vue-如何用全局变量填写后端地址

global
  
  
  
  main.js
  import global_ from './components/Global'//引用文件
  Vue.prototype.GLOBAL = global_//挂载到Vue实例上面
  html
show() {
      var vm = this;
      let tempUrl = this.GLOBAL.serverSrc;
      const url = tempUrl + "/selectParticipantObject";
      this.$axios
        .get(
          url,
          {}
        )
        .then(res => {
          console.log(res.data.data.projectList);
          //插入一级标题
          vm.$set(this.listOne, 0, res.data.data.listLine[0].lineName);
          vm.$set(this.listOne, 1, "英语");
          //插入二级标题
          vm.$set(
            this.listTwo,
            0,
            res.data.data.listLine[0].listOne[0].parentName
          );
          //插入三级标题
          vm.$set(
            this.listThree,
            0,
            res.data.data.listLine[0].listOne[0].listTwo[0].childName
          );
        })
        .catch(err => {
          console.log(err);
        });
    },