Elementui实战知识点随记

1. Elementui实战知识点随记

1.1. 表单验证

1. 对于复杂数据，类似于对象里面包含数组，每个数组又包含多个对象，表单验证我查看了网上很多资料都说Elementui不支持，实际上，经过我官网的查看，是有解决办法的，地址如下

https://element.eleme.cn/#/zh-CN/component/form

找到动态增减表单项这一项
核心如下

<el-form :model="dynamicValidateForm" ref="dynamicValidateForm" label-width="100px" class="demo-dynamic">
  <el-form-item
    prop="email"
    label="邮箱"
    :rules="[
      { required: true, message: '请输入邮箱地址', trigger: 'blur' },
      { type: 'email', message: '请输入正确的邮箱地址', trigger: ['blur', 'change'] }
    ]"
  >
    <el-input v-model="dynamicValidateForm.email"></el-input>
  </el-form-item>
  <el-form-item
    v-for="(domain, index) in dynamicValidateForm.domains"
    :label="'域名' + index"
    :key="domain.key"
    :prop="'domains.' + index + '.value'"
    :rules="{
      required: true, message: '域名不能为空', trigger: 'blur'
    }"
  >
    <el-input v-model="domain.value"></el-input><el-button @click.prevent="removeDomain(domain)">删除</el-button>
  </el-form-item>
  <el-form-item>
    <el-button type="primary" @click="submitForm('dynamicValidateForm')">提交</el-button>
    <el-button @click="addDomain">新增域名</el-button>
    <el-button @click="resetForm('dynamicValidateForm')">重置</el-button>
  </el-form-item>
</el-form>

1.2. select动态加载

1. 一定要在data里定义数据，这个亏我吃了两次，定义了个对象在data中，如下，bonus是select中需要添加的数据，userCode是默认值，如果不加默认值这个属性，哪怕在select中定义了，动态加载时也赋值了也是没用的，vue受限于javascript动态赋值的基础必须是data中定义好属性
2. 当组件绑定一个对象的属性，发现组件点击变化没反应，十有八九就是没有定义数据了

form: {
  userCode: '',
  bonus:[]
}

1.3. el-input标签中不能使用@keyup.enter

1. 有时候我们绑定不了事件到Elementui的组件，官网给出了解决办法

https://cn.vuejs.org/v2/guide/components-custom-events.html#%E5%B0%86%E5%8E%9F%E7%94%9F%E4%BA%8B%E4%BB%B6%E7%BB%91%E5%AE%9A%E5%88%B0%E7%BB%84%E4%BB%B6

用 v-on 的 .native 修饰符

1.4. 用axios下载Excel的坑

1.4.1. 获取不到后台文件名

1. 看https://www.cnblogs.com/smiler/p/8708815.html
2. 我的配置，重点是response.setHeader("Access-Control-Expose-Headers", "Content-Disposition");这行

/**
 * filter 接口的自定义实现
 */
@Component
@WebFilter(urlPatterns = "/**", filterName = "corsFilter")
public class CorsFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException,
            ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        response.setHeader("Access-Control-Allow-Origin", "*");
        // or *
        response.setHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS, HEAD");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with,X-Token,x-token, Content-Type, " +
                "MUserAgent, " +
                "MToken, " +
                "UID"); // or *
        response.setHeader("Access-Control-Expose-Headers", "Content-Disposition");
        HttpServletRequest request = (HttpServletRequest) req;
        if(request.getMethod().equals("OPTIONS")) {
            response.setStatus(HttpServletResponse.SC_OK);
        }else{
            chain.doFilter(req, res);
        }
    }

    @Override
    public void destroy() {
    }
}

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