REST Api 使用多线程处理 Spring 引导中的文件

Question

他们有什么办法让我可以利用多线程概念并行调用执行并使创建的 @RestController 的执行速度更快，它将接受 String 和 List<MultipartFile>作为请求参数，并且代码正在运行 fine.Problem 这里是如果我通过 for 循环一个接一个地解析一个文件。执行所花费的时间更多。

Below is Controller

@RequestMapping(value = "/csvUpload", method = RequestMethod.POST)
    public List<String> csvUpload(@RequestParam String parentPkId, @RequestParam List<MultipartFile> file)
            throws IOException {
        log.info("Entered method csvUpload() of DaoController.class");
        List<String> response = new ArrayList<String>();
        String temp = parentPkId.replaceAll("[-+.^:,]", "");
        for (MultipartFile f : file) {
            String resp = uploadService.csvUpload(temp, f);
            response.add(resp);
        }
        return response;
    }

我在控制器中调用 uploadService.csvUpload() 方法，在使用 For 循环时一个接一个地解析文件。

下面是我的上传服务Class

public String csvUpload(String parentPkId, MultipartFile file) {
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(file.getInputStream()));
            String line = "";
            int header = 0;
            while ((line = br.readLine()) != null) {
                // TO SKIP HEADER
                if(header == 0) {
                    header++;  
                    continue;
                }
                header++;
                //Use Comma As Separator
                String[] csvDataSet = line.split(",");
                //Saving it to DB

        }catch(IOException ex) {
            ex.printStackTrace();
        }
        return "Successfully Uploaded "+ file.getOriginalFilename();
    }

How to make this Controller as a Multithreaded so that processing is parallel and fast. I'm new to Multithreading and I tried by making use of Callable interface but the Call() method will not take parameters.

欢迎任何线索和建议，在此先感谢。

Answer 1

您需要创建一个 Class，它将实现如下所示的可调用并将期货存储在列表中，最后按如下方式处理期货

public class ProcessMutlipartFile implements Callable<String>
{
   private Mutlipartfile file; 
   private String temp;
   private UploadService uploadService;
   public ProcessMutlipartFile(Mutlipartfile file,String temp, UploadService uploadService )
   {
       this.file=file;
       this.temp=temp,
       this.uploadService=uploadService;
   }

   public String call() throws Exception 
   {

    return   uploadService.csvUpload(temp, file);
    }

 }

在你的控制器中创建一个未来对象列表

 ExecutorService executor = Executors.newFixedThreadPool(10)
List< Future<String> > futureList = new ArrayList<Future<String>>();
     .
     .
     .
         for (MultipartFile f : file) {
                    futureList.add(executor.submit(new ProcessMutlipartFile(file ,temp,uploadService));
                }

终于在您的控制器中

 for (Future f :futureList)
 {
  response.add(f.get());
  }

//shuttingdown the Executor
executor.shutdown();

希望这对您有所帮助

Answer 2

您可以使用parallel stream

执行上传代码

    List<String> response = file.parallelStream().map(f -> uploadService.csvUpload(temp, f))
    .collect(Collectors.toList());

You can execute streams in serial or in parallel. When a stream executes in parallel, the Java runtime partitions the stream into multiple substreams. Aggregate operations iterate over and process these substreams in parallel and then combine the results.

REST Api 使用多线程处理 Spring 引导中的文件

REST Api with Multithreading for handling Files in Spring Boot

java

multithreading

threadpool

spring-boot