element ui实现el-upload用户头像上传（单图上传）

 这是我们要实现的效果

element ui上的代码和效果如下：

<el-upload
  class="avatar-uploader"
  action="https://jsonplaceholder.typicode.com/posts/"
  :show-file-list="false"
  :on-success="handleAvatarSuccess"
  :before-upload="beforeAvatarUpload">
  <img v-if="imageUrl" :src="imageUrl" class="avatar">
  <i v-else class="el-icon-plus avatar-uploader-icon"></i>
</el-upload>

<style>
  .avatar-uploader .el-upload {
    border: 1px dashed #d9d9d9;
    border-radius: 6px;
    cursor: pointer;
    position: relative;
    overflow: hidden;
  }
  .avatar-uploader .el-upload:hover {
    border-color: #409EFF;
  }
  .avatar-uploader-icon {
    font-size: 28px;
    color: #8c939d;
    width: 178px;
    height: 178px;
    line-height: 178px;
    text-align: center;
  }
  .avatar {
    width: 178px;
    height: 178px;
    display: block;
  }
</style>

<script>
  export default {
    data() {
      return {
        imageUrl: ''
      };
    },
    methods: {
      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;
      }
    }
  }
</script>

 接下来我们需要将图片文件上传到接口中，实现代码如下：

<el-form-item label="分类图标" prop="imageUrl" required>
                        <el-upload class="avatar-uploader" :action="action" :headers="headers" :show-file-list="false"
                            :on-success="handleAvatarSuccess" :before-upload="beforeAvatarUpload"
                            style=" border: 1px dashed #d9d9d9;width: 178px;height: 178px;">
                            <img v-if="ruleForm.imageUrl" :src="ruleForm.imageUrl" class="avatar">
                            <i v-else class="el-icon-plus avatar-uploader-icon"></i>
                        </el-upload>
                    </el-form-item>
<script/>
export default {
    components: { Pagination },
    data() {
        return {
    action: `${process.env.VUE_APP_BASE_API}/biz/oss/uploadMinio`,
            headers: {
                Authorization: getToken(),
            },
}
},
methods:{
        handleAvatarSuccess(res, file) {
            this.ruleForm.imageUrl = file.response.data.fullUrl;
        },
        beforeAvatarUpload(file) {
            const isJPG = file.type === 'image/jpeg' || 'image/jpg' || 'image/webp' || 'image/png';
            const isLt2M = file.size / 1024 / 1024 < 2;
            if (!isJPG) {
                this.$message.error('上传头像图片只能是 jgp,jpeg,webp,png格式!');
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!');
            }
            return isJPG && isLt2M;
        },
}
}
<script>