写一下springmvc + vue的大文件分片上传代码，分片用MD5加密

好的，下面是SpringMVC和Vue实现大文件分片上传的代码，分片使用MD5加密：

1.前端Vue代码：

<template>
  <div>
    <input type="file" @change="handleFileChange"/>
    <button @click="upload">上传</button>
  </div>
</template>

<script>
export default {
  data () {
    return {
      file: null,
      chunks: [],
      chunkSize: 1024 * 1024 * 2, // 分片大小为2M
      md5: null
    }
  },
  methods: {
    handleFileChange (event) {
      this.file = event.target.files[0]
      this.md5 = null
      this.createChunks()
    },
    createChunks () { // 将文件分成多个chunk
      let size = this.file.size
      let chunks = []
      let start = 0
      let index = 0
      let end = 0
      while (start < size) {
        end = start + this.chunkSize
        if (end > size) {
          end = size
        }
        chunks.push({
          index: index,
          file: this.file.slice(start, end)
        })
        start = end
        index++
      }
      this.chunks = chunks
      this.calculateMD5()
    },
    calculateMD5 () { // 计算文件的MD5值
      let fileReader = new FileReader()
      let self = this
      fileReader.onload = function () {
        let spark = new SparkMD5.ArrayBuffer()
        spark.append(this.result)
        self.md5 = spark.end()
      }
      fileReader.readAsArrayBuffer(this.file)
    },
    upload () { // 上传文件
      let formData = new FormData()
      formData.append('md5', this.md5)
      formData.append('chunks', this.chunks.length)
      this.chunks.forEach((chunk, index) => {
        formData.append('chunk-' + index, chunk.file)
      })
      // 使用axios发送formData到后端
      axios.post('/upload', formData).then(response => {
        console.log(response.data)
      })
    }
  }
}
</script>

2.后端SpringMVC代码：

@RestController
public class FileController {

    @RequestMapping(value = "/upload", method = RequestMethod.POST, consumes = "multipart/form-data")
    public void upload(@RequestParam("md5") String md5, @RequestParam("chunks") Integer chunks,
                       @RequestParam(value = "chunk-0", required = false) MultipartFile file0,
                       @RequestParam(value = "chunk-1", required = false) MultipartFile file1,
                       @RequestParam(value = "chunk-2", required = false) MultipartFile file2,
                       // ...
                       @RequestParam(value = "chunk-" + (chunks - 1), required = false) MultipartFile fileN) {
        // 将分片文件按照索引顺序合并成一个完整的文件
        List<MultipartFile> fileList = new ArrayList<>();
        for (int i = 0; i < chunks; i++) {
            MultipartFile part = request.getFile("chunk-" + i);
            fileList.add(part);
        }
        Collections.sort(fileList, (o1, o2) -> {
            String n1 = o1.getOriginalFilename().split("-")[1];
            String n2 = o2.getOriginalFilename().split("-")[1];
            return Integer.parseInt(n1) - Integer.parseInt(n2);
        });
        byte[] data = null;
        try {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            for (MultipartFile part : fileList) {
                bos.write(part.getBytes());
            }
            data = bos.toByteArray();
            bos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        // 验证文件MD5值是否一致
        String md5OfFile = DigestUtils.md5Hex(data);
        if (md5OfFile.equals(md5)) {
            // 文件上传成功，保存到服务器
            // ...
        } else {
            // 文件上传失败，返回错误信息
            // ...
        }
    }
}

这样就实现了大文件分片上传，并且对上传的文件进行了MD5加密验证。