http传输大文件

有时我们需要传输的文件超过了机器内存限制,如果使用传统的方式将整个文件读到字节数组再通过http方式发送,显然是不行的。此时我们可以使用如下几种方式

1 长连接+分块

使用http1.1的新特性:长连接和分块传输

长连接:HTTP连接通常保持连接状态,直到所有数据块都被发送完毕。它允许在同一个TCP连接上发送和接收多个HTTP请求/响应,而不是每个请求/响应都打开一个新的连接

分块传输:分块上传(Chunked Transfer Encoding)是HTTP/1.1协议中定义的一种数据传输机制,它允许客户端在不知道内容总大小的情况下,将数据分成一系列的块(chunks)进行发送。这种机制特别适用于发送大文件或者数据流,因为它允许服务器开始处理数据,而不必等待所有数据都被发送完毕。

请求示例

POST /upload HTTP/1.1 //请求行
Host: example.com //请求头
Transfer-Encoding: chunked //请求头,这里标志了使用分块机制并指定了编码方式
Content-Type: application/octet-stream //请求头
Connection: keep-alive //请求头

1A\r\n //下面是请求体,这里有两个块。每个块第一行标志块大小,然后回车携带本块内容
This is the first chunk of data.\r\n
B\r\n
And this is the second chunk.\r\n
0\r\n //结束标志,发送一个空的块
\r\n

通常,分块传输要结合长连接一起使用,这样有助于提高传输效率。但是长连接不是绝对的。当不使用长连接而只是用分块时,请求发出后,只会传输第一个块。接着会再建立tcp连接发送第二个块。

代码示例

调用方

    public void upload(String localFile) {
        String targetUrl = "http://xxx:8080/binary-upload/upload";
        File file = new File(localFile);

        try {
            FileInputStream fileInputStream = new FileInputStream(file);
            URL url = new URL(targetUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();

            // Enable input and output streams
            connection.setDoInput(true);
            connection.setDoOutput(true);

            // Disable caching
            connection.setUseCaches(false);

            // Set HTTP request headers
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Connection", "Keep-Alive");
            connection.setRequestProperty("Cache-Control", "no-cache");
            connection.setRequestProperty("Content-Type", "application/octet-stream");
            connection.setRequestProperty("Transfer-Encoding", "chunked");
            connection.setRequestProperty("fileName", file.getName());// Set ChunkedStreamingMode to avoid OutOfMemoryError for large files
            connection.setChunkedStreamingMode(1024);

            // Open output stream
            DataOutputStream outputStream = new DataOutputStream(connection.getOutputStream());

            // Write file data in chunks
            byte[] buffer = new byte[1024*1024];
            int bytesRead;
//            int i=0;
            while ((bytesRead = fileInputStream.read(buffer)) != -1) {
//                LOGGER.info("bytesRead:"+i++);
                outputStream.write(buffer, 0, bytesRead);
            }

            // Flush output stream
            outputStream.flush();
            outputStream.close();
            fileInputStream.close();


            // Check server's response
            int responseCode = connection.getResponseCode();
            System.out.println("Server's response code: " + responseCode);

            // Close the connection
            connection.disconnect();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

上传文件调用的接口

@RestController
@RequestMapping("/binary-upload")
public class BinaryUploadController {
    private static final Logger LOGGER = LoggerFactory.getLogger(BinaryUploadController.class);


    @PostMapping("/upload")
    public Object upload(HttpServletRequest request) {
        String fileName = request.getHeader("fileName");
        LOGGER.info("upload");
        // 设置文件的存储路径
        String storagePath = "e:/"+fileName;

        // 使用try-with-resources确保资源正确关闭
        try (InputStream inputStream = request.getInputStream();
             // 打开文件输出流,设置为追加模式
             FileOutputStream fileOutputStream = new FileOutputStream(storagePath, true);
             BufferedOutputStream outputStream = new BufferedOutputStream(fileOutputStream)) {

            byte[] buffer = new byte[1024*1024];
            int i = 0;
            int bytesRead;
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                if(i++%1000==0) {
                    LOGGER.info("写:{}", i);
                }
                outputStream.write(buffer, 0, bytesRead);
            }
            // 确保所有数据都写入文件
            outputStream.flush();
            return new ResponseEntity<>("File uploaded and appended successfully.", HttpStatus.OK);
        } catch (IOException e) {
            e.printStackTrace();
            return new ResponseEntity<>("Error uploading file.", HttpStatus.INTERNAL_SERVER_ERROR);
        }
    }

}

经过实测,上传速度还是可以的,20G文件大约5分钟。

但是,这里是本地通过java api凤凰http请求调用/binary-upload接口,也就是说要求本地要有一个上传工具,帮我们实现封装请求参数(比如设置请求头Transfer-Encoding chunked)等动作。

 

posted @ 2024-04-08 14:35  zhenjingcool  阅读(638)  评论(0编辑  收藏  举报