Question

我在下面的程序中没有在指定的时间段内选择文件，请更新..其中有错误..

import java.io.BufferedReader;
import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Calendar;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class PatternFileFilter implements FileFilter {

    public static String ITEM_TYPE_FILE = "File"; // for file

    public static String ITEM_TYPE_FOLDER = "Folder"; // for folder

    public static String ITEM_TYPE_FILE_AND_FOLDER = "FileAndFolder"; // for file and folder

    private Pattern fileNamePattern;

    public PatternFileFilter(Pattern fileNamePattern) {
        this.fileNamePattern = fileNamePattern;
    }

    public boolean accept(File pathname) {
        return fileNamePattern.matcher(pathname.getName()).find() || pathname.isDirectory();
    }

    public Pattern getPattern() {
        return fileNamePattern;
    }

    public static void searchFile(File topFolderOrFile, String type, PatternFileFilter filter, long timeOut) throws IOException {

        long startTimeStamp = Calendar.getInstance().getTimeInMillis();
        if (topFolderOrFile.isDirectory()) {
            File[] subFoldersAndFileNames = topFolderOrFile.listFiles(filter);
            if (subFoldersAndFileNames != null && subFoldersAndFileNames.length > 0) {
                for (File subFolderOrFile : subFoldersAndFileNames) {
                    if (ITEM_TYPE_FILE.equals(type) && subFolderOrFile.isFile()) {
                        System.out.println("File name matched ----- " + subFolderOrFile.getName());
                    }
                    if (ITEM_TYPE_FOLDER.equals(type) && subFolderOrFile.isDirectory()
                            && filter.getPattern().matcher(subFolderOrFile.getName()).find()) {

                        System.out.println("Folder name matched ----- " + subFolderOrFile.getName());
                    }

                    if (ITEM_TYPE_FILE_AND_FOLDER.equals(type) && filter.getPattern().matcher(subFolderOrFile.getName()).find()) {
                        System.out.println("File or Folder name matched ----- " + subFolderOrFile.getName());

                    }
                    // You need to decide if you want to process the folders inline // or after you've processed the
                    // file list...
                    if (subFolderOrFile.isDirectory()) {
                        long timeElapsed = startTimeStamp - Calendar.getInstance().getTimeInMillis();
                        if (((timeOut * 1000) - timeElapsed) < 0) {
                            System.out.println("Could not complete operation-- timeout");
                        } else {
                            searchFile(subFolderOrFile, type, filter, (timeOut * 1000) - timeElapsed);
                        }
                    }
                }
            }
        }
    }

    public static void searchFile(String topFolderName, String type, String fileNamePatternRegExp, long timeOut)
            throws IOException {
        File topFolderOrFile = new File(topFolderName);
        Pattern fileNamePattern = Pattern.compile(fileNamePatternRegExp);
        searchFile(topFolderOrFile, type, new PatternFileFilter(fileNamePattern), timeOut);
    }

    // ***************
    public static void main(String[] str) throws Exception {

        System.out.println("Type Item to Search ");
        System.out.println("1 File");
        System.out.println("2 Folder ");
        System.out.println("3 Both");
        System.out.println("0 Exit");

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        String searchType = br.readLine();

        System.out.println("Enter top folder name ::");

        String topFolderName = br.readLine();

        System.out.println("Enter name of file to search ::");

        String fileName = br.readLine();

        System.out.println("Enter timeout period in seconds::");

        String timeOutStr = br.readLine();

        if (searchType == null || fileName == null || topFolderName == null || timeOutStr == null) {
            throw new Exception("Error Occured::Provide both the input Parameters");
        }

        int searchTypeInd = Integer.parseInt(searchType);
        switch (searchTypeInd) {

        case 1:
            searchFile(topFolderName, ITEM_TYPE_FILE, fileName, Long.parseLong(timeOutStr));
            break;

        case 2:
            searchFile(topFolderName, ITEM_TYPE_FOLDER, fileName, Long.parseLong(timeOutStr));
            break;
        case 3:
            searchFile(topFolderName, ITEM_TYPE_FILE_AND_FOLDER, fileName, Long.parseLong(timeOutStr));
            break;

        case 0:
            System.exit(0);
        }

    }

}

请告知我D：\ saral中是否有文件夹，应该从D：文件夹中选择文件

我得到的结果是......

键入要搜索的项目1文件2文件夹3两者0退出3输入顶级文件夹   name :: Test输入要搜索的文件名:: allMfile.txt输入   超时时间（秒）:: 5

Answer 1

我猜这是错的：

searchFile(subFolderOrFile, type, filter, (timeOut * 1000) - timeElapsed);
                                                  ^^^^^^^

看起来你混合了时间单位：你期望秒，但是传递毫秒值。在你的情况下，你传递的第一个超时等于5秒，在第一次递归中，你传递5000秒，在下一级传递1000次......

提示：将方法参数重命名为timeOutInSeconds并再次读取您的代码。

Answer 2

我建议颠倒逻辑。而不是传递超时（并进行复杂的计算），计算方法之外的结束时间：

long timeOut = System.currentTimeMillis() + Long.parseLong(timeOutStr);

在该方法中，您可以使用以下方法检查超时：

if( System.currentTimeMillis() > timeOut ) { break; }

您也不会在代码中结束循环（使用break或return），因此检查超时只会阻止递归调用。

最后，请考虑反转您的if()条件而不是嵌套它们：

if (!topFolderOrFile.isDirectory()) { return; }

File[] subFoldersAndFileNames = topFolderOrFile.listFiles(filter);
if (subFoldersAndFileNames == null || subFoldersAndFileNames.length == 0) { return; }

...

没有选择文件

2 个答案: