Failed to load http://localhost:8090/category/lists: The value of the 'Access-Control-Allow-Origin' header in the response must not be the wildcard '*' when the request's credentials mode is 'include'. Origin 'http://localhost:8081' is therefore not allowed access. The credentials mode of requests initiated by the XMLHttpRequest is controlled by the withCredentials attribute.

const express = require('express')
const app = express()
const cors = require('cors') // 此處我的項(xiàng)目中使用express框架，跨域使用了cors npm插件
app.use(cors{
   credentials: true, 
   origin: 'http://localhost:8081', // web前端服務(wù)器地址
   // origin: '*' // 這樣會(huì)出錯(cuò)
  })

import axios from 'axios'
// 創(chuàng)建axios實(shí)例
const service = axios.create({
 baseURL: process.env.BASE_API, // node環(huán)境的不同，對(duì)應(yīng)不同的baseURL
 timeout: 5000, // 請(qǐng)求的超時(shí)時(shí)間
 //設(shè)置默認(rèn)請(qǐng)求頭，使post請(qǐng)求發(fā)送的是formdata格式數(shù)據(jù)// axios的header默認(rèn)的Content-Type好像是'application/json;charset=UTF-8',我的項(xiàng)目都是用json格式傳輸，如果需要更改的話(huà)，可以用這種方式修改
 // headers: { 
 // "Content-Type": "application/x-www-form-urlencoded"
 // },
 withCredentials: true // 允許攜帶cookie
})
// 發(fā)送請(qǐng)求前處理request的數(shù)據(jù)
axios.defaults.transformRequest = [function (data) {
 let newData = ''
 for (let k in data) {
 newData += encodeURIComponent(k) + '=' + encodeURIComponent(data[k]) + '&'
 }
 return newData
}]
// request攔截器
service.interceptors.request.use(
 config => {
 // 發(fā)送請(qǐng)求之前，要做的業(yè)務(wù)
 return config
 },
 error => {
 // 錯(cuò)誤處理代碼
 
 return Promise.reject(error)
 }
)
// response攔截器
service.interceptors.response.use(
 response => {
 // 數(shù)據(jù)響應(yīng)之后，要做的業(yè)務(wù)
 return response
 },
 error => {
 return Promise.reject(error)
 }
)
export default service

import fetch from '@/utils/fetch'
fetch({
 method: 'get',
 url: '/users/list'
})
 .then(res => {
 cosole.log(res)
})