Nodeexpress写接口的详细步骤

通过模块express来写接口

express介绍

案例

解决跨域问题

• 安装cors模块
• 代码中&＃xff0c;在所有接口之前&＃xff0c;加载cors

使用express 搭建web服务器


// 1) 加载 express 模块
const express &＃61; require(&＃39;express&＃39;);// 2) 创建 express 服务器
const app &＃61; express();// 3) 监听浏览器请求并进行处理app.get(&＃39;GET请求的地址&＃39;, 处理函数);app.post(&＃39;POST请求的地址&＃39;, 处理函数);// 4) 开启服务器
app.listen(3000, () &＃61;> console.log(&＃39;express服务器开始工作了&＃39;));

写接口

1.下载安装所需模块 express
2.准备好相应的json文件
3.创建index.js

// 用于启动服务&＃xff0c;并且写接口
const express &＃61; require(&＃39;express&＃39;)
const app &＃61; express()// 写接口
// app.请求方式(&＃39;接口地址&＃39;, &＃39;带有req、res参数的处理函数&＃39;);
// app.get(&＃39;/api/student&＃39;, (req, res) &＃61;> {});
// app.post();
// app.delete();
// app.put();app.listen(3000, () &＃61;> console.log(&＃39;启动了&＃39;));

使用 nodemon index.js 启动服务

接口案例&＃xff1a;

写一个获取市的接口
1.npm i express
2.准备文件&＃xff1a;city.json

{"内蒙古自治区": {"呼和浩特市": ["新城区","回民区","玉泉区","赛罕区","土默特左旗","托克托县","和林格尔县","清水河县","武川县"],"包头市": ["东河区","昆都仑区","青山区","石拐区","白云鄂博矿区","九原区","土默特右旗","固阳县","达尔罕茂明安联合旗"],"乌海市": ["海勃湾区","海南区","乌达区"],"赤峰市": ["红山区","元宝山区","松山区","阿鲁科尔沁旗","巴林左旗","巴林右旗","林西县","克什克腾旗","翁牛特旗","喀喇沁旗","宁城县","敖汉旗"],"通辽市": ["科尔沁区","科尔沁左翼中旗","科尔沁左翼后旗","开鲁县","库伦旗","奈曼旗","扎鲁特旗","霍林郭勒市"],"鄂尔多斯市": ["东胜区","康巴什区","达拉特旗","准格尔旗","鄂托克前旗","鄂托克旗","杭锦旗","乌审旗","伊金霍洛旗"],"呼伦贝尔市": ["海拉尔区","扎赉诺尔区","阿荣旗","莫力达瓦达斡尔族自治旗","鄂伦春自治旗","鄂温克族自治旗","陈巴尔虎旗","新巴尔虎左旗","新巴尔虎右旗","满洲里市","牙克石市","扎兰屯市","额尔古纳市","根河市"],"巴彦淖尔市": ["临河区","五原县","磴口县","乌拉特前旗","乌拉特中旗","乌拉特后旗","杭锦后旗"],"乌兰察布市": ["集宁区","卓资县","化德县","商都县","兴和县","凉城县","察哈尔右翼前旗","察哈尔右翼中旗","察哈尔右翼后旗","四子王旗","丰镇市"],"兴安盟": ["乌兰浩特市","阿尔山市","科尔沁右翼前旗","科尔沁右翼中旗","扎赉特旗","突泉县"],"锡林郭勒盟": ["二连浩特市","锡林浩特市","阿巴嘎旗","苏尼特左旗","苏尼特右旗","东乌珠穆沁旗","西乌珠穆沁旗","太仆寺旗","镶黄旗","正镶白旗","正蓝旗","多伦县"],"阿拉善盟": ["阿拉善左旗","阿拉善右旗","额济纳旗"]}},


3.创建index.js

const express &＃61; require(&＃39;express&＃39;)
const app &＃61; express()// 写接口
let cities &＃61; require(&＃39;./city.json&＃39;); // 加载所有的省市县app.get(&＃39;/api/province&＃39;, (req, res) &＃61;> {// 处理数据&＃xff0c;将所有的省取得app.get(&＃39;/api/city&＃39;, (req, res) &＃61;> {let pname &＃61; req.query.pname; // 这行代码的意思是获取 url后拼接的 查询参数if (pname) { // 判断&＃xff0c;如果能够取得pname参数let city &＃61; [];for (key in cities[pname]) {city.push(key);}res.send(city);} else {res.send({code: 1, message: &＃39;pname参数必填&＃39;})}
});
})app.listen(3000, () &＃61;> console.log(&＃39;启动了&＃39;))


4.结果