文件下载

使用若依框架的springboot项目，接上一篇文件上传后做了下载功能；

1. 前端方法

下面展示一些 下载按钮传id。

actions.push('<a class="btn btn-success btn-xs" onclick="appendixDownLoad(\'' + row.id + '\')"><i class="fa fa-edit"></i>下载</a> ');

访问接口方法：

		//文件下载
        function appendixDownLoad(id) {
            console.log(id)
            const url = prefix + "/appendixDownLoad/" + id;
            window.open(url);
        }

2. 后端方法

    /**
     * 下载【附件】
     * @param id
     * @param response
     * @throws UnsupportedEncodingException
     */
    @GetMapping("/appendixDownLoad/{id}")
    @ResponseBody
    public void appendixDownLoad(@PathVariable("id") String id, HttpServletResponse response) throws UnsupportedEncodingException {
        System.out.println("资源类下载附件，附件ID是："+id);
        TargetAppendix targetAppendix = targetAppendixService.selectTargetAppendixById(id);
        //xxx.png
        String appendixName = targetAppendix.getAppendixName();
        //文件绝对路径
        String filePath = targetAppendix.getAppendixUrl();
        FileDownloadUtil.downloadFile(response, appendixName, filePath);
    }

    /*文件下载*/
    public static void downloadFile(HttpServletResponse response, String fileName, String path){
        if (fileName != null) {
            //设置文件路径
            File file = new File(path);
            if (file.exists()) {
                response.setHeader("content-type", "application/octet-stream");
                response.setContentType("application/octet-stream");
                try {
                    response.setHeader("Content-Disposition", "attachment;filename="+new String(fileName.getBytes("utf-8"),"ISO-8859-1"));
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }
                byte[] buffer = new byte[1024];
                FileInputStream fis = null;
                BufferedInputStream bis = null;
                try {
                    fis = new FileInputStream(file);
                    bis = new BufferedInputStream(fis);
                    OutputStream os = response.getOutputStream();
                    int i = bis.read(buffer);
                    while (i != -1) {
                        os.write(buffer, 0, i);
                        i = bis.read(buffer);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (bis != null) {
                        try {
                            bis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if (fis != null) {
                        try {
                            fis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
    }