vue文件上传, Java后台代码

前端Vue文件内的上传代码示例：

<template>
  <div>
    <input type="file" ref="fileInput" @change="uploadFile" />
  </div>
</template>

<script>
export default {
  methods: {
    async uploadFile() {
      const file = this.$refs.fileInput.files[0]
      const formData = new FormData()
      formData.append('file', file)
      try {
        const response = await this.$http.post('/api/upload', formData)
        console.log(response.data)
      } catch (error) {
        console.log(error)
      }
    }
  }
}
</script>

后端Java代码示例：

import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestPart;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

@RestController
public class UploadController {

    private static final String UPLOADED_FOLDER = "/path/to/upload/folder/";

    @PostMapping("/api/upload")
    public String uploadFile(@RequestPart("file") MultipartFile file) {
        if (file.isEmpty()) {
            return "Please select a file to upload";
        }

        try {
            // Get the file and save it somewhere
            byte[] bytes = file.getBytes();
            Path path = Paths.get(UPLOADED_FOLDER + file.getOriginalFilename());
            Files.write(path, bytes);

            return "You successfully uploaded '" + file.getOriginalFilename() + "'";
        } catch (IOException e) {
            e.printStackTrace();
            return "Failed to upload file";
        }
    }
}

上述示例仅供参考，具体的上传代码需要根据实际需求进行调整。需要注意的是，在使用Java后台处理文件上传时，需要使用MultipartFile类来接收上传的文件。在上传文件之前，需要先设置上传文件的保存路径，并且需要确保该路径是存在的。