求大佬告知webview如何设置UA

// xxx.ets 
import web_webview from '@ohos.web.webview' 
import business_error from '@ohos.base' 
  
@Entry 
@Component 
struct WebComponent { 
  controller: web_webview.WebviewController = new web_webview.WebviewController(); 
  @State customUserAgent: string = 'test' 
  
  build() { 
    Column() { 
      Web({ src: 'www.example.com', controller: this.controller }) 
        .onControllerAttached(() => { 
             let userAgent = this.controller.getUserAgent() + this.customUserAgent; 
           //设置自定义UA 
            this.controller.setCustomUserAgent(userAgent); 
           //获取自定义UA 
            console.log("userAgent: " + this.controller.getCustomUserAgent()); 
        }) 
    } 
  } 
}