ApplicationContextAware接口的实战应用

一 需求

系统要求导入报文数据，通过excel的形式，将数据导入系统，报文分为三种报文。

二 分析

报文分为3种，且报文的格式都是excel，报文可以作为一个抽象，并使用模板方法模式进行导入

三 实践

1. 新建抽象类IExcelOutYard

    public interface IExcelOutYard {
   
        String messageType();
   
        void loadExcel(Exchange exchange, String fileName, String camelFileParent);
    }

2. 新建抽象类ExcelOutYardAbstract实现IExcelOutYard

   @Service
   public abstract class ExcelOutYardAbstract implements IExcelOutYard {
   
       private static Logger logger = LogManager.getCurrentClassLogger();
   
       @Override
       public void loadExcel(Exchange exchange, String fileName,String camelFileParent) {
           Object body = exchange.getIn().getBody();
           GenericFile<File> genericFile = (GenericFile<File>) body;
           File file = genericFile.getFile();
           this.analysis(file, fileName,camelFileParent);
       }
   
       private void analysis(File file, String fileName,String camelFileParent) {
           Workbook workbook = getWorkbook(file);
           Sheet sheet = workbook.getSheetAt(0);
           Set<String> messages = Sets.newConcurrentHashSet();
           // 1.校验数据
           validateMessage(sheet, messages, fileName);
           if (ObjectUtils.isNotEmpty(messages)) {
               logger.error("校验不通过,原因[{}]", Joiner.on(";").join(messages));
           }
           // 2 组装对象
           List<Booking> bookings = contrustData(sheet, fileName,camelFileParent);
           // 3 插入数据
           saveAndUpdateData(bookings);
       }

            public List<Booking> contrustData(Sheet sheet, String fileName,String camelFileParent) {
                return null;
            }

            public void saveAndUpdateData(List<Booking> bookings) {
            }

            public void validateMessage(Sheet sheet, Set<String> messages, String fileName) {
            }

            private Workbook getWorkbook(File file) {
             -----
            }


            }
            ```
    3. 新建`ExcelOutYardAccessGate`,`ExcelOutYardEmpty`,`ExcelOutYardSo`继承抽象类`ExcelOutYardAbstract`

        ```
        @Service
        public class ExcelOutYardSo extends ExcelOutYardAbstract {


            @Override
            public String messageType() {
                return ExcelOutYardEnum.OUT_YARD_SO.name();
            }
        ```
    
    4. 新建`ExcelOutYardManager` 实现`ApplicationContextAware`接口
    
        ```
        public class ExcelOutYardManager implements ApplicationContextAware {

            Map<String,IExcelOutYard> excelOutYardMap;

            private Map<String, IExcelOutYard> getExcelOutYard() {
                if (excelOutYardMap == null) {
                    excelOutYardMap = new HashMap<String, IExcelOutYard>();
                }
                return excelOutYardMap;
            }

            public IExcelOutYard getImpleService(String messageType){
                return excelOutYardMap.get(messageType);
            }

            @Override
            public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
                Map<String, IExcelOutYard> beansOfType = applicationContext.getBeansOfType(IExcelOutYard.class);
                this.getExcelOutYard();
                for (IExcelOutYard iExcelOutYard:beansOfType.values()) {
                    excelOutYardMap.put(iExcelOutYard.messageType(),iExcelOutYard);
                }
            }
        }
        ```

5.调用

 String messageType = (String) exchange.getProperty("messageType");
 excelOutYardManager.getImpleService(messageType).loadExcel(exchange, fileName,camelFileParent);

三 结语

ApplicationContextAware接口在我前面的文章中，有所介绍，实现ApplicationContextAware接口后我们可以获得Bean容器中的所有bean，然后我们通过抽象类和他的实现，进行类型的映射，最终调用的时候，只需要传入类型码就可以了，从而实现了一个符合单一职责和开闭原则的设计。