java - 读取文件的递归方法不起作用

Question

我这里有这个方法，我想递归地查找文件夹以计算以“D”开头的文件。

它向我展示了StackOverflowError。

public void CountThem() throws FileNotFoundException, IOException{
           int count = 0;
        File []files = file.listFiles();

        for(File f : files){
            if(f.isDirectory()){
                CountThem();
            }else{
                if(f.getName().startsWith("D")){
                    count++;
                }
            }
        }
    }

Answer 1

这是因为当 File 是一个目录时，您将重新开始您的函数，这会导致无限循环。您必须定义以 File 作为参数的函数:

public int countThem(File file) throws FileNotFoundException, IOException{
    int count = 0;
    File []files = file.listFiles();

    for(File f : files){
        if(f.isDirectory()) {
            count += countThem(f);
        } else {
            if(f.getName().startsWith("D")) {
                count++;
            }
        }
    }

    return count;
}

P.S.:在java中，方法名称以小写开头是一个标准。

编辑:

public class Fajlla {

    File folder;
    FileReader fr;
    BufferedReader br;
    PrintWriter pw;
    public Fajlla(String fld)throws IOException{
        folder = new File(fld);
        if(!folder.isDirectory()){
            throw new IOException("Nuk eshte folder");
        }
        pw = new PrintWriter(new File("C:/Users/Admin/Desktop/dreniii.txt"));
    }

        public int callItOUU() throws IOException{
            return this.countThem(folder);
        }


    public int countThem(File folder){
           int count = 0;
            File [] files = folder.listFiles();
            for (File file : files) {
                  if(file.isDirectory()){
                      count+=countThem(file);
                  }if(file.isFile() && file.canRead()){
                      count++;
                  }
        }
            return count;
    }




        public static void main(String[] args) {

        try {

            Fajlla  f = new Fajlla("C:/Users/Admin/Desktop/New folder");
            int count = f.callItOUU(new File("C:/Users/Admin/Desktop/dreniii.txt"));
            System.out.println(count);
        } catch (IOException ex) {
            Logger.getLogger(Fajlla.class.getName()).log(Level.SEVERE, null, ex);
        }

    }


}