利用Springboot+vue实现图片上传至数据库并显示的全过程

<el-upload
     ref="upload"
     class="avatar-uploader"
     action="/setimg"
     :http-request="picUpload"
     :show-file-list="false"
     :auto-upload="false"
     :on-success="handleAvatarSuccess"
     :before-upload="beforeAvatarUpload">
   <img v-if="$hostURL+imageUrl" :src="$hostURL+imageUrl" class="avatar">
   <i v-else class="el-icon-plus avatar-uploader-icon"></i>
 </el-upload>

<el-button type="primary" @click="submitUpload">修改</el-button>

//在main.js中
	Vue.prototype.$hostURL='http://localhost:8082'

methods:{
//这里是官方的方法不变
	handleAvatarSuccess(res, file){
	      this.imageUrl = URL.createObjectURL(file.raw);
	},
    beforeAvatarUpload(file) {
      const isJPG = file.type === 'image/jpeg';
      const isLt2M = file.size / 1024 / 1024 < 2;

      if (!isJPG) {
        this.$message.error('上传头像图片只能是 JPG 格式!');
      }
      if (!isLt2M) {
        this.$message.error('上传头像图片大小不能超过 2MB!');
      }
      return isJPG && isLt2M;
    },
//这里是自定义发送请求
    picUpload(f){
     let params = new FormData()
     //注意在这里一个坑f.file
     params.append("file",f.file);
     this.$axios({
       method:'post',
       //这里的id是我要改变用户的ID值
       url:'/setimg/'+this.userForm.id,
       data:params,
       headers:{
         'content-type':'multipart/form-data'
       }
     }).then(res=>{
     //这里是接受修改完用户头像后的JSON数据
       this.$store.state.menu.currentUserInfo=res.data.data.backUser
       //这里返回的是头像的url
       this.imageUrl = res.data.data.backUser.avatar
     })
   },
   //触发请求
    submitUpload(){
   this.$refs.upload.submit();
 	}
}

@Data
public class SysUser extends BaseEntity{
//这里的BaseEntity是id,statu,created,updated数据
    private static final Long serialVersionUID = 1L;

    @NotBlank(message = "用户名不能为空")
    private String username;

//    @TableField(exist = false)
    private String password;
    @NotBlank(message = "用户名称不能为空")
    private String name;
    //头像
    private String avatar;

    @NotBlank(message = "邮箱不能为空")
    @Email(message = "邮箱格式不正确")
    private String email;
    private String tel;
    private String address;
    @TableField("plevel")
    private Integer plevel;
    private LocalDateTime lastLogin;
}

@Mapper
@TableName("sys_user")
public interface SysUserMapper extends BaseMapper<SysUser> {
}

    @Value("${file.upload-path}")
    private String pictureurl;
    @PostMapping("/setimg/{id}")
    public Result setImg(@PathVariable("id") Long id, @RequestBody MultipartFile file){
        String fileName = file.getOriginalFilename();
        File saveFile = new File(pictureurl);
        //拼接url，采用随机数，保证每个图片的url不同
        UUID uuid = UUID.randomUUID();
        //重新拼接文件名，避免文件名重名
        int index = fileName.indexOf(".");
        String newFileName ="/avatar/"+fileName.replace(".","")+uuid+fileName.substring(index);
        //存入数据库，这里可以加if判断
        SysUser user = new SysUser();
        user.setId(id);
        user.setAvatar(newFileName);
        sysUserMapper.updateById(user);
        try {
            //将文件保存指定目录
            file.transferTo(new File(pictureurl + newFileName));
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("保存成功");
        SysUser ret_user = sysUserMapper.selectById(user.getId());
        ret_user.setPassword("");
        return Result.succ(MapUtil.builder()
                .put("backUser",ret_user)
                .map());
    }

file:
  upload-path: D:\Study\MyAdmin\scr

@Configuration
public class WebConfig implements WebMvcConfigurer{
    private String filePath = "D:/Study/MyAdmin/scr/avatar/";
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/avatar/**").addResourceLocations("file:"+filePath);
        System.out.println("静态资源获取");
    }
}

module.exports = {
    devServer: {
        // 端口号
        open: true,
        host: 'localhost',
        port: 8080,
        https: false,
        hotOnly: false,
        // 配置不同的后台API地址
        proxy: {
            '/api': {
            //后端端口号
                target: 'http://localhost:8082',
                ws: true,
                changOrigin: true,
                pathRewrite: {
                    '^/api': ''
                }
            }
        },
        before: app => {}
    }
}

	axios.defaults.baseURL = '/api'