template a-card bordered=false !-- 查询区域 -- div class=table-page-search-wrapper a-form layout=inline keyupenternative=searchQuery a-row gutter=24 a-row a-form div !

在data中的columns数组中，找到单位列的对象，并给它添加一个scopedSlots属性，将其值设置为一个对象，对象的属性名为customRender，属性值为一个函数。在这个函数中，我们可以对表格中的每一行数据进行自定义渲染。

具体代码如下：

data() {
  return {
    description: 'vmi替换记录管理页面',
    // 表头
    columns: [
      {
        title: '#',
        dataIndex: '',
        key: 'rowIndex',
        width: 60,
        align: "center",
        customRender: function (t, r, index) {
          return parseInt(index) + 1;
        }
      },
      {
        title: '单位',
        align: "center",
        dataIndex: 'unit',
        scopedSlots: {  // 添加scopedSlots属性
          customRender: 'unitRender'  // 设置自定义渲染函数的名称
        }
      },
      {
        title: '操作',
        dataIndex: 'action',
        align: "center",
        width: 147,
        scopedSlots: { customRender: 'action' }
      }
    ],
    url: {
      list: "/vmiReplaceRecordService/vmiReplaceRecord/list",
      delete: "/vmiReplaceRecordService/vmiReplaceRecord/delete",
      deleteBatch: "/vmiReplaceRecordService/vmiReplaceRecord/deleteBatch",
      exportXlsUrl: "/vmiReplaceRecordService/vmiReplaceRecord/exportXls",
      importExcelUrl: "vmiReplaceRecordService/vmiReplaceRecord/importExcel",
    },
    dictOptions: {},
  }
},

然后，在<template>中添加一个template标签，设置slot属性的值为unitRender，在这个template标签中，可以自定义渲染单位列的内容。我们可以使用a-input组件来实现一个带有默认值的输入框，并将unit的值绑定到输入框的value属性上。具体代码如下：

<template slot="unitRender" slot-scope="text, record">
  <a-input :value="record.unit || 'KG'" disabled></a-input>
</template>

这样，当单位列没有值时，会显示默认的单位KG。

完整代码如下：

<template>
  <a-card :bordered="false">
    <!-- 查询区域 -->
    <div class="table-page-search-wrapper">
      <a-form layout="inline" @keyup.enter.native="searchQuery">
        <a-row :gutter="24">
        </a-row>
      </a-form>
    </div>
    <!-- 查询区域-END -->
    
    <!-- 操作按钮区域 -->
    <div class="table-operator">
      <a-button @click="handleAdd" type="primary" icon="plus">新增</a-button>
      <a-button type="primary" icon="download" @click="handleExportXls('vmi替换记录')">导出</a-button>
      <a-upload name="file" :showUploadList="false" :multiple="false" :headers="tokenHeader" :action="importExcelUrl" @change="handleImportExcel">
        <a-button type="primary" icon="import">导入</a-button>
      </a-upload>
      <a-dropdown v-if="selectedRowKeys.length > 0">
        <a-menu slot="overlay">
          <a-menu-item key="1" @click="batchDel"><a-icon type="delete"/>删除</a-menu-item>
        </a-menu>
        <a-button style="margin-left: 8px"> 批量操作 <a-icon type="down" /></a-button>
      </a-dropdown>
    </div>

    <!-- table区域-begin -->
    <div>
      <div class="ant-alert ant-alert-info" style="margin-bottom: 16px;">
        <i class="anticon anticon-info-circle ant-alert-icon"></i> 已选择 <a style="font-weight: 600">{{ selectedRowKeys.length }}</a>项
        <a style="margin-left: 24px" @click="onClearSelected">清空</a>
      </div>

      <a-table
        ref="table"
        size="middle"
        bordered
        rowKey="id"
        :columns="columns"
        :dataSource="dataSource"
        :pagination="ipagination"
        :loading="loading"
        :rowSelection="{selectedRowKeys: selectedRowKeys, onChange: onSelectChange}"
        class="j-table-force-nowrap"
        @change="handleTableChange">

        <template slot="htmlSlot" slot-scope="text">
          <div v-html="text"></div>
        </template>
        <template slot="imgSlot" slot-scope="text">
          <span v-if="!text" style="font-size: 12px;font-style: italic;">无图片</span>
          <img v-else :src="getImgView(text)" height="25px" alt="" style="max-width:80px;font-size: 12px;font-style: italic;"/>
        </template>
        <template slot="fileSlot" slot-scope="text">
          <span v-if="!text" style="font-size: 12px;font-style: italic;">无文件</span>
          <a-button
            v-else
            :ghost="true"
            type="primary"
            icon="download"
            size="small"
            @click="uploadFile(text)">
            下载
          </a-button>
        </template>

        <span slot="action" slot-scope="text, record">
          <a @click="handleEdit(record)">编辑</a>

          <a-divider type="vertical" />
          <a-dropdown>
            <a class="ant-dropdown-link">更多 <a-icon type="down" /></a>
            <a-menu slot="overlay">
              <a-menu-item>
                <a-popconfirm title="确定删除吗?" @confirm="() => handleDelete(record.id)">
                  <a>删除</a>
                </a-popconfirm>
              </a-menu-item>
            </a-menu>
          </a-dropdown>
        </span>

      </a-table>
    </div>

    <vmiReplaceRecord-modal ref="modalForm" @ok="modalFormOk"></vmiReplaceRecord-modal>
  </a-card>
</template>

<script>

  import '@/assets/less/TableExpand.less'
  import { mixinDevice } from '@/utils/mixin'
  import { JeecgListMixin } from '@/mixins/JeecgListMixin'
  import VmiReplaceRecordModal from './modules/VmiReplaceRecordModal'

  export default {
    name: "VmiReplaceRecordList",
    mixins:[JeecgListMixin, mixinDevice],
    components: {
      VmiReplaceRecordModal
    },
    data () {
      return {
        description: 'vmi替换记录管理页面',
        // 表头
        columns: [
          {
            title: '#',
            dataIndex: '',
            key:'rowIndex',
            width:60,
            align:"center",
            customRender:function (t,r,index) {
              return parseInt(index)+1;
            }
          },
          {
            title:'单位',
            align:"center",
            dataIndex: 'unit',
            scopedSlots: {  // 添加scopedSlots属性
              customRender: 'unitRender'  // 设置自定义渲染函数的名称
            }
          },
          {
            title: '操作',
            dataIndex: 'action',
            align:"center",
            // fixed:"right",
            width:147,
            scopedSlots: { customRender: 'action' }
          }
        ],
        url: {
          list: "/vmiReplaceRecordService/vmiReplaceRecord/list",
          delete: "/vmiReplaceRecordService/vmiReplaceRecord/delete",
          deleteBatch: "/vmiReplaceRecordService/vmiReplaceRecord/deleteBatch",
          exportXlsUrl: "/vmiReplaceRecordService/vmiReplaceRecord/exportXls",
          importExcelUrl: "vmiReplaceRecordService/vmiReplaceRecord/importExcel",
        },
        dictOptions:{},
      }
    },
    computed: {
      importExcelUrl: function(){
        return `${window._CONFIG['domianURL']}/${this.url.importExcelUrl}`;
      },
    },
    methods: {
      initDictConfig(){
      }
    }
  }
</script>
<style scoped>
  @import '~@assets/less/common.less';
</style>
<template slot="unitRender" slot-scope="text, record">
  <a-input :value="record.unit || 'KG'" disabled></a-input>
</template>

这样，单位默认为KG的功能就实现了。