背景：云体检系统需要将不同的体检报告上传到fastdfs服务器，体检报告分为 个人健康体检报告、个人职业体检报告、单位团检报告、个人电测听报告……
    原有代码存在的问题：
    报告存储路径没有统一，需要多层if else 判断封装，逻辑处理放在Controller（结构混乱），这个方法274行代码，后期再有其他类型报告，难以扩展，命名更糟糕，就不多说了，下面为处理过的伪代码。

    1.     public ModelVo uploadReport(@Context HttpServletRequest request) throws Exception {
    2.         List<FileItem> fileItemList = getfileItemList(request);
    3.         int type = -1;  //默认为-1啥都不操作 ，0 表示 个人报告 1表示单位报告 2 表示纯音报告 3职业病报告
    4.         for (int i = 0; i < fileItemList.size(); i++) {
    5.                   String filename = readFileItem();
    6.             if (filename.contains("单位")) {
    7.                 type = 1;
    8.                 doSomething()
    9.             } else if (filename.contains("纯音")) {
    10.                 type = 2;
    11.                 doSomething()
    12.             } else if (filename.contains("健康")) {
    13.                 type = 0;
    14.                 doSomething()
    15.             } else if (filename.contains("职业")) {
    16.                 type = 3;
    17.                 doSomething()
    18.             } else {
    19.                 type = 0;
    20.                 doSomething()
    21.             }
    22.            // read Zip and upload report
    23.             String fileId = readZipAndUploadReport(zipFile)
    24.             if (ftype == 2) {
    25.                doSomething()
    26.             } else {
    27.                 generateHtmlReport()
    28.               if(ftype == 1){
    29.                     buildUrl()
    30.                }else if(ftype == 3){
    31.                     buildUrl()
    32.                }else{
    33.                      buildUrl()
    34.                }
    35.                logger.info("电子报告—>"+JSON.toJSONString(map));
    36.                updateReport(map);
    37.                logger.info("生成电子报告成功");        
    38.             }
    39.             saveLog();
    40.         }
    41.     }

    重构的类图：

    ReportUploader.png
    通过文件路径区分上传报告ReportType (枚举类型)类型，获取对应报告上传ReportUploader，将if else 逻辑剥离到ReportType 获取上：

    1. public enum ReportType {
    2.     group, audiometry, occupation, physique;
    4.     public static ReportType getReportType(String itemName) {
    5.         if (StrUtil.containsAny(itemName, "physique")) {
    6.             return ReportType.physique;
    7.         }
    8.         if (StrUtil.containsAny(itemName, "group")) {
    9.             return ReportType.group;
    10.         }
    11.         if (StrUtil.containsAny(itemName, "audioExam")) {
    12.             return ReportType.audiometry;
    13.         }
    14.         if (StrUtil.containsAny(itemName, "occupation")) {
    15.             return ReportType.occupation;
    16.         }
    17.         return ReportType.physique;
    18.     }
    19. }

    ReportUploader 实例获取基于Spring将所有的ReportUploader 实现类存到uploaders对象池中，根据reportType 获取对应的ReportUploader ，代码如下：

    1. @Component
    2. public class UploaderFactory implements InitializingBean, ApplicationContextAware {
    3.     private static final Map<ReportType, ReportUploader> uploaders = new ConcurrentHashMap();
    5.     private ApplicationContext appContext;
    7.     public ReportUploader getUploader(ReportType reportType) {
    8.         return uploaders.get(reportType);
    9.     }
    11.     @Override
    12.     public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    13.         this.appContext = applicationContext;
    14.     }
    16.     @Override
    17.     public void afterPropertiesSet() throws Exception {
    18.         // 将 Spring 容器中所有的 ReportUploader 注册到 uploaders
    19.         appContext.getBeansOfType(ReportUploader.class)
    20.                 .values()
    21.                 .forEach(uploader -> uploaders.put(uploader.getType(), uploader));
    22.     }
    23. }

    报告上传代码：

    1. @Component
    2. public class UploadHandler {
    3.     public static final Logger logger = LoggerFactory.getLogger(UploadHandler.class);
    4.     @Resource
    5.     UploaderFactory uploaderFactory;
    7.     /**
    8.      * @param fileItems
    9.      * @param type
    10.      */
    11.      @Async
    12.     public void uploadReport(List<FileItem> fileItems, String type) {
    13.         if (CollUtil.isEmpty(fileItems)) {
    14.             return;
    15.         }
    16.         for (FileItem item : fileItems) {
    17.             String itemName = item.getName();
    18.             //文件名就是examNum
    19.             if (item.isFormField() || !StrUtil.equalsIgnoreCase(FileUtil.extName(itemName), "zip")) {
    20.                 continue;
    21.             }
    22.             logger.info("itemName:{}", itemName);
    23.             Long examNum = Long.parseLong(FileUtil.mainName(itemName));
    24.             ReportType reportType = ReportType.getReportType(itemName);
    25.             ReportUploader uploader = uploaderFactory.getUploader(reportType);
    26.             Objects.requireNonNull(item, "文件不存在！");
    27.             try {
    28.                 boolean isPdf = StrUtil.equalsIgnoreCase(".pdf", type);
    29.                 Map<String, Object> uploadedUrls = uploader.upload(item, examNum, isPdf);
    30.                 if (CollUtil.isEmpty(uploadedUrls)) {
    31.                     continue;
    32.                 }
    33.                 updateReportUrl(uploadedUrls);
    34.                 saveLog();
    35.             } catch (Exception e) {
    36.                 logger.error("{},{}", e.getMessage(), e);
    37.             }
    38.         }
    39.     }
    40. }

    Spring @Async 无法复用线程池，每次执行都会新建线程池，如果业务频繁，可以改为自定义线程池异步执行。

    题外话：

    用到了Spring 的两个接口：

    1. ApplicationContextAware接口，作用就是将Spring的ApplicationContext 填充到appContext属性。
    1. public interface ApplicationContextAware extends Aware {
    2.     /**
    3.      * Set the ApplicationContext that this object runs in.
    4.      * Normally this call will be used to initialize the object.
    5.      * <p>Invoked after population of normal bean properties but before an init callback such
    6.      * as {@link org.springframework.beans.factory.InitializingBean#afterPropertiesSet()}
    7.      * or a custom init-method. Invoked after {@link ResourceLoaderAware#setResourceLoader},
    8.      * {@link ApplicationEventPublisherAware#setApplicationEventPublisher} and
    9.      * {@link MessageSourceAware}, if applicable.
    10.      * @param applicationContext the ApplicationContext object to be used by this object
    11.      * @throws ApplicationContextException in case of context initialization errors
    12.      * @throws BeansException if thrown by application context methods
    13.      * @see org.springframework.beans.factory.BeanInitializationException
    14.      */
    15.     void setApplicationContext(ApplicationContext applicationContext) throws BeansException;
    17. }
    1. InitializingBean接口，作用就是在实例化UploaderFactory 后填充uploaders属性。
    1. public interface InitializingBean {
    3.     /**
    4.      * Invoked by a BeanFactory after it has set all bean properties supplied
    5.      * (and satisfied BeanFactoryAware and ApplicationContextAware).
    6.      * <p>This method allows the bean instance to perform initialization only
    7.      * possible when all bean properties have been set and to throw an
    8.      * exception in the event of misconfiguration.
    9.      * @throws Exception in the event of misconfiguration (such
    10.      * as failure to set an essential property) or if initialization fails.
    11.      */
    12.     void afterPropertiesSet() throws Exception;
    14. }