我正在開發(fā)一個項目，前端使用 ReactJS typescript，后端使用 express，數(shù)據(jù)庫使用 MongoDB。我遇到的主要問題是我想以某種方式將數(shù)據(jù)從我的 React 組件發(fā)送到 express 應用程序，以便它可以查詢并將內(nèi)容添加到數(shù)據(jù)庫中。目前，我在 http://localhost:9000 上運行 express 服務器，在 http://localhost:3000 上運行 React 應用程序，我可以使用路由連接它們。我的快遞應用如下所示：var express = require('express');var path = require('path');var cookieParser = require('cookie-parser');var logger = require('morgan');var cors = require('cors');var indexRouter = require('./routes/index');var usersRouter = require('./routes/users');var testAPIRouter = require('./routes/testAPI');var testAddUser = require('./routes/addUser');const MongoClient = require('mongodb').MongoClient;const mongoose = require('mongoose');var app = express();// view engine setupapp.set('views', path.join(__dirname, 'views'));app.set('view engine', 'jade');app.use(cors());app.use(logger('dev'));app.use(express.json());app.use(express.urlencoded({ extended: false }));app.use(cookieParser());app.use(express.static(path.join(__dirname, 'public')));app.use('/', indexRouter);app.use('/users', usersRouter);app.use("/testAPI", testAPIRouter);app.use("/addUser", testAddUser);// catch 404 and forward to error handlerapp.use(function(req, res, next) {  next(createError(404));});// error handlerapp.use(function(err, req, res, next) {  // set locals, only providing error in development  res.locals.message = err.message;  res.locals.error = req.app.get('env') === 'development' ? err : {};  // render the error page  res.status(err.status || 500);  res.render('error');});const dbRoute = 'mongodb+srv://Adminname:fjfeinjd@pawornaw-b4vzg.gcp.mongodb.net/test?retryWrites=true&w=majority';mongoose.connect(dbRoute,    {useNewUrlParser: true})    .then(() => console.log("Connected to MongoDB"))    .catch(err => console.error("Could not connected to Mongo"));module.exports = app;