大文件上傳一般需要將文件切片（chunk）上傳，然后再將所有切片合并為完整的文件?？梢园匆韵逻壿嬤M行實現(xiàn)：
前端在頁面中選擇要上傳的文件，并使用Blob.slice方法對文件進行切片，一般每個切片大小為固定值（比如5MB），并記錄總共有多少個切片。
將切片分別上傳到后端服務，可以使用XMLHttpRequest或Axios等庫發(fā)送Ajax請求。對于每個切片，需要包含三個參數(shù)：當前切片索引（從0開始）、切片總數(shù)、切片文件數(shù)據(jù)。
后端服務接收到切片后，保存到指定路徑下的臨時文件中，并記錄已上傳的切片索引和上傳狀態(tài)。如果某個切片上傳失敗，則通知前端重傳該切片。
當所有切片都上傳成功后，后端服務讀取所有切片內容并將其合并為完整的文件?？梢允褂胘ava.io.SequenceInputStream和BufferedOutputStream來實現(xiàn)文件合并。
最后返回文件上傳成功的響應結果給前端即可。

前端

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>File Upload</title>
</head>
<body>
    <input type="file" id="fileInput">
    <button onclick="upload()">Upload</button>
    <script>
        function upload() {
            let file = document.getElementById("fileInput").files[0];
            let chunkSize = 5 * 1024 * 1024; // 切片大小為5MB
            let totalChunks = Math.ceil(file.size / chunkSize); // 計算切片總數(shù)
            let index = 0;
            while (index < totalChunks) {
                let chunk = file.slice(index * chunkSize, (index + 1) * chunkSize);
                let formData = new FormData();
                formData.append("file", chunk);
                formData.append("index", index);
                formData.append("totalChunks", totalChunks);
                // 發(fā)送Ajax請求上傳切片
                $.ajax({
                    url: "/uploadChunk",
                    type: "POST",
                    data: formData,
                    processData: false,
                    contentType: false,
                    success: function () {
                        if (++index >= totalChunks) {
                            // 所有切片上傳完成，通知服務端合并文件
                            $.post("/mergeFile", {fileName: file.name}, function () {
                                alert("Upload complete!");
                            })
                        }
                    }
                });
            }
        }
    </script>
</body>
</html>

后端

controller層:

@RestController
public class FileController {

    @Value("${file.upload-path}")
    private String uploadPath;

    @PostMapping("/uploadChunk")
    public void uploadChunk(@RequestParam("file") MultipartFile file,
                            @RequestParam("index") int index,
                            @RequestParam("totalChunks") int totalChunks) throws IOException {
        // 以文件名+切片索引號為文件名保存切片文件
        String fileName = file.getOriginalFilename() + "." + index;
        Path tempFile = Paths.get(uploadPath, fileName);
        Files.write(tempFile, file.getBytes());
        // 記錄上傳狀態(tài)
        String uploadFlag = UUID.randomUUID().toString();
        redisTemplate.opsForList().set("upload:" + fileName, index, uploadFlag);
        // 如果所有切片已上傳，則通知合并文件
        if (isAllChunksUploaded(fileName, totalChunks)) {
            sendMergeRequest(fileName, totalChunks);
        }
    }

    @PostMapping("/mergeFile")
    public void mergeFile(String fileName) throws IOException {
        // 所有切片均已成功上傳，進行文件合并
        List<File> chunkFiles = new ArrayList<>();
        for (int i = 0; i < getTotalChunks(fileName); i++) {
            String chunkFileName = fileName + "." + i;
            Path tempFile = Paths.get(uploadPath, chunkFileName);
            chunkFiles.add(tempFile.toFile());
        }
        Path destFile = Paths.get(uploadPath, fileName);
        try (OutputStream out = Files.newOutputStream(destFile);
             SequenceInputStream seqIn = new SequenceInputStream(Collections.enumeration(chunkFiles));
             BufferedInputStream bufIn = new BufferedInputStream(seqIn)) {
            byte[] buffer = new byte[1024];
            int len;
            while ((len = bufIn.read(buffer)) > 0) {
                out.write(buffer, 0, len);
            }
        }
        // 清理臨時文件和上傳狀態(tài)記錄
        for (int i = 0; i < getTotalChunks(fileName); i++) {
            String chunkFileName = fileName + "." + i;
            Path tempFile = Paths.get(uploadPath, chunkFileName);
            Files.deleteIfExists(tempFile);
            redisTemplate.delete("upload:" + chunkFileName);
        }
    }

    private int getTotalChunks(String fileName) {
        // 根據(jù)文件名獲取總切片數(shù)
        return Objects.requireNonNull(Paths.get(uploadPath, fileName).toFile().listFiles()).length;
    }

    private boolean isAllChunksUploaded(String fileName, int totalChunks) {
        // 判斷所有切片是否已都上傳完成
        List<String> uploadFlags = redisTemplate.opsForList().range("upload:" + fileName, 0, -1);
        return uploadFlags != null && uploadFlags.size() == totalChunks;
    }

    private void sendMergeRequest(String fileName, int totalChunks) {
        // 發(fā)送合并文件請求
        new Thread(() -> {
            try {
                URL url = new URL("http://localhost:8080/mergeFile");
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setRequestMethod("POST");
                conn.setDoOutput(true);
                conn.setDoInput(true);
                conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=utf-8");
                OutputStream out = conn.getOutputStream();
                String query = "fileName=" + fileName;
                out.write(query.getBytes());
                out.flush();
                out.close();
                BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8));
                while (br.readLine() != null) ;
                br.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }).start();
    }

    @Autowired
    private RedisTemplate<String, Object> redisTemplate;
}

其中，file.upload-path為文件上傳的保存路徑，可以在application.properties或application.yml中進行配置。同時需要添加RedisTemplate的Bean以便記錄上傳狀態(tài)。

RedisTemplate配置

如果需要使用RedisTemplate，需要引入下方的包

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

同時在yml配置redis的信息

spring.redis.host=localhost
spring.redis.port=6379
spring.redis.database=0

然后在自己的類中這樣使用

@Component
public class myClass {

? ? @Autowired
? ? private RedisTemplate<String, Object> redisTemplate;

? ? public void set(String key, Object value) {
? ? ? ? redisTemplate.opsForValue().set(key, value);
? ? }

? ? public Object get(String key) {
? ? ? ? return redisTemplate.opsForValue().get(key);
? ? }
}

注意事項