java - 如何实现基于Key的CsvProcessing工厂设计模式

Question

我已经编写了一个 Controller ，它是MototuploadService(用于电机上传)的默认 Controller ，但我需要制作一个工厂设计，以便基于parentPkId，需要调用HealUploadService、TempUploadService、PersonalUploadService等，这些服务将有单独的文件处理阶段。

controller is below.

@RequestMapping(value = "/csvUpload", method = RequestMethod.POST)
    public List<String> csvUpload(@RequestParam String parentPkId, @RequestParam List<MultipartFile> files)
            throws IOException, InterruptedException, ExecutionException, TimeoutException {
        log.info("Entered method csvUpload() of DaoController.class");
        List<String> response = new ArrayList<String>();
        ExecutorService executor = Executors.newFixedThreadPool(10);
        CompletionService<String> compService = new ExecutorCompletionService<String>(executor);
        List< Future<String> > futureList = new ArrayList<Future<String>>();
        for (MultipartFile f : files) {
            compService.submit(new ProcessMutlipartFile(f ,parentPkId,uploadService));
            futureList.add(compService.take());
        }       
        for (Future<String> f : futureList) {
            long timeout = 0;
            System.out.println(f.get(timeout, TimeUnit.SECONDS));
            response.add(f.get());
        }
        executor.shutdown();
        return response;
    }

这里是ProcessMutlipartFile类，它扩展了可调用接口(interface)，CompletionService的compService.submit()调用该类，该类又执行call() code> 方法，它将处理一个文件。

public class ProcessMutlipartFile implements Callable<String>
{
   private MultipartFile file; 
   private String temp;
   private MotorUploadService motUploadService;
   public ProcessMutlipartFile(MultipartFile file,String temp, MotorUploadService motUploadService )
   {
       this.file=file;
       this.temp=temp;
       this.motUploadService=motUploadService;
   }

   public String call() throws Exception 
   {

    return   motUploadService.csvUpload(temp, file);
    }

}

下面是 MotorUploadService 类，我在其中逐行处理上传的 CSV 文件，然后调用 validateCsvData() 方法来验证数据，它返回具有行号和与其关联的错误的 ErrorObject。如果 csvErrorRecords 为 null，则没有错误并继续保存到 Db。否则将 errorList 保存到数据库并返回上传失败。

@Component
public class MotorUploadService {

@Value("${external.resource.folder}")
     String resourceFolder;

    public String csvUpload(String parentPkId, MultipartFile file) {

    String OUT_PATH = resourceFolder;

    try {
            DateFormat df = new SimpleDateFormat("yyyyMMddhhmmss"); 
            String filename = file.getOriginalFilename().split(".")[0] + df.format(new Date()) + file.getOriginalFilename().split(".")[1];
            Path  path = Paths.get(OUT_PATH,fileName)
            Files.copy(file.getInputStream(), path, StandardCopyOption.REPLACE_EXISTING);
        }
        catch(IOException e){
            e.printStackTrace();
            return "Failed to Upload File...try Again";
        }
        List<TxnMpMotSlaveRaw> txnMpMotSlvRawlist = new ArrayList<TxnMpMotSlaveRaw>();

        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(file.getInputStream()));
            String line = "";
            int header = 0;
            int lineNum = 1;
            TxnMpSlaveErrorNew txnMpSlaveErrorNew = new TxnMpSlaveErrorNew();
            List<CSVErrorRecords> errList = new ArrayList<CSVErrorRecords>();
            while ((line = br.readLine()) != null) {
                // TO SKIP HEADER
                if (header == 0) {
                    header++;
                    continue;
                }
                lineNum++;
                header++;
                // Use Comma As Separator
                String[] csvDataSet = line.split(",");

                CSVErrorRecords csvErrorRecords = validateCsvData(lineNum, csvDataSet);
                System.out.println("Errors from csvErrorRecords is " + csvErrorRecords);

                if (csvErrorRecords.equals(null) || csvErrorRecords.getRecordNo() == 0) {
                    //Function to Save to Db

                } else {
                    // add to errList
                    continue;
                }
            }
            if (txnMpSlaveErrorNew.getErrRecord().size() == 0) {
                //save all
                return "Successfully Uploaded " + file.getOriginalFilename();   
            } 
            else {
                // save the error in db;
                return "Failure as it contains Faulty Information" + file.getOriginalFilename();
            }
        } catch (IOException ex) {
            ex.printStackTrace();
            return "Failure Uploaded " + file.getOriginalFilename();
        }

    }

    private TxnMpMotSlaveRaw saveCsvData(String[] csvDataSet, String parentPkId) {
        /*
            Mapping csvDataSet to PoJo
            returning Mapped Pojo;
        */
    }

    private CSVErrorRecords validateCsvData(int lineNum, String[] csvDataSet) {
        /*
        Logic for Validation goes here
        */
    }

}

如何将其作为 Controller 的工厂设计模式，所以如果

 parentPkId='Motor' call MotorUploadService,
    parentPkId='Heal' call HealUploadService 

我不太了解工厂设计模式，请帮助我。提前致谢。

Answer 1

如果我理解这个问题，本质上你会创建一个接口(interface)，然后根据所需的类型返回一个特定的实现。

所以

public interface UploadService {
  void csvUpload(String temp, MultipartFile file) throws IOException;
}

具体实现

public class MotorUploadService implements UploadService
{
  public void csvUpload(String temp, MultipartFile file) {
    ...
  }
}

public class HealUploadService implements UploadService
{
  public void csvUpload(String temp, MultipartFile file) {
    ...
  }
}

然后是一个工厂

public class UploadServiceFactory {
  public UploadService getService(String type) {
    if ("Motor".equals(type)) {
      return new MotorUploadService();
    }
    else if ("Heal".equals(type)) {
      return new HealUploadService();
    }
  }
}

工厂可能会缓存特定的实现。如果合适的话，还可以使用抽象类而不是接口(interface)。

我认为您当前有一个类UploadService，但如果我遵循您的代码，那实际上是MotorUploadService，所以我会将其重命名为特定的。

然后在 Controller 中，大概已经使用了 UploadServiceFactory 的注入(inject)

...
for (MultipartFile f : files) {
  UploadService uploadSrvc = uploadServiceFactory.getService(parentPkId);
  compService.submit(new ProcessMutlipartFile(f ,parentPkId,uploadService));
  futureList.add(compService.take());
} 

因此，在类里面进行一些额外的阅读:

public class ProcessMutlipartFile implements Callable<String>
{
   private MultipartFile file; 
   private String temp;
   private UploadService uploadService;

   // change to take the interface UploadService
   public ProcessMutlipartFile(MultipartFile file,String temp, UploadService uploadService )
   {
       this.file=file;
       this.temp=temp;
       this.uploadService=uploadService;
   }

   public String call() throws Exception 
   {
     return   uploadService.csvUpload(temp, file);
   }
}