web项目使用多线程上传文件

在Web项目中，文件上传通常是一个耗时的操作，因此使用多线程可以提高上传速度和用户体验。以下是使用Java Servlet和多线程实现文件上传的示例代码：

@WebServlet("/upload")
@MultipartConfig
public class FileUploadServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Collection<Part> parts = request.getParts();
        for (Part part : parts) {
            if (part.getHeader("Content-Disposition").contains("filename")) {
                String fileName = extractFileName(part);
                FileUploadThread fileUploadThread = new FileUploadThread(part, fileName);
                fileUploadThread.start();
            }
        }
        response.getWriter().println("Upload started successfully.");
    }

    private String extractFileName(Part part) {
        String contentDisp = part.getHeader("Content-Disposition");
        String[] items = contentDisp.split(";");
        for (String s : items) {
            if (s.trim().startsWith("filename")) {
                return s.substring(s.indexOf("=") + 2, s.length() - 1);
            }
        }
        return "";
    }

    private class FileUploadThread extends Thread {
        private Part part;
        private String fileName;

        public FileUploadThread(Part part, String fileName) {
            this.part = part;
            this.fileName = fileName;
        }

        public void run() {
            try (InputStream inputStream = part.getInputStream()) {
                // Save the file to disk or upload to a remote server
                // ...
                System.out.println(fileName + " uploaded successfully.");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

该示例代码使用了Java Servlet的`@MultipartConfig`注解来支持文件上传，并通过多线程处理每个文件上传。当一个文件上传时，会创建一个`FileUploadThread`线程来处理该文件，从而实现多线程上传。