HarmonyOS选取并拷贝文件失败

import picker from '@ohos.file.picker'; 
import fs from '@ohos.file.fs'; 
@Entry 
@Component 
struct Index { 
  build() { 
    Row() { 
      Column() { 
        Button("copyFile") 
          .onClick(async () => { 
            try { 
              const photoSelectOptions = new picker.PhotoSelectOptions(); 
              photoSelectOptions.MIMEType = picker.PhotoViewMIMETypes.IMAGE_TYPE; 
              photoSelectOptions.maxSelectNumber = 1; 
              const photoPicker = new picker.PhotoViewPicker(); 
              const photoSelectResult = await photoPicker.select(photoSelectOptions); 
              const uri = photoSelectResult.photoUris[0]; 
              const url = getContext().cacheDir + '/image.jpg'; 
              await fs.copyFile(uri, url, 0); 
              console.info("copyFile succeed"); 
            } catch (error) { 
              console.info("copyFile failed", error); 
            } 
          }) 
      } 
      .width('100%') 
    } 
    .height('100%') 
  } 
}