java下载文件流，不生成中间文件。

代码设计：

从前端获取的数据经过后端加工后，生成文件流，并返回前端，（不生成中间文件，注意内存，记得关闭流）

代码实现

    @ApiOperation(value = "下载文件", notes = "")@PostMapping("/getDownLoadScriptFile")public void getDownLoadScriptFile(@RequestBody ParamsObject vo, HttpServletRequest request, HttpServletResponse response) throws Exception {SysUserEntityVo uc = (SysUserEntityVo) request.getAttribute("UC");gClientScriptService.getDownLoadScriptFile(vo, uc,response);}

  @Overridepublic void getDownLoadScriptFile(ParamsObject vo, SysUserEntityVo uc, HttpServletResponse response) throws Exception {String fileContent = vo.getFileContent();String fileName = vo.getFileName();String encodeFileName = URLEncoder.encode(fileName);ServletOutputStream out = response.getOutputStream();try {//设置允许跨域的keyresponse.setHeader("Access-Control-Expose-Headers", "Content-Disposition");//文件名有“，”等特殊字符发送到前端会报错，用""括起来解决response.addHeader("Content-Disposition", "attachment;filename=\"" + encodeFileName + "\"");//设置文件大小response.addHeader("Content-Length", "" + fileContent.getBytes().length);//设置文件名，避免问题，这个也用""括起来response.setHeader("filename,", "filename=\"" + encodeFileName + "\"");//设置文件类型response.setContentType("application/octet-stream");out.write(fileContent.getBytes(StandardCharsets.UTF_8));out.flush();} catch (Exception e) {throw e;} finally {try {out.close();} catch (Exception e) {throw e;}try {out.close();} catch (Exception e) {throw e;}}}