day23
1-使用 koa 搭建服务器
const koa = require('koa') const app = new koa() // 路由请求 // context 上下文 包含req和res app.use(async (ctx)=>{ ctx.body = 'hello koa2' }) app.listen(3000)
2-如何配置 koa 路由
Koa 中的路由和 Express 有所不同，在 Express 中直接引入 Express 就可以配置路由，但是在 Koa 中我们需要安装对应的 koa-router 路由模块来实现
npm install koa-router
const koa = require('koa') const router = require('koa-router')() // 引入和实例化路由 const app = new koa() // 创建koa实列 // 配置路由 //ctx 上下文（content），包含了request和response信息 router.get('/', async (ctx, next) => { ctx.body="Hello koa"; }) router.get('/news', async (ctx, next) => { ctx.body="新闻 page" }); app.use(router.routes()); //作用：启动路由 // 作用： 这是官方文档的推荐用法,我们可以 看到 router.allowedMethods()用在了路由匹配 router.routes()之后 // 所以在当所有 路由中间件最后调用.此时根据 ctx.status 设置 response 响应头 app.use(router.allowedMethods()); // 可以不配置这个，建议配置上 app.listen(3000,()=>{ console.log('starting at port 3000'); })
3-静态资源如何获取
const koa = require('koa') const app = new koa() const router = require('koa-router')() // 加载 const static = require('koa-static') const path = require('path') // 获取静态资源 app.use(static(path.join(__dirname,'public'))) // 启用路由 app.use(router.routes()) .use(router.allowedMethods()) app.listen(3000)
4-koa 如何使用模板引擎
在node中使用模板引擎需要一个中间件koa-views
在koa中使用ejs
安装模块
# 安装koa模板使用中间件 npm install --save koa-views # 安装ejs模板引擎 npm install --save ejs
5-使用 koa 实现一个用户增删改查的案例
搭建前端页面
1.安装antd ,开箱即用的高质量 React 组件。antd design
npm install antd --save
复制代码2.安装axios 一个基于 promise 的 HTTP 库，可以用在浏览器和 node.js 中
npm install axios --save
复制代码因为是一个小demo，因此我直接在 src/App.js 中直接画页面。
src/App.js
import React, { Component } from 'react';
import logo from './logo.svg';
import './App.css';
import axios from 'axios';
import { Table, Pagination, Input, Row, Button, Modal, Form } from 'antd';
import 'antd/dist/antd.css'
const { Search } = Input;
const FormItem = Form.Item;
const { confirm } = Modal;
class App extends Component {
constructor(props) {
super(props);
}
columns = [{
dataIndex: "username", title: "用户",
}, {
dataIndex: "age", title: "年龄",
}, {
dataIndex: "address", title: "地址"
}, {
dataIndex: "action", title: "操作", width: 200, render: (text, row) => {
return <div>
<Button onClick={() => this.modal('edit', row)} >编辑</Button>
<Button style={{ marginLeft: 10 }} type="danger" onClick={() => this.remove(row)} >删除</Button>
</div>
}
}];
state = {
dataSource: [{ username: "slf", age: "18", address: "杭州", id: 1 }],
current: 1,
size: 10,
total: 1,
visible: false,
modalType: "add"
}
componentDidMount() {
this.sizeChange(this.state.current,this.state.size);
}
//分页
sizeChange = (current, size) => {
//todo
}
//提交
handleOk = () => {
//todo
}
//添加编辑用户
modal = (type, row) => {
this.setState({
visible: true,
modalType: type
}, () => {
this.props.form.resetFields();
if (type === 'add') return;
this.props.form.setFieldsValue({
username: row.username,
age: row.age,
address: row.address
})
})
}
remove = (row) => {
confirm({
title: '是否要删除该用户?',
okText: '是',
okType: '否',
cancelText: 'No',
onOk() {
//todo
},
onCancel() {
//todo
},
});
}
render() {
const { getFieldDecorator } = this.props.form;
const formItemLayout = {
labelCol: {
xs: { span: 24 },
sm: { span: 4 },
},
wrapperCol: {
xs: { span: 24 },
sm: { span: 16 },
},
};
return (
<div className="App">
<Row>
<Search style={{ width: 300 }} />
<Button type="primary" style={{ marginLeft: 20 }} onClick={() => this.modal('add')} >添加用户</Button>
</Row>
<Row style={{ paddingTop: 20 }}>
<Table dataSource={this.state.dataSource} rowKey={row => row.id} bordered columns={this.columns} pagination={false} />
</Row>
<Row style={{ paddingTop: 20 }}>
<Pagination
showTotal={(total) => `共 ${total} 条`}
current={this.state.current} total={this.state.total} pageSize={this.state.size}
onChange={this.sizeChange} />
</Row>
<Modal
title={this.state.modalType === 'add' ? "添加用户" : "编辑用户"}
onOk={this.handleOk}
onCancel={() => this.setState({ visible: false })}
visible={this.state.visible}
>
<Form>
<FormItem label="用户" {...formItemLayout}>
{getFieldDecorator('username', {
rules: [{ required: true, message: 'Please input your username!' }],
})(
<Input placeholder="Username" />
)}
</FormItem>
<FormItem label="年龄" {...formItemLayout}>
{getFieldDecorator('age', {
rules: [{ required: true, message: 'Please input your age!' }],
})(
<Input placeholder="age" />
)}
</FormItem>
<FormItem label="地址" {...formItemLayout}>
{getFieldDecorator('address', {
rules: [{ required: true, message: 'Please input your address!' }],
})(
<Input placeholder="address" />
)}
</FormItem>
</Form>
</Modal>
</div >
);
}
}
export default Form.create()(App);
后端搭建
在后端的搭建中我用了koa 和 sequelize
数据库 mysql
koa -- 基于 Node.js 平台的下一代 web 开发框架
Sequelize -- 是JS端的hibernate，完成server端到数据库的CRUD等等操作。
1.安装依赖
npm install koa koa-body koa-cors koa-router sequelize mysql2 --save
复制代码koa-body 因为Web应用离不开处理表单(例如用户的添加编辑表单)。本质上，表单就是 POST 方法发送到服务器的键值对。koa-body模块可以用来从 POST 请求的数据体里面提取键值对。
koa-cors 解决跨域问题
koa-router url处理器映射
2.准备工作
在server目录下面新建以下内容：
/server/app.js 为运行文件 运行方式 node server/app.js
/server/routers 前端访问api路径
/server/model 数据层： index.js 数据库连接 user.js 用户表
3.新建koa服务
/server/app.js
const Koa = require('koa');
const cors = require('koa-cors');
const router = require('./routers/index')
// 创建一个Koa对象表示web app本身:
const app = new Koa();
app.use(cors());//解决跨域问题
// 对于任何请求，app将调用该异步函数处理请求：
app.use(async (ctx, next) => {
console.log(ctx.request.path + ':' + ctx.request.method);
await next();
});
app.use(router.routes());
app.listen(3005);
console.log('app started at port 3005...');
复制代码4.连接数据库
/server/model/index.js
operatorsAliases一定要写true，否则后续使用sql会用问题，例如使用$like模糊查询会出现Invalid value问题
const Sequelize = require('sequelize');
const sequelize = new Sequelize('数据库名', '用户名', '密码', {
host: 'localhost',
dialect: 'mysql',
operatorsAliases: true,
pool: {
max: 5, min: 0, acquire: 30000, idle: 10000
},
define: {
timestamps: false,
},
})
sequelize
.authenticate()
.then(() => {
console.log('Connection has been established successfully.');
})
.catch(err => {
console.error('Unable to connect to the database:', err);
});
module.exports = sequelize;
复制代码5.用户表
根据表设计
/server/model/user.js
sequelize 点击可看使用方式
/server/model/user.js
const Sequelize = require('sequelize')
const sequelize = require('./index')
const User = sequelize.define('userinfos', {
id: { type: Sequelize.INTEGER, autoIncrement: true, primaryKey: true, unique: true },
username: { type: Sequelize.STRING },
age:{type:Sequelize.INTEGER},
address: { type: Sequelize.STRING },
isdelete: { type: Sequelize.INTEGER, allowNull: true }//软删除 0为未删除，1为删除
});
module.exports = User;
复制代码下面重点来了，本文重点，写server！！！！！
因为项目小，我就写在了routers目录内。
/routers/index.js
复制代码1.引入要用的koa-body, koa-router ,数据表（model/user.js）
const koaBody = require('koa-body');
const router = require('koa-router')();
const User = require('../model/user');
复制代码2.第一个api接口：获取所有的用户列表
router.get('/users', async (ctx, next) => {
const user = await User.findAll({
where: { isdelete: 0 },
})
ctx.body = user;
});import React, {Component} from 'react';
import logo from './logo.svg';
import './App.css';
import axios from 'axios';
import {Table, Pagination, Input, Row, Button, Modal, Form, message} from 'antd';
import 'antd/dist/antd.css'
const {Search} = Input;
const FormItem = Form.Item;
const {confirm} = Modal;
class App extends Component {
constructor(props) {
super(props);
}
columns = [{
dataIndex: "username", title: "用户",
}, {
dataIndex: "age", title: "年龄",
}, {
dataIndex: "address", title: "地址"
}, {
dataIndex: "action", title: "操作", width: 200, render: (text, row) => {
return <div>
<Button onClick={() => this.modal('edit', row)}>编辑</Button>
<Button style={{marginLeft: 10}} type="danger" onClick={() => this.remove(row)}>删除</Button>
</div>
}
}];
state = {
dataSource: [],
current: 1,
size: 10,
total: 0,
visible: false,
modalType: "add",
search: "",
editRow: {}
}
componentDidMount() {
this.sizeChange(this.state.current, this.state.size);
}
//分页
sizeChange = (current, size) => {
let data = {
search: this.state.search,
limit: size,
offset: (parseInt(current) - 1) * size
}
axios.post("http://localhost:3005/user-search", data).then(data => {
this.setState({
dataSource: data.data.rows,
total: data.data.count,
current, size
})
})
};
//提交
handleOk = () => {
this.props.form.validateFieldsAndScroll((err, value) => {
if (err) return;
let data = {
username: value.username, age: value.age, address: value.address
};
if (this.state.modalType === 'add') {
axios.post("http://127.0.0.1:3005/user", data)
.then(msg => {
this.sizeChange(this.state.current, this.state.size);
this.setState({visible: false});
message.success('success!')
})
} else {
axios.put("http://127.0.0.1:3005/user/" + this.state.editRow.id, data)
.then(data => {
this.sizeChange(this.state.current, this.state.size);
this.setState({visible: false});
message.success('success!')
})
}
})
}
//添加编辑用户
modal = (type, row) => {
this.setState({
visible: true,
modalType: type
}, () => {
this.props.form.resetFields();
if (type === 'add') return;
this.props.form.setFieldsValue({
username: row.username,
age: row.age,
address: row.address
})
this.setState({editRow: row})
})
}
remove = (row) => {
let _this = this;
confirm({
title: '是否要删除该用户?',
okText: '是',
okType: '否',
cancelText: 'No',
onOk() {
axios.delete("http://127.0.0.1:3005/user/"+row.id)
.then(data=>{
_this.sizeChange(_this.state.current, _this.state.size);
message.success('success!')
})
}
});
};
search = (name) => {
this.setState({
search: name
}, () => {
this.sizeChange(1, 10)
})
};
render() {
const {getFieldDecorator} = this.props.form;
const formItemLayout = {
labelCol: {
xs: {span: 24},
sm: {span: 4},
},
wrapperCol: {
xs: {span: 24},
sm: {span: 16},
},
};
return (
<div className="App">
<Row>
<Search style={{width: 300}} onChange={this.search}/>
<Button type="primary" style={{marginLeft: 20}} onClick={() => this.modal('add')}>添加用户</Button>
</Row>
<Row style={{paddingTop: 20}}>
<Table dataSource={this.state.dataSource} rowKey={row => row.id} bordered columns={this.columns}
pagination={false}/>
</Row>
<Row style={{paddingTop: 20}}>
<Pagination
showTotal={(total) => `共 ${total} 条`}
current={this.state.current} total={this.state.total} pageSize={this.state.size}
onChange={this.sizeChange}/>
</Row>
<Modal
title={this.state.modalType === 'add' ? "添加用户" : "编辑用户"}
onOk={this.handleOk}
onCancel={() => this.setState({visible: false})}
visible={this.state.visible}
>
<Form>
<FormItem label="用户" {...formItemLayout}>
{getFieldDecorator('username', {
rules: [{required: true, message: 'Please input your username!'}],
})(
<Input placeholder="username"/>
)}
</FormItem>
<FormItem label="年龄" {...formItemLayout}>
{getFieldDecorator('age', {
rules: [{required: true, message: 'Please input your age!'}],
})(
<Input placeholder="age"/>
)}
</FormItem>
<FormItem label="地址" {...formItemLayout}>
{getFieldDecorator('address', {
rules: [{required: true, message: 'Please input your address!'}],
})(
<Input placeholder="address"/>
)}
</FormItem>
</Form>
</Modal>
</div>
);
}
}
export default Form.create()(App);
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