Imagine a scenario in which you want to traverse a directory tree recursively, stopping at each file and directory under that tree and having your own callback methods invoked for each entry found.

设想一个场景，您想要递归地访问一个目录树，在该树中的每个文件及目录上停下来，并为每个查找到的条目调用您自己的回调方法。

youdao

In this step, you will traverse the source file system tree.

在这个步骤中，您将遍历源文件系统树。

youdao

However, three methods also need to traverse each file, similar methods 2 and relatively time-consuming.

然而方法3也需要遍历每个文件，因此类似方法2，也比较耗时。

youdao

However, three methods also need to traverse each file, similar methods 2 and relatively time-consuming.

然而方法3也需要遍历每个文件，因此类似方法2，也比较耗时。

youdao