借助JDK7中WatchService实现文件变更监听

ゝ一纸荒年。 2023-06-08 06:17 11阅读 0赞

import org.springframework.core.io.FileSystemResource;
    import org.springframework.core.io.support.PropertiesLoaderUtils;
    import java.io.IOException;
    import java.nio.file.*;
    import java.util.Objects;
    import java.util.Properties;
    
    
    /** * @author Created by niugang on 2019/10/16/19:41 */
    @SuppressWarnings("InfiniteLoopStatement")
    public class WatchServiceDemo { 
        private static String fileName="mail.properties";
        private static FileSystemResource classPathResource = null;
        private static WatchService watchService = null;
    
        public static Properties properties;
    
    
        static { 
    
            String filePath = "D:/home/conf/mail.properties";
            //从文件系统加载文件
            classPathResource = new FileSystemResource(filePath);
            //监听filenam所在的目录下的文件修改、删除事件
            try { 
                watchService = FileSystems.getDefault().newWatchService();
                Paths.get(classPathResource.getFile().getParent()).register(watchService,
                        StandardWatchEventKinds.ENTRY_MODIFY,
                        StandardWatchEventKinds.ENTRY_DELETE
                );
                properties = PropertiesLoaderUtils.loadProperties(classPathResource);
            } catch (IOException e) { 
                e.printStackTrace();
            }
    
    
            Thread watchThread = new Thread() { 
                @Override
                public void run() { 
    
                    while (true) { 
                        WatchKey watchKey = null;
                        try { 
                            watchKey = watchService.take();
                            for (WatchEvent<?> event : watchKey.pollEvents()) { 
                                if (Objects.equals(event.context().toString(), fileName)) { 
                                    properties = PropertiesLoaderUtils.loadProperties(classPathResource);
                                    break;
                                }
                            }
                            watchKey.reset();
                        } catch (Exception e) { 
                            e.printStackTrace();
                        } finally { 
                            if (watchKey != null) { 
                                watchKey.reset();
                            }
                        }
    
    
                    }
                }
            };
            //设置为守护线程
            watchThread.setDaemon(true);
            watchThread.start();
    
           //JVM停止时 关闭
            Runtime.getRuntime().addShutdownHook(new Thread(){ 
                @Override
                public void run() { 
                    try { 
                        watchService.close();
                    } catch (IOException e) { 
                        e.printStackTrace();
                    }
                }
            });
        }
    
    //
    // public static void main(String[] args) throws InterruptedException { 
    // //验证 启动main方法 修改mail.properties文件 看控制台输出内容的变化
    // while (true){ 
    // System.out.println(properties);
    // Thread.sleep(5000);
    // }
    //
    //
    //
    // }
    
    }

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