每100行向文件写入一行

Question

以下是我的代码，它从文件中读取了20万行。

含有正确的URL代码的那行写进了 true.txt 和包含错误的URL代码的行写进到 wrong.txt.

代码在读取所有行的时候，都会写入这些文件。我想做一个小改动。当代码读完一百行时，它就会更新错误的和真实的。file.txt. 任何一个人指导我如何是可能的？

public static void main(String[] args) throws IOException {
    int coded = 0;
    int counter = 0;
    int timeout = 0;
    boolean canConnect = false;
    Scanner in = new Scanner(System.in);
    System.out.print("Enter the file name:");
    String filename = in .nextLine();

    BufferedReader br = null;
    FileWriter fw = null;
    FileWriter ft = null;
    String f = "truefile.txt";
    String strLine = "";

    br = new BufferedReader(new FileReader(filename));
    fw = new FileWriter("wrongfile.txt");
    ft = new FileWriter(f);

    while ((strLine = br.readLine()) != null) {

        System.out.println(strLine);
        if (strLine.contentEquals("arrow-uee.com")) {
            System.out.println("timeout");
        } else {
            try {
                URL u = new URL("http://" + strLine);
                HttpURLConnection huc = (HttpURLConnection) u.openConnection();
                huc.setUseCaches(false);
                huc.setConnectTimeout(timeout);
                huc.setRequestMethod("GET");

                coded = huc.getResponseCode();

                if (coded == HttpURLConnection.HTTP_OK) {
                    canConnect = true;
                }
                int code = coded / 100;
                if (code == 4 || code == 5 || coded == 303) {
                    fw.write(strLine + ":error:" + coded + "\n" + "\n");
                    System.out.println("domain is not ok error:" + coded);
                } else {
                    ft.write(strLine + "\n" + "\n");
                    System.out.println("domain is ok:");
                }
                counter++;
                System.out.println("total domain checked:" + counter);
            } catch (FileNotFoundException e) {
                System.err.println("File not found");
            } catch (IOException e) {
                System.out.println("domain not exist fatal error");
            }
        }

    }
    br.close();
    ft.close();
    fw.close();
}

Answer 1

这是你的答案，只要加上flush

public static void main(String[] args) throws IOException {
int coded = 0;
int counter = 0;
int timeout = 0;
boolean canConnect = false;
Scanner in = new Scanner(System.in);
System.out.print("Enter the file name:");
String filename = in .nextLine();

BufferedReader br = null;
FileWriter fw = null;
FileWriter ft = null;
String f = "truefile.txt";
String strLine = "";

br = new BufferedReader(new FileReader(filename));
fw = new FileWriter("wrongfile.txt");
ft = new FileWriter(f);

while ((strLine = br.readLine()) != null) {

    System.out.println(strLine);
    if (strLine.contentEquals("arrow-uee.com")) {
        System.out.println("timeout");
    } else {
        try {
            URL u = new URL("http://" + strLine);
            HttpURLConnection huc = (HttpURLConnection) u.openConnection();
            huc.setUseCaches(false);
            huc.setConnectTimeout(timeout);
            huc.setRequestMethod("GET");

            coded = huc.getResponseCode();

            if (coded == HttpURLConnection.HTTP_OK) {
                canConnect = true;
            }
            int code = coded / 100;
            if (code == 4 || code == 5 || coded == 303) {
                fw.write(strLine + ":error:" + coded + "\n" + "\n");
                System.out.println("domain is not ok error:" + coded);
            } else {
                ft.write(strLine + "\n" + "\n");
                System.out.println("domain is ok:");
            }
            counter++;
            System.out.println("total domain checked:" + counter);
        } catch (FileNotFoundException e) {
            System.err.println("File not found");
        } catch (IOException e) {
            System.out.println("domain not exist fatal error");
        }
    }
  ft.flush();
   fw.flush();
 }
br.close();
ft.close();
fw.close();