/** * WatchService实现配置文件变更监听 *  */public class WatchProperties {        private static WatchService watchService;    private static String filename;    private static Properties properties;    private static ClassPathResource resource;    static {                try {            //读取的配置文件，在资源文件夹下就行            filename = "sysconst.properties";            resource = new ClassPathResource(filename);            //监听filename所在目录下的文件修改、删除事件            watchService = FileSystems.getDefault().newWatchService();            Paths.get(resource.getFile().getParent()).register(watchService,                    StandardWatchEventKinds.ENTRY_MODIFY, StandardWatchEventKinds.ENTRY_DELETE);            properties = PropertiesLoaderUtils.loadProperties(resource);        } catch(IOException e) {            e.printStackTrace();        }                //启动一个线程监听内容变化，并重新载入配置        Thread watchThread = new Thread() {            public void run() {                while(true) {                    try {                        WatchKey watchKey = watchService.take();                        for (WatchEvent event : watchKey.pollEvents()) {                            if (Objects.equals(event.context().toString(), filename)){                                properties = PropertiesLoaderUtils.loadProperties (resource);                                break;                            }                             watchKey.reset();                        }                    } catch (Exception e) {                                            }                }            };        };                        //设置成守护进程            watchThread.setDaemon(true);        watchThread.start();                //当服务器进程关闭时把监听线程close掉        Runtime.getRuntime().addShutdownHook(new Thread() {                        @Override            public void run() {                try{                    watchService.close();                } catch(IOException e) {                    e.printStackTrace();                }            }        });                                    }        public static String get(String key){        return properties.getProperty(key, "");    }        public static void main(String[] args) {        System.out.println(">>>>>>>>>>>>>>" + get("OSS_OUT_OF_DATE"));    }}