Java 定时任务：每天执行代码示例

public class TimerExample {\n public static void main(String[] args) {\n // 创建定时器任务\n TimerTask timerTask = new TimerTask() {\n @Override\n public void run() {\n System.out.println("Hello world!");\n }\n };\n\n // 获取当前时间\n Calendar calendar = Calendar.getInstance();\n Date currentTime = calendar.getTime();\n\n // 设置每天定时执行的时间（例如：每天的 9:00 AM）\n calendar.set(Calendar.HOUR_OF_DAY, 9);\n calendar.set(Calendar.MINUTE, 0);\n calendar.set(Calendar.SECOND, 0);\n calendar.set(Calendar.MILLISECOND, 0);\n\n // 如果当前时间已经超过了设置的执行时间，则将执行时间延迟到明天的相同时间\n if (currentTime.after(calendar.getTime())) {\n calendar.add(Calendar.DAY_OF_MONTH, 1);\n }\n\n // 计算延迟时间\n long initialDelay = calendar.getTimeInMillis() - currentTime.getTime();\n\n ScheduledExecutorService scheduledThreadPool = Executors.newScheduledThreadPool(2);\n\n // 每天定时执行\n scheduledThreadPool.scheduleAtFixedRate(timerTask, initialDelay, 24 * 60 * 60 * 1000, TimeUnit.MILLISECONDS);\n }\n}