;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.io.File;
import java.nio.file.Path;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;@Service
@Slf4j
public class DownloadServiceImpl implements DownloadService {/*** 针对 coc 导出过程数据的文件缓存* Map<String,File> => Map<userId,File>*/private static Map<String,Future<File>>  cache_files = new HashMap<>();@Overridepublic Future<File> createDownloadingDataTask(String userId) {Callable<File> callable = new DownloadingDataTask(userId);FutureTask<File> task = new FutureTask<File>(callable);// 开始执行new Thread(task).start();// 保存凭证cache_files.put(wwId,task);return task;}private static class DownloadingDataTask implements Callable<File>{private String userId;public COCDownloadingDataTask(String userId) {this.userId = userId;}@Overridepublic File call() throws Exception {log.info("---------------downloadData start 2 Render.... -------------");File file = null;try{// 根据自己的业务逻辑，生成 filefile =new File("");log.info("###------------the excel file address:"+file.getAbsolutePath());return file;}catch (Throwable e){log.info(e.getMessage());return null;}}}@Overridepublic Result<Object> check4DownloadingDataTask(String userId) {Future<File> future=  cache_files.get(wwId);if(future==null){return Result.failed("当前用户不存在下载任务，无数据文件下载。");}if(!future.isDone()){return Result.failed("数据文件生成中…请等待1分钟后，点击”回车“确认状态。");}try {return Result.ok(future.get());} catch (Exception e) {log.error(e.getMessage());return Result.failed("任务执行异常，请联系管理员查看日志。");}}
}