JavaWeb开发入门问题

我想要发表评论的时候获得时间，并且将时间赋给数据库表的time


<%@ page contentType="text/html;charset=UTF-8" language="java" %>


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Titletitle>
    <style>
        .el-table .warning-row {
            background: oldlace;
        }

        .el-table .success-row {
            background: #f0f9eb;
        }
    style>

head>
<body>

<div id="app">
    <template>
        <div class="demo-type" >
            <div  style="text-align: right">
                <el-avatar src="https://cube.elemecdn.com/0/88/03b0d39583f48206768a7534e55bcpng.png">el-avatar>
            div>
        div>
    template>
    <div  style="text-align: right">${user.username}div>
    
    <el-row>
        <el-button type="info" @click="dialogVisible = true" plain>吐槽el-button>
    el-row>
    
    <el-dialog
            :visible.sync="dialogVisible"
            width="30%"
    >

        <el-form ref="form" :model="comment" label-width="80px">
            <el-form-item label=${user.username}>
            el-form-item>
<%--            <el-form-item>--%>
<%--                <el-input type="hidden" v-model="comment.time">el-input>--%>
<%--            el-form-item>--%>
            <el-form-item label="吐槽">
                <el-input type="textarea" v-model="comment.comment">el-input>
            el-form-item>
            <el-form-item label="话题">
                <el-input v-model="comment.topic">el-input>
            el-form-item>
            
            
            
            
        el-form>

        <span slot="footer" class="dialog-footer">
            <el-button type="primary" @click="onSubmit">吐槽一下el-button>
    <el-button @click="dialogVisible = false">取 消el-button>

  span>
    el-dialog>
    
    <template>
        <el-table
                :data="tableData"
                style="width: 100%"
                :row-class-name="tableRowClassName">

            <el-table-column
                    prop="username"
                    label="用户名"
                    align="center"
                    width="180">
            el-table-column>
            <el-table-column
                    prop="comment"
                    align="center"
                    label="评论">
            el-table-column>
            <el-table-column
                    prop="topic"
                    align="center"
                    label="话题" width="180">
            el-table-column>
            <el-table-column
                    prop="support"
                    align="center"
                    label="支持" width="180">
            el-table-column>
            <el-table-column
                    prop="time"
                    label="日期"
                    align="center"
                    width="180">
            el-table-column>
            <el-table-column
                    label="操作"
                    align="center"
                    width="180">
                <el-row>
                    <el-button type="primary">修改el-button>
                    <el-button type="danger">删除el-button>
                el-row>
            el-table-column>
        el-table>

    template>

div>


<script src="js/vue.js">script>
<script src="element-ui/lib/index.js">script>
<link rel="stylesheet" href="element-ui/lib/theme-chalk/index.css">
<script src="js/axios-0.18.0.js">script>

<script>
    new Vue({
        el: "#app",
        mounted() {
            this.selectAll();
        },

        methods: {
            //查询所有的方法
            selectAll(){
                var _this = this;
                //页面加载后，发送异步请求获取数据
                axios({
                    method: "get",
                    url: "http://localhost:8080/web-demo/selectAllServlet"
                }).then(function (resp) {
                    _this.tableData = resp.data;
                })
            },
            tableRowClassName({row, rowIndex}) {
                if (rowIndex === 1) {
                    return 'warning-row';
                } else if (rowIndex === 3) {
                    return 'success-row';
                }
                return '';
            },
            // addcomment(){
            //   console.log(this.comment)  ;
            // },
            onSubmit() {
                //console.log('submit!');
                // <%--this.username  = ${user.username};--%>
                var _this = this;
                axios({
                    method: "post",
                    url:"http://localhost:8080/web-demo/addServlet",
                    data:_this.comment
                }).then(function (resp){
                    if(resp.data == "success"){
                        //添加成功
                        //关闭窗口
                        _this.dialogVisible = false;
                        //查询所有
                        _this.selectAll();
                    }
                })
            }
        }, data() {
            return {
                //评论数据
                comment:{
                    id:"",
                    username:"${user.username}",
                    comment:'',
                    topic:'',
                    support:'0',
                    time:""
                },
                //添加对话框是否展示
                dialogVisible: false,
                tableData: [{
                }]
            }
        }
    })

script>

body>
html>

数据库字段默认添加时间为当前时间，不用指定这个字段插入

`create_time`     datetime   NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '添加时间',