Java登录注册模块实现与验证方法

public boolean registerUser(String username, String password) {
    if (!isValidUsername(username) || !isValidPassword(password)) {
        throw new IllegalArgumentException("用户名或密码不符合规范");
    }

    File file = new File("users.txt");
    try (BufferedWriter writer = new BufferedWriter(new FileWriter(file, true))) {
        writer.write(username + ":" + password);
        writer.newLine();
        return true;
    } catch (IOException e) {
        throw new RuntimeException("文件写入失败，请检查权限或磁盘空间", e);
    }
}

private boolean isValidUsername(String username) {
    return username != null && username.matches("\\w{4,20}");
}

private boolean isValidPassword(String password) {
    return password != null && password.length() >= 6;
}

public boolean loginUser(String username, String password) {
    File file = new File("users.txt");
    if (!file.exists()) {
        throw new IllegalStateException("用户数据文件不存在，请先注册");
    }

    try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
        String line;
        while ((line = reader.readLine()) != null) {
            String[] parts = line.split(":");
            if (parts.length == 2 && parts[0].equals(username) && parts[1].equals(password)) {
                return true;
            }
        }
        return false;
    } catch (IOException e) {
        throw new RuntimeException("读取用户数据失败", e);
    }
}