问题描述
我正在上NodeJS课程，其中有一些与路由相关的作业，除了这部分似乎还有些奇怪之外，其他一切工作都很好：由于某种原因，我无法读取传递给已安装路由器的参数ID。
dish.js
const express = require('express');
const bodyParser = require('body-parser');
const dishRouter = express.Router();
dishRouter.use(bodyParser.json());
dishRouter.route('/')
.all((req,res,next) => {
res.statusCode = 200;
res.setHeader('Content-Type','text/plain');
next();
})
.get((req,res) => {
console.info('Info: ',req);
res.end(`Sending details of the dish back to you: ${req.params.dishId}`);
})
.post((req,res) => {
res.statusCode = 403;
res.end(`Operation not supported: ${req.params.dishId}`);
})
.put((req,res) => {
res.write(`Updating the dish...: ${req.params.dishId} \n` );
res.end(`Will update this dish: ${req.body.name} with details: ${req.body.description}`);
})
.delete((req,res) => {
res.end(`Deleting this dish: ${req.params.dishId}`);
});
exports.dish = dishRouter;
dishes.js
const express = require('express');
const bodyParser = require('body-parser');
const dishesRouter = express.Router();
dishesRouter.use(bodyParser.json());
dishesRouter.route('/')
.all((req,'text/plain');
next();
})
.get((req,res) => {
res.end('Sending all dishes back to you');
})
.post((req,res) => {
res.end(`Will add the dish: ${req.body.name} with details: ${req.body.description}`);
})
.put((req,res) => {
res.statusCode = 403;
res.end(`Operation not supported.`);
})
.delete((req,res) => {
res.end(`Deleting all dishes.....`);
});
exports.dishes = dishesRouter;
index.js
const express = require('express');
const morgan = require('morgan');
const bodyParser = require('body-parser');
const http = require('http');
const dishRouter = require('./routes/dish');
const dishesRouter = require('./routes/dishes');
const hostname = 'localhost';
const port = 3000;
const app = express();
app.use(morgan('dev'));
app.use(bodyParser.json());
app.use('/dishes',dishesRouter.dishes);
app.use('/dishes/:dishId',dishRouter.dish);
app.use(express.static(__dirname+'/public'));
app.use((req,'text/html');
res.end('<html><body><h1>This is an Express Server</h1></body></html>');
});
const server = http.createServer(app);
server.listen(port,hostname,(req,res) => {
console.info(`Server running on port: ${port},at: ${hostname}`);
})
此GET localhost：3000 / dishes / 123 调用了正确的路由，但是参数盘ID返回为“未定义”。再次，仅学习nodeJS，似乎我的接收器/安装的路由应该接收那些参数就好了，可以正确读取主体，但不能读取参数。 ...谢谢。
解决方法
是的，参数不会在路由器之间流动。您在新路由器上，因此是新的路由参数对象。
您可以查看以下代码： https://github.com/expressjs/express/blob/master/lib/router/index.js#L43 检出第43行和第53行，其中route.params设置为空对象。
一些例子：
index.js
app.use('/dishes/:dishId',(req,res) => {
console.log('now I get my dishId',req.params.dishId)
});
dish.js（版本1）
dishRouter.route('/')
.get((req,res) => {
console.log('now i get nothing',req.params)
})
dish.js（版本2）
dishRouter.route('/:anotherId')
.get((req,res) => {
console.log('now we get another parameter',req.params.anotherId)
})
// the path would be /dish/123/456
我不确定是否存在offical-expressjs-way在路由器之间传递params对象。
一种解决方案是创建自定义处理程序
index.js
app.use('/dishes/:dishId',handler)
handler.js
function handler (req,res,next) {
if (req.method === 'GET') {
console.log('now we get it',req.params)
}
}
module.exports = handler
另一种方法是在调用路由器之前将dishId添加到请求对象：
index.js
app.use('/dishes/:dishId',next) => {
req.dishId = req.params.dishId
router(req,next)
})
dish.js
const express = require('express')
const router = express.Router()
router.route('/')
.get((req,res) => {
console.log('nothing here',req.params)
console.log('dishId',req.dishId)
})
module.exports = router
第三种方式是将参数作为选项发送到路由器功能
index.js
app.use('/dishes/:dishId',next) => {
router(req.params)(req,next)
})
dish.js
function createRouter (options) {
const router = express.Router()
router.route('/')
.get((req,req.params)
console.log('but alot here',options)
})
return router
}
module.exports = createRouter
如果需要，您也可以将：dishId作为可选参数放置在路由器上
index.js
app.use('/dishes',dishesRouter)
dishes.js
const express = require('express')
const router = express.Router()
router.route('/:dishId?')
.get((req,res) => {
if (req.params.dishId) {
res.end(`Sending details of the dish back to you: ${req.params.dishId}`)
} else {
res.end('Sending all dishes back to you');
}
})
module.exports = router
依赖报错 idea导入项目后依赖报错，解决方案：https://blog....
错误1：gradle项目控制台输出为乱码 # 解决方案：https://bl...