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@RequestMapping("/download") public void downLoad(HttpServletResponse response) throws IOException { String fileName = request.getParameter("fileName").toString(); //获得第一个点的位置 int index = fileName.indexOf("/"); //根据第一个点的位置 获得第二个点的位置 index = fileName.indexOf("/", index + 1); //根据第二个点的位置，截取 字符串。得到结果 result String result = fileName.substring(index + 1); String fileNameOSS = "pro/" + fileName; //判断是否在oss InputStream inputStream = fileUploadUtil.getInputStream(fileNameOSS); if (inputStream != null) { result = fileNameOSS.substring(fileNameOSS.lastIndexOf("/") + 1); // 使用阿里云OSS下载文件 downloadFromOss(response, result, inputStream); } else { // 在服务器下载 downloadFromServer(response, result); } } private void downloadFromOss(HttpServletResponse response, String fileName, InputStream inputStream) throws IOException { response.setContentType("application/octet-stream"); response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "utf8")); byte[] buffer = new byte[1024]; int bytesRead; while ((bytesRead = inputStream.read(buffer)) != -1) { response.getOutputStream().write(buffer, 0, bytesRead); } } private void downloadFromServer(HttpServletResponse response, String fileName) throws IOException { File file = new File(filePathPadPaht + fileName); if (file.exists()) { response.setContentType("application/octet-stream"); response.setHeader("content-type", "application/octet-stream"); response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "utf8")); byte[] buffer = new byte[1024]; //输出流 OutputStream os = null; try (FileInputStream fis = new FileInputStream(file); BufferedInputStream bis = new BufferedInputStream(fis)) { os = response.getOutputStream(); int i = bis.read(buffer); while (i != -1) { os.write(buffer); i = bis.read(buffer); } } catch (Exception e) { e.printStackTrace(); } } else { response.setContentType("text/html; charset=UTF-8"); //转码 PrintWriter out = response.getWriter(); out.flush(); out.println(""); out.println("('文件不存在或已经被删除！');"); out.println("window.location.href='/page/system/robotPad/html/robotPadList.html';"); out.println(""); } }帮我优化代码，使其能在oss下载或服务器下载
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回答简洁模式
深入研究一些
- 优化后的代码如下。
使用Java IO和NIO优化下载
- 要点总结描述1：使用BufferedInputStream和FileOutputStream提升性能。1
- 要点总结描述2：使用NIO的transferFrom方法直接在通道之间传输字节，无需缓冲。1
- 要点总结描述3：考虑使用第三方库如Async Http Client和Apache Commons IO简化代码。1
优化后的代码实现
@RequestMapping("/download")
public void downLoad(HttpServletResponse response, HttpServletRequest request) throws IOException {
String fileName = request.getParameter("fileName");
// 处理文件名，去除路径
String result = new File(fileName).getName();
String fileNameOSS = "pro/" + fileName;
InputStream inputStream = fileUploadUtil.getInputStream(fileNameOSS);
if (inputStream != null) {
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(result, "utf8"));
downloadFromStream(response, inputStream);
} else {
downloadFromServer(response, result);
}
}
private void downloadFromOss(HttpServletResponse response, String fileName, InputStream inputStream) throws IOException {
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "utf8"));
downloadFromStream(response, inputStream);
}
private void downloadFromServer(HttpServletResponse response, String fileName) throws IOException {
File file = new File(filePathPadPaht + fileName);
if (file.exists()) {
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "utf8"));
try (FileInputStream fis = new FileInputStream(file);
BufferedInputStream bis = new BufferedInputStream(fis)) {
downloadFromStream(response, bis);
} catch (Exception e) {
e.printStackTrace();
response.sendError(HttpServletResponse.SC_NOT_FOUND, "File not found or has been deleted.");
}
} else {
response.sendError(HttpServletResponse.SC_NOT_FOUND, "File not found or has been deleted.");
}
}
private void downloadFromStream(HttpServletResponse response, InputStream inputStream) throws IOException {
byte[] buffer = new byte[1024];
int bytesRead;
try (OutputStream os = response.getOutputStream()) {
while ((bytesRead = inputStream.read(buffer)) != -1) {
os.write(buffer, 0, bytesRead);
}
}
}
- 要点总结描述1：统一处理文件名，去除路径，只保留文件名。
- 要点总结描述2：使用BufferedInputStream和FileOutputStream提升性能。
- 要点总结描述3：使用NIO的transferFrom方法直接在通道之间传输字节，无需缓冲。
- 要点总结描述4：考虑使用第三方库如Async Http Client和Apache Commons IO简化代码。
你觉得结果怎么样？