配置store

import Vue from 'vue'
import Vuex from 'vuex'


//相当于java里面创建实体类
Vue.use(Vuex);
export default new Vuex.Store({
    //状态
    state: {
        //从localStorage里面获取值
        userinfo: JSON.parse(localStorage.getItem("userinfo "))
        // userinfo: localStorage.getItem("userinfo ")
    },
    mutations: {
        //从一些方法里面创建axios中获取数据放进这个变量里面，如果是对象的话要转换json
        SET_USERINFO: (state, userinfo) => {
            state.userinfo = userinfo;
            localStorage.setItem("userinfo ", JSON.stringify(userinfo));
        }
    },
    //创建get方法  让其他方法获得state状态，这个状态里面拥有数据
    getters: {
        getUser: state => {
            return state.userinfo;
        }
    },
    // actions: {},
    // modules: {}
});

然后需要在main.js里面注册

new Vue({
    render: h => h(App), //跳到视图的展示vue
    // 主函数调用路由
    router,
    store,
}).$mount('#app')
//=== el:"#app",也就是挂载到id为app的标签里面

配置页面，进行后端存值

<template>
  <el-form
      :model="user"
      :rules="rules"
      ref="user"
      label-width="100px"
      class="logintest-ruleForm"
  >
    <el-form-item label="账号" prop="name">
      <el-input v-model="user.name"></el-input>
    </el-form-item>
    <el-form-item label="密码" prop="password">
      <el-input v-model="user.password" type="password"></el-input>
    </el-form-item>
    <el-form-item>
      <el-button type="primary" @click="submitForm('user')"
      >登录
      </el-button
      >
      <el-button @click="resetForm('user')">重置</el-button>
    </el-form-item>
  </el-form>
</template>

<script>

export default {
  name: "loginTest",

  data() {
    return {
      user: {
        name: '',
        password: '',
      },

      rules: {
        name: [
          {required: true, message: '请输入账号', trigger: 'blur'},
          {
            min: 3,
            max: 5,
            message: '长度在 3 到 5 个字符',
            trigger: 'blur',
          },
        ],
        password: [
          {required: true, message: '请输入密码', trigger: 'blur'},
          {
            min: 3,
            max: 5,
            message: '长度在 3 到 5 个字符',
            trigger: 'blur',
          },
        ],
      },
    }
  },


  methods: {
    submitForm(formName) {
      this.$refs[formName].validate((valid) => {
        if (valid) {
          // alert('submit!')
          this.$axios.post('/mybatis_plus/user/getUser', this.user).then(response => {
                //把返回的值放进store里面 
                this.$store.commit("SET_USERINFO", response.data)
                alert(response.data)
                alert(response.data.name)
                alert(response.data.password)
                // if (response.data.eq('fail')){
                //   this.$router.replace("/loginTest")
                // }
                  this.$router.replace("/index")
              }
          )
          //  业务逻辑  登录业务，向后端请求端口
        } else {


          return false
        }
      })
    },
    resetForm(formName) {
      this.$refs[formName].resetFields()
    },
  }
}

</script>

<style scoped>
.logintest-ruleForm {
  margin: auto;
  width: 40%;
  /*border: 3px solid green;*/
  padding: 10px;
}

</style>

进行前端取值，把值放进usesrinfo里面，因为只是存一个值，所以收到的是一个对象的json。

  data() {
    return {
      userinfo: '',
    }
  },
  methods: {
    getUser() {
      this.userinfo = this.$store.getters.getUser;
    }
  },
  created() {
    this.getUser();
  }