题目1请使用匿名Runnable子类的方式实现线程线程中计算1--500所有数字的累加和并打印计算结果题目2请使用继承Thread类的方式定义一个线程类在run方法中循环10次每1秒循环1次每次循环按yyyy­MM­dd HHmmss的格式打印当前系统时间。请定义测试类并定义main方法启动此线程观察控制台打印。题目3请使用代码描述1 写一个方法实现用户登陆传入用户名和密码2 如果用户名错误就抛出

题目1

public class Main {
    public static void main(String[] args) {
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                int sum = 0;
                for (int i = 1; i <= 500; i++) {
                    sum += i;
                }
                System.out.println("1--500所有数字的累加和为：" + sum);
            }
        });
        thread.start();
    }
}

题目2

public class MyThread extends Thread {
    @Override
    public void run() {
        DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        for (int i = 1; i <= 10; i++) {
            System.out.println(dateFormat.format(new Date()));
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

public class Main {
    public static void main(String[] args) {
        MyThread myThread = new MyThread();
        myThread.start();
    }
}

题目3

public class LoginException extends Exception {
    public LoginException(String message) {
        super(message);
    }
}

public class Main {
    public static void main(String[] args) {
        try {
            login("admin", "123");
        } catch (LoginException e) {
            e.printStackTrace();
        }
    }

    public static void login(String username, String password) throws LoginException {
        if (!"admin".equals(username)) {
            throw new LoginException("用户名不存在");
        }
        if (!"admin".equals(password)) {
            throw new LoginException("密码错误");
        }
        System.out.println("欢迎" + username);
    }
}
``