perf($POI): close workbook when destroying locale context

spring-cloud-starter/src/main/java/com/jmsoftware/maf/springcloudstarter/controller/AbstractExcelImportController.java

@@ -24,6 +24,7 @@
 import org.springframework.web.multipart.MultipartHttpServletRequest;
 
 import javax.servlet.http.HttpServletRequest;
+import java.io.BufferedInputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
@@ -268,13 +269,31 @@ private void destroyLocaleContext() {
         sheetLocation.remove();
         readingRowCount.remove();
         userDefinedMessage.remove();
+        closeWorkbook(workbook.get());
         workbook.remove();
+        closeWorkbook(workbookWithErrorMessage.get());
         workbookWithErrorMessage.remove();
         excelFilePath.remove();
         exceptionOccurred.remove();
         file.remove();
     }
 
+    /**
+     * Close workbook.
+     *
+     * @param workbook the workbook
+     */
+    private void closeWorkbook(Workbook workbook) {
+        if (workbook != null) {
+            try {
+                workbook.close();
+            } catch (IOException e) {
+                log.error("Exception occurred when closing workbook! Exception message: {}, workbook: {}",
+                          e.getMessage(), workbook);
+            }
+        }
+    }
+
     /**
      * Upload excel file. Any exceptions happened in any lifecycle will not interrupt the whole process.
      *
@@ -577,13 +596,13 @@ public static void main(String[] args) {
     private Workbook readFile(@NonNull File file) throws IOException {
         Workbook workbook = null;
         val extension = FilenameUtils.getExtension(file.getName());
+        val bufferedInputStream = new BufferedInputStream(new FileInputStream(file));
         if (XLS.equals(extension)) {
-            FileInputStream fileInputStream = new FileInputStream(file);
-            POIFSFileSystem poifsFileSystem = new POIFSFileSystem(fileInputStream);
+            POIFSFileSystem poifsFileSystem = new POIFSFileSystem(bufferedInputStream);
             workbook = new HSSFWorkbook(poifsFileSystem);
-            fileInputStream.close();
+            bufferedInputStream.close();
         } else if (XLSX.equals(extension)) {
-            workbook = new XSSFWorkbook(new FileInputStream(file));
+            workbook = new XSSFWorkbook(bufferedInputStream);
         }
         return workbook;
     }