title: Convert byte[] to MultipartFile
body: <p>I want create a File Excel, convert this file to MultipartFile.class because I have test that read files MultipartFile, I created my file, but I don't know transform byte[] to MultipartFile because my function read MultipartFile.</p>
  
  <pre><code>        XSSFWorkbook workbook = new XSSFWorkbook();
          XSSFSheet sheet = workbook.getSheetAt(0);
          XSSFRow row = sheet.createRow((short) 1);
          row.createCell(0).setCellValue("2019");
          row.createCell(1).setCellValue("11");
          row.createCell(2).setCellValue("1");
          row.createCell(3).setCellValue("2");
  
          byte[] fileContent = null; 
          ByteArrayOutputStream bos = null;
  
          bos = new ByteArrayOutputStream();
          workbook.write(bos);
          workbook.close();
          fileContent = bos.toByteArray();
          bos.close();
  
  
          MultipartFile multipart = (MultipartFile) fileContent;
  </code></pre>
  
  <p>err:</p>
  
  <pre><code>Cannot cast from byte[] to MultipartFile
  </code></pre>