Java-递归获取目录和子目录中的所有文件

Question

这里有些曲折。 我正在使用的不是本地目录。 我正在尝试为此链接创建一个批量下载器：

https://files.secureserver.net/0fHCh0CLd6Az63
https://files.secureserver.net/0fdAWETp4sONW5

在这里，每个文件和文件夹都分配有唯一的ID。

-我的目标是从所有目录和子目录中获取所有文件ID。

如果我有ID，就可以下载文件并查看文件夹的内容。

所以问题是，当我获取目录的内容时，它们在其中包含子目录。

那么，如何递归获取这些目录和子目录中的所有文件ID？
可以用树数据结构解决吗，或者有什么简单的方法吗？

这是我的代码：

    package javaapplication1;

    import java.io.IOException;
    import java.util.Iterator;
    import java.util.TreeSet;
    import org.jsoup.Connection;
    import org.jsoup.Jsoup;
    import org.jsoup.nodes.Document;
    import org.jsoup.nodes.Element;
    import org.jsoup.select.Elements;

    public class GoDaddyDownloader2 {

        Document document;
        String openFolderUrl;
        String downloadFileUrl;
        String frameSrc;
        TreeSet folderTreeSet;
        TreeSet fileTreeSet;
        StringBuilder fileId;
        StringBuilder folderId;

        public GoDaddyDownloader2() {
            openFolderUrl = "";
            downloadFileUrl = "";
            frameSrc = "";
            folderTreeSet = new TreeSet();
            fileTreeSet = new TreeSet();
            fileId = new StringBuilder();
            folderId = new StringBuilder();
        }

        public void getUrl(String url) throws IOException {
            document = Jsoup.connect(url)
                    .userAgent("Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0")
                    .get();
            frameSrc = document.getElementsByTag("iframe").attr("src");
            openFolderUrl = frameSrc.replace("display_folder", "get_listing");
            openFolderUrl = openFolderUrl.replace("public_folder", "public_folder_ajax");
            downloadFileUrl = frameSrc.replace("display_folder", "get_download_url");

            System.out.println(frameSrc);
            System.out.println(openFolderUrl);
            System.out.println(downloadFileUrl);
            getRootFolder();

        }

        public void getRootFolder() throws IOException {

            document = Jsoup.connect(frameSrc)
                    .userAgent("Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0")
                    .get();

            getFileAndFilders();

            //getFolderById("686499839");
        }

        public void getFileAndFilders() {
            Elements mapElements = document.getElementsByTag("map");

            for (Element temp : mapElements) {
                //System.out.println(StringEscapeUtils.unescapeHtml4(temp.toString()));
                if (!temp.attr("folder_id").toString().contentEquals("")) {
    //                System.out.println("====>"  + temp.attr("folder_id").toString());
                    if (temp.attr("folder_id").toString().contains("\"")) {
                        folderId = new StringBuilder(temp.
                                attr("folder_id").toString().
                                substring(temp.attr("folder_id").toString().
                                        indexOf("\"") + 1,
                                        temp.attr("folder_id").toString().
                                        lastIndexOf("\"") - 1));
    //                    System.out.println(folderId);
                    } else {
                        folderTreeSet.add(temp.attr("folder_id").toString());
                    }
                } else if (!temp.attr("file_id").toString().contentEquals("")) {
    //                System.out.println("++++>"  + temp.attr("file_id").toString());
                    if (temp.attr("file_id").toString().contains("\"")) {
                        fileId = new StringBuilder(temp.
                                attr("file_id").toString().
                                substring(temp.attr("file_id").toString().
                                        indexOf("\"") + 1,
                                        temp.attr("file_id").toString().
                                        lastIndexOf("\"") - 1));
                        fileTreeSet.add(fileId.toString());
    //                    System.out.println(fileId);
                    } else {
                        fileTreeSet.add(temp.attr("file_id").toString());
                    }

                }
            }
        }

        public void getFolderById(String fid) throws IOException {
            document = Jsoup.connect(openFolderUrl)
                    .userAgent("Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0")
                    .data("folder_id", fid)
                    .data("open_folder_id", "")
                    .data("view", "list")
                    .data("column_number", "0")
                    .data("sort_term", "name")
                    .data("sort_direction", "asc")
                    .data("offset", "0")
                    .method(Connection.Method.POST)
                    .execute().parse();

            getFileAndFilders();
        }

        public String downloadFileById(String fileId) throws IOException {

            String link = Jsoup.connect(downloadFileUrl)
                    .userAgent("Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0")
                    .data("file_id", fileId)
                    .method(Connection.Method.POST)
                    .execute().parse().text();
            System.out.println(link);
            return link;
        }

        public static void main(String[] args) throws IOException {
            GoDaddyDownloader2 obj = new GoDaddyDownloader2();
            obj.getUrl("https://files.secureserver.net/0fHCh0CLd6Az63");

            //Contents of root directory
            Iterator i = obj.folderTreeSet.iterator();
            System.out.println("Folders");
            while (i.hasNext()) {
                String s = (String) i.next();
                System.out.println(s);
            }
            System.out.println("---------------");
            System.out.println("Files");
            i = obj.fileTreeSet.iterator();
            while (i.hasNext()) {
                String s = (String) i.next();
                System.out.println(s);
            }
            System.out.println("===============");

            //Adding Contents of first directory to TreeSet
            System.out.println("After adding contents of first directory");
            obj.getFolderById(obj.folderTreeSet.first().toString());
            System.out.println("Folders");
            i = obj.folderTreeSet.iterator();
            while (i.hasNext()) {
                String s = (String) i.next();
                System.out.println(s);
            }
            System.out.println("---------------");
            System.out.println("Files");
            i = obj.fileTreeSet.iterator();
            while (i.hasNext()) {
                String s = (String) i.next();
                System.out.println(s);
            }

            System.out.println("Generate file link");
            obj.downloadFileById(obj.fileTreeSet.first().toString());

        }
    }

我正在使用TreeSet来避免重复。

Answer 1

答案就出在问题上：由于您要递归执行某项操作，因此显而易见的方法是使用递归。 类似于以下伪代码：

public Set<Thing> downloadEverything(Directory directory) {
    Set<Thing> result = new HashSet<>();
    downloadEverything(directory, result);
}

private void downloadEverything(Directory directory, Set<Thing> result) {
    for (File file : getFilesOfDirectory() {
        result.add(downloadThingFromFile(file));
    }
    for (Directory subDirectory : getSubdirectoriesOfDirectory(directory) {
        downloadEverything(subDirectory, result);
    }
}

private Thing downloadThingFromFile(File file) {
    // ...
}