HarmonyOS 有秒级时间戳 ，怎么根据传入的fortmatStr 输出时间字符串？

import systemDateTime from '@ohos.systemDateTime'; 
import { BusinessError } from '@ohos.base'; 
 
@Entry 
@Component 
struct Index5 { 
 @State timeStr: string = ''; 
 
 build() { 
  Flex( 
   { direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) { 
   Text(`当前时间：` + this.timeStr) 
    .fontSize(20) 
    .fontWeight(FontWeight.Bold) 
   Button("get time") 
    .width(100) 
    .height(100).onClick(() => { 
    //同步方法获取系统时间戳 
    try { 
     let time = systemDateTime.getTime(false) 
     this.timeStr = this.getTimeToYYYYDDMMHHMMSS(time) 
    } catch (e) { 
     let error = e as BusinessError; 
     console.info(`Failed to get time. message: ${error.message}, code: ${error.code}`); 
    } 
    //异步方法获取系统时间戳 
    try { 
     systemDateTime.getCurrentTime(false, (error, time) => { 
      if (error) { 
       console.info(`Failed to get currentTime. message: ${error.message}, code: ${error.code}`) 
       return; 
      } 
      console.info(`Succeeded in getting currentTime : ${time}`); 
      this.timeStr = this.getTimeToYYYYDDMMHHMMSS(time) 
     }) 
     AlertDialog.show({ message: 'sss' }); 
    } catch (e) { 
     console.info(`Failed to get currentTime. message: ${e.message}, code: ${e.code}`); 
    } 
   }) 
  } 
  .width('100%') 
  .height('100%') 
 }