Mybatis的mapper文件中的sql语句的修改后自动加载

public class MapperLoader implements DisposableBean, InitializingBean, ApplicationContextAware {

   private ConfigurableApplicationContext context = null;
   private transient String basePackage = null;
   private HashMap<String, String> fileMapping = new HashMap<String, String>();
   private Scanner scanner = null;
   private ScheduledExecutorService service = null;

   @Override
   public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
      this.context = (ConfigurableApplicationContext) applicationContext;

   }

   @Override
   public void afterPropertiesSet() throws Exception {
      try {
         service = Executors.newScheduledThreadPool(1);
         
         // 获取xml所在包
         MapperScannerConfigurer config = context.getBean(MapperScannerConfigurer.class);
         Field field = config.getClass().getDeclaredField("basePackage");
         field.setAccessible(true);
         basePackage = (String) field.get(config);
         
         // 触发文件监听事件
         scanner = new Scanner();
         scanner.scan();

         service.scheduleAtFixedRate(new Task(), 5, 5, TimeUnit.SECONDS);

      } catch (Exception e1) {
         e1.printStackTrace();
      }

   }

   class Task implements Runnable {
      @Override
      public void run() {
         try {
            if (scanner.isChanged()) {
               System.out.println("*Mapper.xml文件改变,重新加载.");
               scanner.reloadXML();
               System.out.println("加载完毕.");
            }
         } catch (Exception e) {
            e.printStackTrace();
         }
      }

   }

   @SuppressWarnings({ "rawtypes" })
   class Scanner {
      
      private String[] basePackages;
      private static final String XML_RESOURCE_PATTERN = "**/*.xml";
      private ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();

      public Scanner() {
         basePackages = StringUtils.tokenizeToStringArray(MapperLoader.this.basePackage,
               ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
      }

      public Resource[] getResource(String basePackage, String pattern) throws IOException {
         String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX
               + ClassUtils.convertClassNameToResourcePath(context.getEnvironment().resolveRequiredPlaceholders(
                     basePackage)) + "/" + pattern;
         Resource[] resources = resourcePatternResolver.getResources(packageSearchPath);
         return resources;
      }

      public void reloadXML() throws Exception {
         SqlSessionFactory factory = context.getBean(SqlSessionFactory.class);
         Configuration configuration = factory.getConfiguration();
         // 移除加载项
         removeConfig(configuration);
         // 重新扫描加载
         for (String basePackage : basePackages) {
            Resource[] resources = getResource(basePackage, XML_RESOURCE_PATTERN);
            if (resources != null) {
               for (int i = 0; i < resources.length; i++) {
                  if (resources[i] == null) {
                     continue;
                  }
                  try {
                     XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(resources[i].getInputStream(),
                           configuration, resources[i].toString(), configuration.getSqlFragments());
                     xmlMapperBuilder.parse();
                  } catch (Exception e) {
                     throw new NestedIOException("Failed to parse mapping resource: '" + resources[i] + "'", e);
                  } finally {
                     ErrorContext.instance().reset();
                  }
               }
            }
         }

      }

      private void removeConfig(Configuration configuration) throws Exception {
         Class<?> classConfig = configuration.getClass();
         clearMap(classConfig, configuration, "mappedStatements");
         clearMap(classConfig, configuration, "caches");
         clearMap(classConfig, configuration, "resultMaps");
         clearMap(classConfig, configuration, "parameterMaps");
         clearMap(classConfig, configuration, "keyGenerators");
         clearMap(classConfig, configuration, "sqlFragments");

         clearSet(classConfig, configuration, "loadedResources");

      }

      private void clearMap(Class<?> classConfig, Configuration configuration, String fieldName) throws Exception {
         Field field = classConfig.getDeclaredField(fieldName);
         field.setAccessible(true);
         Map mapConfig = (Map) field.get(configuration);
         mapConfig.clear();
      }

      private void clearSet(Class<?> classConfig, Configuration configuration, String fieldName) throws Exception {
         Field field = classConfig.getDeclaredField(fieldName);
         field.setAccessible(true);
         Set setConfig = (Set) field.get(configuration);
         setConfig.clear();
      }

      public void scan() throws IOException {
         if (!fileMapping.isEmpty()) {
            return;
         }
         for (String basePackage : basePackages) {
            Resource[] resources = getResource(basePackage, XML_RESOURCE_PATTERN);
            if (resources != null) {
               for (int i = 0; i < resources.length; i++) {
                  String multi_key = getValue(resources[i]);
                  fileMapping.put(resources[i].getFilename(), multi_key);
               }
            }
         }
      }

      private String getValue(Resource resource) throws IOException {
         String contentLength = String.valueOf((resource.contentLength()));
         String lastModified = String.valueOf((resource.lastModified()));
         return new StringBuilder(contentLength).append(lastModified).toString();
      }

      public boolean isChanged() throws IOException {
         boolean isChanged = false;
         for (String basePackage : basePackages) {
            Resource[] resources = getResource(basePackage, XML_RESOURCE_PATTERN);
            if (resources != null) {
               for (int i = 0; i < resources.length; i++) {
                  String name = resources[i].getFilename();
                  String value = fileMapping.get(name);
                  String multi_key = getValue(resources[i]);
                  if (!multi_key.equals(value)) {
                     isChanged = true;
                     fileMapping.put(name, multi_key);
                  }
               }
            }
         }
         return isChanged;
      }
   }

   @Override
   public void destroy() throws Exception {
      if (service != null) {
         service.shutdownNow();
      }
   }

}