springboot实现文件断点上传代码

Spring Boot 实现文件断点上传可以使用 MultipartFile 类，配合 RandomAccessFile 类和 Range 头部实现。以下是一个简单的示例代码：

@RestController
public class FileController {

    private final String UPLOAD_FOLDER = "/path/to/upload/folder/";

    @PostMapping("/upload")
    public ResponseEntity<?> uploadFile(@RequestParam("file") MultipartFile multipartFile,
                                         @RequestHeader(value = "Range", required = false) String rangeHeader) {

        try {
            File file = new File(UPLOAD_FOLDER + multipartFile.getOriginalFilename());

            // If Range header is present, it means we are resuming an upload
            if (rangeHeader != null) {
                long range = Long.parseLong(rangeHeader.replace("bytes=", "").replace("-", ""));
                RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");
                randomAccessFile.seek(range);
                randomAccessFile.write(multipartFile.getBytes());
                randomAccessFile.close();
            } else {
                multipartFile.transferTo(file);
            }
            return ResponseEntity.ok("File uploaded successfully!");
        } catch (IOException e) {
            e.printStackTrace();
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("Failed to upload file!");
        }
    }
}

在上传文件时，如果请求头中包含 Range 头部，则说明需要断点续传，此时需要使用 RandomAccessFile 类来定位文件指针，并写入上传的文件块。如果 Range 头部不存在，则直接使用 MultipartFile.transferTo() 方法上传整个文件。