Spring boot 实现分片上传到服务器

Spring Boot可以使用Apache Commons FileUpload库实现文件分片上传到服务器。以下是一个简单的实现步骤：

1.在pom.xml文件中添加以下依赖项：

<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.3</version>
</dependency>

2.创建一个控制器类来处理上传请求：

@RestController
@RequestMapping("/upload")
public class FileUploadController {

    @PostMapping("/chunk")
    public ResponseEntity<?> uploadChunk(@RequestParam("file") MultipartFile file,
                                         @RequestParam("chunkIndex") int chunkIndex,
                                         @RequestParam("totalChunks") int totalChunks,
                                         @RequestParam("fileName") String fileName) throws IOException {

        // 在服务器上保存上传的文件块
        saveChunk(file, fileName, chunkIndex);

        // 如果所有块都已上传，则将它们合并成单个文件
        if (chunkIndex == totalChunks - 1) {
            mergeChunks(fileName, totalChunks);
        }

        return ResponseEntity.ok().build();
    }

    private void saveChunk(MultipartFile file, String fileName, int chunkIndex) throws IOException {
        File chunkDir = getChunkDir(fileName);
        File chunkFile = new File(chunkDir, getChunkName(chunkIndex));
        FileUtils.copyInputStreamToFile(file.getInputStream(), chunkFile);
    }

    private void mergeChunks(String fileName, int totalChunks) throws IOException {
        File chunkDir = getChunkDir(fileName);
        File outputFile = new File(getUploadDir(), fileName);
        FileOutputStream outputStream = new FileOutputStream(outputFile, true);

        for (int i = 0; i < totalChunks; i++) {
            File chunkFile = new File(chunkDir, getChunkName(i));
            FileInputStream inputStream = new FileInputStream(chunkFile);
            IOUtils.copy(inputStream, outputStream);
            inputStream.close();
            chunkFile.delete();
        }

        outputStream.close();
        chunkDir.delete();
    }

    private File getChunkDir(String fileName) {
        File chunkDir = new File(getUploadDir(), fileName);
        if (!chunkDir.exists()) {
            chunkDir.mkdir();
        }
        return chunkDir;
    }

    private String getChunkName(int chunkIndex) {
        return String.format("chunk-%d", chunkIndex);
    }

    private File getUploadDir() {
        File uploadDir = new File("uploads");
        if (!uploadDir.exists()) {
            uploadDir.mkdir();
        }
        return uploadDir;
    }
}

3.在前端实现分片上传逻辑，并在每个块上传时调用控制器的endpoints。以下是一个简单的JavaScript实现：

function uploadFile(file) {
    const chunkSize = 1 * 1024 * 1024; // 每个块的大小（1MB）
    const totalSize = file.size; // 文件总大小
    const totalChunks = Math.ceil(totalSize / chunkSize); // 文件总块数
    let uploadedChunks = 0; // 已上传块数

    const uploadChunk = (chunkIndex) => {
        const start = chunkIndex * chunkSize;
        const end = Math.min(start + chunkSize, totalSize);
        const chunk = file.slice(start, end);
        const formData = new FormData();
        formData.append('file', chunk);
        formData.append('chunkIndex', chunkIndex);
        formData.append('totalChunks', totalChunks);
        formData.append('fileName', file.name);

        return fetch('/upload/chunk', {
            method: 'POST',
            body: formData
        }).then(() => {
            uploadedChunks++;

            if (uploadedChunks === totalChunks) {
                console.log('Upload complete');
            } else {
                uploadChunk(uploadedChunks);
            }
        });
    }

    uploadChunk(0);
}

这样，您就可以使用Spring Boot和Apache Commons FileUpload将文件分片上传到服务器了。