通过controller下载文件

矫情吗；* 2023-06-21 10:16 40阅读 0赞

public void downFile(HttpServletRequest request, HttpServletResponse response, File downFile) { 
            try { 
                String range = null;
                // 特殊头处理
                if (null != request.getHeader("RANGE")) { // 断点续传的头
                    range = request.getHeader("RANGE");
                }
                if (null != request.getHeader("Range")) { 
                    range = request.getHeader("Range");
                }
                response.setContentType("application/x-msdownload");
                int fileLength = Integer.parseInt(Long.toString(downFile.length()));
                response.setContentLength(fileLength);
                response.setHeader("Content-Disposition", "attachment;filename=" + new String(downFile.getName().getBytes("gb2312"), "ISO8859-1"));// 处理默认文件名的中文问题
                int startPos = 0;
                if (null != range) { // 断点续传
                    startPos = Integer.parseInt(range.replaceAll("bytes=", "").replaceAll("-$|-\\d+$", ""));
                }
                if (startPos == 0) { 
                    FileCopyUtils.copy(new FileInputStream(downFile), response.getOutputStream());
                } else { // 断点续传
                    response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
                    if (startPos != 0) { 
                        /** 设置Content-Range: bytes [文件块的开始字节]-[文件的总大小 - 1]/[文件的总大小] **/
                        StringBuffer sb = new StringBuffer("bytes ");
                        sb.append(Long.toString(startPos));
                        sb.append("-");
                        sb.append(Long.toString(fileLength - 1));
                        sb.append("/");
                        sb.append(Long.toString(fileLength));
                        response.setHeader("Content-Range", sb.toString());
                    }
                    if (startPos < fileLength) { 
                        fileLength = fileLength - startPos;
                        response.getOutputStream().write(FileUtils.readFileToByteArray(downFile), (int) startPos, (int) fileLength);
                    }
                }
                response.getOutputStream().flush();
            } catch (Exception e) { 
                e.printStackTrace();
            }
        }