Implementation

Frontend: Vue Component

A reusable file upload component that converts selected images to base64 format and sends them to the backend.

<template>
  <el-avatar 
    :size="80" 
    :src="avatarSrc" 
    @click="showDialog = true" 
    style="cursor: pointer;"
  >
    <img src="https://cube.elemecdn.com/e/fd/0fc7d20532fdaf769a25683617711.png" />
  </el-avatar>

  <el-drawer v-model="showDialog" title="Upload Image" :with-header="false">
    <el-upload
      class="avatar-uploader"
      :show-file-list="false"
      :on-change="handleFileChange"
      :auto-upload="false"
    >
      <el-icon class="avatar-uploader-icon"><Plus /></el-icon>
    </el-upload>
  </el-drawer>
</template>

<script lang="ts" setup>
import { defineModel, ref } from 'vue';
import { uploadImageApi } from '@/api/modules/upload.ts';

const avatarSrc = defineModel('imageUrl');
const showDialog = ref(false);

const handleFileChange = (file: any) => {
  const fileName = file.name;
  const fileReader = new FileReader();
  
  fileReader.readAsDataURL(file.raw);
  fileReader.onload = (e) => {
    sendToServer(fileName, e.target?.result as string);
  };
};

const sendToServer = (name: string, dataUrl: string) => {
  uploadImageApi.send({ 
    name, 
    base64: dataUrl 
  }).then((response: any) => {
    avatarSrc.value = response;
    showDialog.value = false;
  });
};
</script>

<style scoped>
.avatar-uploader .avatar {
  width: 100px;
  height: 100px;
  display: block;
}
</style>

<style>
.avatar-uploader .el-upload {
  border: 1px dashed var(--el-border-color);
  border-radius: 6px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: var(--el-transition-duration-fast);
}

.avatar-uploader .el-upload:hover {
  border-color: var(--el-color-primary);
}

.el-icon.avatar-uploader-icon {
  font-size: 28px;
  color: #8c939d;
  width: 100px;
  height: 100px;
  text-align: center;
}
</style>

Backend API Service

Spring Boot service that handles base64-encoded file uploads and stores them in the configured directoyr.

package com.example.service;

import cn.hutool.core.codec.Base64;
import cn.hutool.core.io.FileUtil;
import cn.hutool.core.util.IdUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.extra.pinyin.PinyinUtil;
import com.example.dto.FileUploadRequest;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

@Service
public class FileUploadService {

    @Value("${upload.path}")
    private String storagePath;

    @Value("${upload.domain}")
    private String domainUrl;

    public String processUpload(FileUploadRequest request) {
        String originalName = request.getName();
        String dataUrl = request.getBase64();
        
        // Remove data URL prefix and decode base64
        String[] parts = StrUtil.splitToArray(dataUrl, "base64,");
        byte[] imageBytes = Base64.decode(parts[1]);
        
        // Generate unique filename with UUID prefix
        String uniqueName = IdUtil.fastSimpleUUID() + "_" + originalName;
        // Convert Chinese characters to pinyin for better compatibility
        uniqueName = PinyinUtil.getPinyin(uniqueName, "");
        
        // Write file to storage directory
        FileUtil.writeBytes(imageBytes, storagePath + uniqueName);
        
        // Return accessible URL
        return domainUrl + "/images/" + uniqueName;
    }
}

API Endpoint

@PostMapping("/upload")
public String handleUpload(@RequestBody FileUploadRequest request) {
    return fileUploadService.processUpload(request);
}

Configuration

upload:
  path: /var/www/static/images/
  domain: https://your-domain.com

Key Points

FileReader API converts file binary data to a data URL string using the readAsDataURL() method, which produces a base64-encoded string prefixed with data:image/type;base64,.

File Naming Strategy uses UUID prefix to prevent collisions and converts Chinese characters to pinyin for cross-platform compatibility.

nginx Configuration serves the static files from the configured upload path for public access.

Usage Example

<template>
  <div>
    <ImageUploader v-model:imageUrl="userAvatar" />
  </div>
</template>

<script setup>
import ImageUploader from '@/components/ImageUploader.vue';
import { ref } from 'vue';

const userAvatar = ref('');
</script>