Vue 2.0 中的 Vuex Store 状态管理器核心概念和组成部分

State（状态）：
Vuex Store 的核心就是集中式存储应用的所有组件的状态。它是一个单一状态树，所有的组件都从这个状态树中读取数据并可以响应状态的变化。

const state = {
  count: 0,
  user: null,
  // 更多的状态...
}

Getters（获取器）：
类似于 Vue 组件中的计算属性，Getters 接受 State 作为输入，并返回处理过的状态数据。它们允许你定义从 State 派生出的新状态，且当 State 改变时自动更新。

const getters = {
  formattedCount: state => `Count is ${state.count}`,
  loggedInUser: state => state.user && state.user.loggedIn ? state.user : null,
  // 更多的获取器...
}

Mutations（突变)
修改 Vuex Store 中的状态的唯一方式是通过提交 mutation。每个 mutation 都是一个纯函数，接受 State 作为第一个参数，并接收 payload 作为额外参数来修改 State。

const mutations = {
  increment(state) {
    state.count++;
  },
  setUser(state, user) {
    state.user = user;
  },
  // 更多的突变...
}

Actions（动作）
Actions 是用于触发 mutations 并包含异步操作的地方。它们通常用来执行异步逻辑（如 AJAX 请求），并在完成后提交 mutation 来改变 State。某些情况下，可能需要通过异步操作来设置某个store状态，这时可以创建一个action来处理整个过程，并在成功后调用mutation更新状态。

const actions = {
  async incrementAsync({ commit }) {
    setTimeout(() => {
      commit('increment');
    }, 1000);
  },
  fetchUser({ commit }) {
    return axios.get('/api/user')
      .then(response => {
        commit('setUser', response.data);
      });
  },
  // 更多的动作...
}

Modules（模块）
在大型应用中，Store 可以被细分为多个模块，每个模块拥有自己的 State、Getters、Mutations 和 Actions。这样有助于组织代码，使得状态管理更加清晰和可维护。

// example module
const userModule = {
  state: { ... },
  getters: { ... },
  mutations: { ... },
  actions: { ... },
}

export default new Vuex.Store({
  modules: {
    user: userModule,
    // 其他模块...
  }
})

完整应用示例
文件结构：
store/modules/…：被细分的模块
store/index.js：总和被细分的模块
store/getters.js：接受 State 作为输入，并返回处理过的状态数据， State 改变时自动更新。
main.js:引入store并应用到vue

以细分模块user.js为例：
（1）user.js

import { login, logout } from '@/api/login'  /* 自己封装的登录退出请求*/
import { getToken, setToken, removeToken } from '@/utils/auth' /*cookie管理token文件*/
const user = {
  state: {
    token: getToken(),
    userName: localStorage.getItem("userName")||'',//用户名
    permissions: [],
    isRouter:true,
    isLargeScreen:JSON.parse(localStorage.getItem("isLargeScreen")||"true"),//全屏显示驾驶舱
  },
  mutations: {
    SET_TOKEN: (state, token) => {
      state.token = token
    },
    USER_NAME: (state, userName) => {
      state.userName = userName
    },
    SET_PERMISSIONS: (state, permissions) => {
      state.permissions = permissions
    },
    IS_ROUTER: (state, isRouter) => {
      state.isRouter = isRouter
    },
    IS_LargeScreen(state, isLargeScreen){
      state.isLargeScreen = isLargeScreen
    },
    changeStateMutations1(state, data) {
    	//data:{key:需要修改的名，data：修改的内容}
    	state[data.key] = data.data;
    	if (typeof(state[data.key]) != "undefined") {
    		return true;
    	} else {
    		return false;
    	}
    },
    system_ID:(state, systemId)=>{
      state.systemId = systemId
    },
    IS_System:(state, isSystem)=>{
      state.isSystem = isSystem
    }
  },

  actions: {
    setSuperAdminType({ commit, state }, view) {
      return new Promise(resolve => {
        resolve([...state.superAdminType])
      })
    },
    // 登录
    Login({ commit }, userInfo) {
      const username = userInfo.username.trim()
      const password = userInfo.password

      return new Promise((resolve, reject) => {
        login(username, password).then(res => {
         //console.log(res.isAiAdmin,"登录返回值");
          setToken(res.content.token)
          commit('SET_TOKEN', res.content.token)
          //用户名
          localStorage.setItem("userName",res.content.userName)
          commit('USER_NAME', res.content.userName)
          resolve()
        }).catch(error => {
          reject(error)
        })
      })
    },

    // 退出系统
    LogOut({ commit, state }) {
      return new Promise((resolve, reject) => {
        logout({token:state.token}).then(() => {
          commit('SET_TOKEN', '')
          commit('USER_NAME', [])
          removeToken()
          resolve()
        }).catch(error => {
          reject(error)
        })
      })
    },

    // 前端 登出
    FedLogOut({ commit }) {
      return new Promise(resolve => {
        commit('SET_TOKEN', '')
        removeToken()
        resolve()
      })
    },
    //修改数据
    changeStateData(context, data) {
    //data:{key:需要修改的名，data：修改的内容}
      context.commit('changeStateMutations1', data)
    },
  }
}

export default user

（2）@/utils/auth（机制跟localstorage类似可以不用该文件）

import Cookies from 'js-cookie'

const TokenKey = 'Admin-cms-Token'

export function getToken() {
  return Cookies.get(TokenKey)
}

export function setToken(token) {
  return Cookies.set(TokenKey, token)
}

export function removeToken() {
  return Cookies.remove(TokenKey)
}

（3）getters.js

const getters = {
  sidebar: state => state.app.sidebar,
  size: state => state.app.size,
  device: state => state.app.device,
  visitedViews: state => state.tagsView.visitedViews,
  cachedViews: state => state.tagsView.cachedViews,
  token: state => state.user.token,
  avatar: state => state.user.avatar,
  userName: state => state.user.userName,
  introduction: state => state.user.introduction,
  permissions: state => state.user.permissions,
  permission_routes: state => state.permission.routes,
  topbarRouters:state => state.permission.topbarRouters,
  defaultRoutes:state => state.permission.defaultRoutes,
  sidebarRouters:state => state.permission.sidebarRouters,
  isRouter: state => state.user.isRouter,
  isLargeScreen:state => state.user.isLargeScreen,

}
export default getters

(4)index.js

import Vue from 'vue'
import Vuex from 'vuex'
import app from './modules/app'
import user from './modules/user'
import tagsView from './modules/tagsView'
import permission from './modules/permission'
import settings from './modules/settings'
import getters from './getters'

Vue.use(Vuex)

const store = new Vuex.Store({
  modules: {
    app,
    user,
    tagsView,
    permission,
    settings
  },
  getters
})
export default store

(5)main.js中引入store并运用到vue上

import Vue from 'vue'

import Cookies from 'js-cookie'

import Element from 'element-ui'
import './assets/styles/element-variables.scss'

import '@/assets/styles/index.scss' // global css
import '@/assets/styles/ruoyi.scss' // ruoyi css
import './assets/icons'
import Common from "@/utils/common.js";


import App from './App'
import store from './store'
import router from './router'
import directive from './directive' // directive
import plugins from './plugins' // plugins


import './permission' // permission control
import { parseTime, resetForm, addDateRange, selectDictLabel, selectDictLabels, handleTree } from "@/utils/ruoyi";
// 分页组件
import Pagination from "@/components/Pagination";
//右上角菜单
import TopMenu from "@/components/topMenu";
// 自定义表格工具组件
import RightToolbar from "@/components/RightToolbar"
// 分页组件
import newInput from "@/components/newInput";

// 头部标签组件
import VueMeta from 'vue-meta'

// 全局方法挂载
Vue.prototype.parseTime = parseTime
Vue.prototype.resetForm = resetForm
Vue.prototype.addDateRange = addDateRange
Vue.prototype.selectDictLabel = selectDictLabel
Vue.prototype.selectDictLabels = selectDictLabels
Vue.prototype.handleTree = handleTree

// 全局组件挂载
Vue.component('Pagination', Pagination)
Vue.component('RightToolbar', RightToolbar)
Vue.component('newInput', newInput)
Vue.component('TopMenu', TopMenu)

Vue.use(directive)
Vue.use(plugins)
Vue.use(VueMeta)
Vue.use(Common)

Vue.use(Element, {
  size: Cookies.get('size') || 'medium' // set element-ui default size
})

Vue.config.productionTip = false

new Vue({
  el: '#app',
  router,
  store,
  render: h => h(App)
})