文本，前后端数据交互，简单请求,如何去给data数据赋值，在mounted()里赋值,利用axios发送的请求，res就是数据集，就是后端的数据，this.users = res.data.data

<el-main>
          <div style="display: flex;">
            <el-card style="width: 50%; margin-right: 10px;">
            <template #header>
              <div class="card-header">
                <span>Card name</span>
              </div>
            </template>
            <p v-for="o in 4" :key="o" class="text item">
              {{ "List item " + o }}
            </p>
          </el-card>
          <el-card style="width:50%;">
            <template #header>
              <div class="card-header">
                <span>Card name</span>
              </div>
            </template>
              <div>
                <el-table :data="users">
                  <el-table-column prop="id" label="ID"></el-table-column>
                  <el-table-column prop="username" label="用户名"></el-table-column>
                  <el-table-column prop="name" label="姓名"></el-table-column>
                  <el-table-column prop="address" label="地址"></el-table-column>
                </el-table>  
              </div>
          </el-card>
          </div>
        </el-main>

  mounted(){
    axios.get('http://localhost:9090/user/selectAll').then(res => {
      console.log(res)
    })
  }

export default {
  name: "HomeView",
  data() {
    return {
      isCollapse: false,
      asideWidth: "200px",
      flag: true,
      users: []
    };
  }}

  mounted(){
    axios.get('http://localhost:9090/user/selectAll').then(res => {
      this.users = res.data.data
    })
  }