如何理解Vue中的事件处理和事件修饰符

 <div id="root">
        <h3>{{name}}，加油！</h3>
        <!-- 阻止默认事件 -->
        <a @click.prevent="showInfo" href="https:www.baidu.com">点我提示信息</a>
        <!-- 阻止事件冒泡 -->
        <div class="demo1" @click="showInfo">
            <button @click.stop="showInfo">点我提示信息</button>
        </div>
        <!-- 事件只触发一次 -->
        <button @click.once="showInfo">点我提示信息</button>
        <!-- 使用事件捕获模式 -->
        <div class="box1" @click.capture="showMsg(1)">
            div1
            <div class="box2" @click="showMsg(2)">
                div2
            </div>
        </div>
        <!-- 只有event.target是当前操作的元素时才触发事件  -->
        <div class="demo1" @click.self="showInfo">
            <button @click="showInfo">点我提示信息</button>
        </div>
    </div>
    <script>
        Vue.config.productionTip = false;
        new Vue({
            el: '#root',
            data() {
                return {
                    name: '张三'
                }
            },
            methods: {
                showInfo(e) {
                    //  e.preventDefault();
                    alert('王同学，你好！')
                },
                showMsg(msg) {
                    console.log(msg);
                }
            }
        });
    </script>