将 byte[] 转换为 MultipartFile

Question

我想创建一个 Excel 文件，将此文件转换为 MultipartFile.class，因为我已测试读取文件 MultipartFile，我创建了我的文件，但我不知道将 byte[] 转换为 MultipartFile，因为我的函数读取 MultipartFile。

        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;

错误：

Cannot cast from byte[] to MultipartFile

Answer 1

MultipartFile 是一个接口，因此请提供您自己的实现并包装您的字节数组。

使用下面的类 -

public class BASE64DecodedMultipartFile implements MultipartFile {
        private final byte[] imgContent;

        public BASE64DecodedMultipartFile(byte[] imgContent) {
            this.imgContent = imgContent;
        }

        @Override
        public String getName() {
            // TODO - implementation depends on your requirements 
            return null;
        }

        @Override
        public String getOriginalFilename() {
            // TODO - implementation depends on your requirements
            return null;
        }

        @Override
        public String getContentType() {
            // TODO - implementation depends on your requirements
            return null;
        }

        @Override
        public boolean isEmpty() {
            return imgContent == null || imgContent.length == 0;
        }

        @Override
        public long getSize() {
            return imgContent.length;
        }

        @Override
        public byte[] getBytes() throws IOException {
            return imgContent;
        }

        @Override
        public InputStream getInputStream() throws IOException {
            return new ByteArrayInputStream(imgContent);
        }

        @Override
        public void transferTo(File dest) throws IOException, IllegalStateException { 
            new FileOutputStream(dest).write(imgContent);
        }
    }