Java读取文件

BufferedReader

public static void readByBufferedReader() throws IOException {
    FileReader fileReader = new FileReader("/tmp/flag");
    BufferedReader bufferedReader = new BufferedReader(fileReader);
    String st;
    while ((st = bufferedReader.readLine()) != null) {
        System.out.println(st);
    }
}

FileReader

public static void readbyFileReader() throws IOException {
    FileReader fileReader = new FileReader("/tmp/flag");
 
    int temp;
    while ((temp = fileReader.read()) != -1) {
        System.out.print((char) temp);
    }
 
}

Scanner

public static void readByScanner() throws FileNotFoundException {
    Scanner scanner = new Scanner(new File("/tmp/flag"));
    while (scanner.hasNext()) {
        System.out.println("test");
        System.out.println(scanner.nextLine());
    }
}

File.readAllLines

public static void readByFiles() throws IOException {
    ArrayList list = (ArrayList) Files.readAllLines(Paths.get("/tmp/flag"));
    list.forEach((a) -> System.out.println(a));
}