有时候如果table的header的内容太多而页面的宽度有限，这个时候需要将多长的文字隐藏起来，显示省略号并用弹窗显示全部信息，这时候可以使用render-header这个属性，自定义生成header，看下面的代码：

<template>
  <div class="table-contain">
      <el-table :data="tableData" border style="width: 100%">
        <el-table-column prop="date" label="Date" width="180">
        </el-table-column>
        <el-table-column prop="name" label="Name" width="180">
        </el-table-column>
        <el-table-column
          prop="address"
          label="This is a long long long long long long long long long long Address"
          :render-header="renderHeader"
        >
        </el-table-column>
      </el-table>
  </div>
</template>

<script>
export default {
  name: "elementTable",
  data() {
    return {
      tableData: [
        {
          date: "2016-05-03",
          name: "Tom",
          address: "No. 189, Grove St, Los Angeles",
        },
        {
          date: "2016-05-02",
          name: "Tom",
          address: "No. 189, Grove St, Los Angeles",
        },
        {
          date: "2016-05-04",
          name: "Tom",
          address: "No. 189, Grove St, Los Angeles",
        },
        {
          date: "2016-05-01",
          name: "Tom",
          address: "No. 189, Grove St, Los Angeles",
        },
      ],
    };
  },
  created() {
    let _this = this;
  },
  mounted() {
    let _this = this;
  },
  components: {},
  methods: {
    renderHeader: function (h, { column }) {
      return h(
        "div",
        {
          slot: "content",
          class: "table-header-flex",
        },
        [
          h(
            "el-tooltip",
            {
              props: {
                placement: "top",
              },
            },
            [
              h(
                "div",
                {
                  slot: "content",
                  style: {
                    whiteSpace: "normal",
                  },
                },
                column.label
              ),
              h(
                "span",
                {
                  style: {
                    whiteSpace: "normal",
                    overflow: "hidden",
                    "text-overflow": "ellipsis",
                    "white-space": "nowrap",
                    "max-width": "90%",
                    display: "inline-block",
                  },
                },
                column.label
              ),
            ]
          ),
        ]
      );
    },
  },
};
</script>

<style>
  .table-contain{
    width: 500px;
    height: 100%;
    padding: 10px;
  }
</style>

上面代码中renderHeader方法里要注意column 包含的是每一行的内容，给header添加显示省略号的css代码，并且要把header的文字内容包含在el-tooltip里面
下面的是效果图：