HarmonyOS 如何在业务代码里创建Web组件以实现预加载批量URL和获取web的UserAgent给业务使用

import web_webview from '@ohos.web.webview' 
 
@Entry 
@Component 
struct Index { 
  controller: web_webview.WebviewController = new web_webview.WebviewController() 
 
  build() { 
    Tabs() { 
      TabContent() { 
        Web({ 
          src: '', 
          controller: this.controller 
        }) 
          .onControllerAttached(() => { 
            const test = this.controller.getUserAgent() 
            console.log("getUserAgent: " + test); 
            this.controller.setCustomUserAgent(test) 
            this.controller.loadUrl('https://www.huawei.com') 
          }) 
          .onPageEnd(() => { 
            const list = this.controller.getBackForwardEntries() 
            console.log("historyList: " + JSON.stringify(list)); 
          }) 
      } 
    } 
  } 
}