通用文件强制下载

通用文件强制下载

后端：

@ApiOperation(
        value = "通用文件下载",
        notes = "通用文件下载"
    )
    @GetMapping({"/view/{id}"})
    public void viewImage(HttpServletResponse response, @PathVariable String id) {
        if (Str.isNotEmpty(id)) {
            SysFile sysFile = (SysFile)this.sysFileService.getById(id);
            if (sysFile != null && Str.isNotEmpty(sysFile.getPath())) {
                String filePath = this.uploadPath + sysFile.getPath();
                this.outputImage(response, filePath, sysFile.getOriginalName());
            }
        }
 
    }
 
    private void outputImage(HttpServletResponse response, String filePath, String fileName) {
        InputStream inputStream = null;
        ServletOutputStream outputStream = null;
 
        try {
            File file = new File(filePath);
            response.setContentType("application/force-download");
            response.addHeader("Content-Disposition", "attachment;fileName=" + new String((Str.isNotEmpty(fileName) ? fileName : file.getName()).getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1));
            inputStream = new BufferedInputStream(new FileInputStream(filePath));
            outputStream = response.getOutputStream();
            byte[] buf = new byte[1024];
 
            int len;
            while((len = inputStream.read(buf)) > 0) {
                outputStream.write(buf, 0, len);
            }
 
            response.flushBuffer();
        } catch (IOException var21) {
            log.error("预览文件失败" + var21.getMessage());
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException var20) {
                    log.error(var20.getMessage(), var20);
                }
            }
 
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException var19) {
                    log.error(var19.getMessage(), var19);
                }
            }
 
        }
    }

前端：

/**
 * 下载文件
 * @param {*} url 
 */
export function XHRLoadFileTwo(url) {
  const token = getToken();
  let xhr = new XMLHttpRequest()
  if (url.charAt(0) !== "/") {
    url = "/" + url;
  }
 
  xhr.open('get', process.env.BASE_API + url)
  //如果需要请求头中这是token信息可以在这设置
  xhr.setRequestHeader('Content-Type', 'application/json;charset=UTF-8')
  xhr.setRequestHeader('X-Access-Token', token)
  xhr.responseType = 'blob'
  xhr.send();
  // 此处引入了mock需要这样写,mock改写了XMLHttpRequest
  if (window._XMLHttpRequest) {
    XHRLoadFileTwo_1(xhr)
  } else {
    xhr.onreadystatechange = function () {
      XHRLoadFileTwo_1(xhr)
    }
  }
}
 
export function XHRLoadFileTwo_1(xhr) {
  if (xhr.readyState === 4 && xhr.status === 200) {
    const blob = xhr.response;
    const filename = getFilename(xhr.getResponseHeader('content-disposition'));
    
    // 创建一个a标签元素，设置下载属性，点击下载，最后移除该元素
    const link = document.createElement('a');
    link.href = window.URL.createObjectURL(blob);
    link.download = filename;
    
    // 下载
    link.click();
    
    // 移除a标签元素
    document.body.removeChild(link);
  }
}
 
export function getFilename(header) {
  const match = header.match(/fileName=(.*?)(;|$)/);
  if (match && match.length > 1) {
    return match[1];
  } else {
    return 'download';
  }
}