The simplest file upload display download SpringBoot+vue+MybatisPlus to implement file upload display

renderings

1. yml configuration file

#路径
file:
  path: D:\img\

2', Controller control layer

package com.waimai.ruggie_take_out.controller;

import com.waimai.ruggie_take_out.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.UUID;

@RestController
@RequestMapping("/common")
@Slf4j
public class CommonController {
    
    
	
    @Value("${reggie.path}")
    private String basePath;

    @PostMapping("/upload")
    public R<String> upload(MultipartFile file){
    
    
        log.info(file.toString());

        //原始文件名
        String originalFilename = file.getOriginalFilename();
        String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));

        //使用UUID重新生成文件名，防止文件名重复
        String fileName = UUID.randomUUID().toString() + suffix;

        // 创建一个目录对象
        File dir = new File(basePath);
        //判断当前目录是否存在
        if(!dir.exists()){
    
    
            //目录不存在，需要创建
            dir.mkdirs();
        }

        try{
    
    
            file.transferTo(new File(basePath + fileName));
        }catch (IOException e){
    
    
            e.printStackTrace();
        }
        return R.success(fileName);
    }


    /**
     * 文件下载
     * @param name
     * @param response
     */
    @GetMapping("/download")
    public void download(String name, HttpServletResponse response){
    
    
        try {
    
    
            //输入流，通过输出流，读取文件内容
            FileInputStream fileInputStream = new FileInputStream(new File(basePath + name));

            //输出流，通过输出流将文件写回浏览器，在浏览器展示图片了
            ServletOutputStream outputStream = response.getOutputStream();

            response.setContentType("image/jpeg");

            int len = 0;
            byte[] bytes = new byte[1024];
            while ((len = fileInputStream.read(bytes)) != -1){
    
    
                outputStream.write(bytes,0,len);
                outputStream.flush();
            }

            //关闭资源
            outputStream.close();
            fileInputStream.close();
        }catch (Exception e){
    
    
            e.printStackTrace();
        }

    }
}

3. Front-end Vue

	<div class="container">
        <el-upload class="avatar-uploader"
                action="/common/upload"
                :show-file-list="false"
                :on-success="handleAvatarSuccess"
                :before-upload="beforeUpload"
                ref="upload">
            <img v-if="imageUrl" :src="imageUrl" class="avatar"></img>
            <i v-else class="el-icon-plus avatar-uploader-icon"></i>
        </el-upload>
    </div>
    
     <script>
      new Vue({
    
    
        el: '#food-add-app',
        data() {
    
    
          return {
    
    
            imageUrl: ''
          }
        },
        methods: {
    
    
          handleAvatarSuccess (response, file, fileList) {
    
    
              this.imageUrl = `/common/download?name=${
    
    response.data}`
          },
          beforeUpload (file) {
    
    
            if(file){
    
    
              const suffix = file.name.split('.')[1]
              const size = file.size / 1024 / 1024 < 2
              if(['png','jpeg','jpg'].indexOf(suffix) < 0){
    
    
                this.$message.error('上传图片只支持 png、jpeg、jpg 格式！')
                this.$refs.upload.clearFiles()
                return false
              }
              if(!size){
    
    
                this.$message.error('上传文件大小不能超过 2MB!')
                return false
              }
              return file
            }
          }
        }
      })
    </script>