**一、<router-link :to="...">\
** to里的值可以是一个字符串路径,或者一个描述地址的对象。例如:
<router-link to="apple"> to apple</router-link>\
<router-link :to="{path:'apple'}"> to apple</router-link>\
<router-link :to="{name: 'applename'}"> to apple</router-link>\
<router-link :to="{path: 'apple', query: {color: 'red' }}"> to apple</router-link>\
<router-link :to="{name: 'applename', query: {color: 'red' }}"> to apple</router-link>\
<router-link :to="{path: 'apple', params: { color: 'red' }}"> to apple</router-link>\
<router-link :to="{name: 'applename', params: { color: 'red' }}"> to apple</router-link>