子组件t2

<template>
    <div>
        <p>t2</p>
    </div>
</template>
<script>
export default {
    name:'OnceT2',
    methods:{
        sayHello2(){
            console.log('sayHello2');
        }
    }
}
</script>

子组件t1

<template>
    <div>
        <p>t1</p>
    </div>
</template>
<script>
export default {
    name:'OnceT1',
    inject:['sayHello2'],//依赖注入的内容，导入父组件的某个方法
    methods:{
        sayHello1(){
            console.log('sayHello1');
        }
    },
    mounted(){
        this.sayHello2();
    }
}
</script>

父组件

<template>
 <button @click="hehe">hehe</button> 
</template>
import {OnceT1,OnceT2} from '_c/test/index.js'//导入同级组件
<script>
export default {
 provide(){//依赖注入
        return{
            sayHello2:this.hehe
        }
    },
      methods:{
        hehe(){
            this.$refs.t2.sayHello2();
        }
        }
}
</script>