1. 1. 加载渲染过程
      父beforeCreate->父created->父beforeMount->子beforeCreate->子created->子beforeMount->子mounted->父mounted
   2. 子组件更新过程
      父beforeUpdate->子beforeUpdate->子updated->父updated
   3. 父组件更新过程
      父beforeUpdate->父updated
   4. 销毁过程
      父beforeDestroy->子beforeDestroy->子destroyed->父destroyed