JAVA编程题之用户登录,用户信息存储在本地文件

实现用户登录：键盘输入要登录的用户名与密码

properties类型文件常在框架内用作配置文件.

public static void main(String[] args) throws Exception {
    FileInputStream fis = new FileInputStream("user.properties");
    Properties properties = new Properties();
    properties.load(fis);
    Set<String> strings = properties.stringPropertyNames();
    System.*out*.println(strings);
    Scanner scanner = new Scanner(System.*in*);
    System.*out*.println("请输入用户名");
    String userName = scanner.next();
    if (properties.getProperty(userName) == null) {
        System.*out*.println("用户未注册,请先注册!");
    System.*exit*(0);
    }
    
​    System.*out*.println("请输入密码");
​    int i = 0;
​    do {
​        String passWord = scanner.next();

​            if (properties.getProperty(userName).equals(passWord)) {
​                System.*out*.println("成功登录");
​                break;
​            } else {
​                if (2 - i == 0) {
​                    System.*out*.println("忘记密码?请按要求找回密码");
​                } else {
​                    System.*out*.println("密码错误，请重新输入,还有" + (2 - i) + "机会");
​                }
​            }

​    } while (++i < 3);
​    fis.close();
}

文件内容如下