JAVA檔案下載

1、控制器程式碼

@PostMapping('/clientDownload')
    public void clientDownload(HttpServletResponse response){
        try {
            return FileUtils.downloadFile(filePath,downloadnFileName,response);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    
    @PostMapping('/download')
    public ResponseEntity<InputStreamResource> download(@RequestParam Integer id){
        try {
            return FileUtils.fileDownload(new File(file.getFilePath()),file.getFileName());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

2、檔案下載工具類FileUtils.java

 /**
     * @description: 直接下載檔案
     * @date: 2024/11/30 16:28
     * @param file
     * @param downloadFileName
     * @return org.springframework.http.ResponseEntity<org.springframework.core.io.InputStreamResource>
     */
    public static ResponseEntity<InputStreamResource> fileDownload(File file, String downloadFileName) {
        InputStream is;
        InputStreamResource resource;
        try {
            String fileName = StringUtils.isNotBlank(downloadFileName) ? downloadFileName : file.getName();
            fileName = URLEncoder.encode(fileName,'UTF-8');
            is = new FileInputStream(file);
            resource = new InputStreamResource(is);
            HttpHeaders headers = new HttpHeaders();
            headers.add('Content-Disposition', 'attachment; filename=\'' + fileName + '\'');
            headers.add('Cache-Control', 'no-cache, no-store, must-revalidate');
            headers.add('Pragma', 'no-cache');
            headers.add('Expires', '0');
            return ResponseEntity.ok()
                    .headers(headers)
                    .contentLength(is.available())
                    .contentType(MediaType.parseMediaType('application/octet-stream'))
                    .body(resource);
        } catch (IOException e) {
            String errMsg = '檔案下載異常:' + e.toString();
            log.info(errMsg);
            throw new DTOCheckException(errMsg);
        }
    }


    /**
     * @description: 以流的形式下載檔案
     * @date: 2024/11/30 17:29
     * @param path
     * @param downloadFileName
     * @param response
     * @return javax.servlet.http.HttpServletResponse
     */
    public static HttpServletResponse downloadFile(String path,String downloadFileName, HttpServletResponse response) {
        try {
            File file = new File(path);
            String fileName = StringUtils.isNotBlank(downloadFileName) ? downloadFileName : file.getName();
            fileName = URLEncoder.encode(fileName,'UTF-8');
            // 以流的形式下載檔案
            InputStream fis = new BufferedInputStream(new FileInputStream(path));
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            fis.close();
            // 清空response
            response.reset();
            // 設定response的Header
            response.addHeader('Content-Disposition', 'attachment;filename=' + fileName);
            response.addHeader('Content-Length', '' + file.length());
            OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
            response.setContentType('application/octet-stream');
            toClient.write(buffer);
            toClient.flush();
            toClient.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        return response;
    }