[問題] 如何加快搜尋效率
各位前輩好，小弟有一支搜尋Google Drive的程式
因為使用者通常不知道folder id，所以預設的搜尋位置是從根目錄(root)開始搜尋檔案
我採用的是深度優先搜尋法(DFS)，也就是搜尋到的檔案如果是資料夾
那麼接著就開始搜尋該資料夾下的檔案，以此類推
如果要搜尋的檔案在很前面 (不清楚一開始搜尋的資料夾是依據什麼)，
那麼該檔案就很有可能被找到
反之，就有可能回傳 HTTP 500 Internal Server Error(應該是Time out)
程式碼如下，是使用遞迴搜尋：
... 省略 ...
service = new Drive.Builder(httpTransport, JSON_FACTORY, credential)
.setApplicationName(APPLICATION_NAME).build();
System.out.println("=== Start to search ===");
long startTime = System.currentTimeMillis();
File searchResult = recursiveSearch(folderID, searchFileName);
if (searchResult != null) {
result = searchResult.getName();
// 結束時間
long endTime = System.currentTimeMillis();
long totTime = (endTime - startTime) / 1000;
// 印出花費時間
System.out.println("花費時間:" + totTime + "秒");
}
public File recursiveSearch(String folderID, String searchFileName) throws
IOException {
File searchResult = null;
FileList fileList = service.files().list()
.setQ("'" + folderID + "' in parents and trashed = false")
// .setSpaces("drive")
.setCorpora("user")
.setFields("nextPageToken, files(id, name, mimeType)").execute();
List<File> items = fileList.getFiles();
System.out.println("files size is " + items.size());
for (File file : items) {
if (file.getName().equals(searchFileName)) {
searchResult = file;
System.out.println(file.getName() + " is found!");
return searchResult;
} else if (file.getMimeType().equals("application/vnd.google-apps
.folder"))
{
System.out.println("recursive search");
System.out.println("file.getId() is " + file.getId());
searchResult = recursiveSearch(file.getId(), searchFileName);
} else {
System.out.println("file name is " + file.getName());
}
if (searchResult != null) {
System.out.println("Finish");
break;
}
}
return searchResult;
}
public static void main(String[] args) throws IOException {
DriveSearch driveSearch = new DriveSearch();
String result = driveSearch.fetchData("hfjBV5Z3V2c", "test.txt");
System.out.println(result);
}
在Google Drive上面的根目錄搜尋同樣檔案一下子就找到了，
所以是演算法的問題嗎？
程式該怎麼改寫才能增進搜尋效率？
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※ 編輯: FacetheFaith (59.124.165.65), 09/20/2017 16:58:17
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