首先说下需求:通过ftp上传约定格式的文件到服务器指定目录下,应用程序能实时监控该目录下文件变化,如果上传的文件格式符合要求,将将按照每一行读取解析再写入到数据库,解析完之后再将文件改名。
设置一个定时任务,每隔一分钟读取下指定目录下的文件变化,如果有满足格式的文件,就进行解析。
这种方式很繁琐,而且效率低,效率都消耗在了遍历、保存状态、对比状态上了! 而且无法利用OS的很多功能。
1、 该类的对象就是操作系统原生的文件系统监控器!我们都知道OS自己的文件系统监控器可以监控系统上所有文件的变化,这种监控是无需遍历、无需比较的,是一种基于信号收发的监控,因此效率一定是最高的;现在Java对其进行了包装,可以直接在Java程序 中使用OS的文件系统监控器了;
2、 获取当前OS平台下的文件系统监控器:
i. WatchService watcher = FileSystems.getDefault().newWatchService();
ii. 从FileSystems这个类名就可以看出这肯定是属于OS平台文件系统的,接下来可以看出这一连串方法直接可以得到一个文件监控器;
这里暂时不用深入理解这串方法的具体含义,先知道怎么用就行了;
3、 我们都知道,操作系统上可以同时开启多个监控器,因此在Java程序中也不例外,上面的代码只是获得了一个监控器,你还可以用同样的代码同时获得多个监控器;
4、 监控器其实就是一个后台线程,在后台监控文件变化所发出的信号,这里通过上述代码获得的监控器还只是一个刚刚初始化的线程,连就绪状态都没有进入,只是初始化而已;
其实就是在初始化的时候创建一个线程,然后用watchService实时监控该目录下文件变化,如果有满足条件文件加进来,就按照约定的格式解析文件再写入数据库,详细步骤如下!
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ThreadStartUpListenser.java
package com.zealer.ad.listener;import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.springframework.stereotype.Component;import com.zealer.ad.task.WatchFilePathTask; @Componentpublic class ThreadStartUpListenser implements ServletContextListener {private static WatchFilePathTask r = new WatchFilePathTask();private Log log = LogFactory.getLog(ThreadStartUpListenser.class); /* * tomcat启动的时候创建一个线程 * */@Overridepublic void contextInitialized(ServletContextEvent paramServletContextEvent) { r.start(); log.info("ImportUserFromFileTask is started!"); } /* * tomcat关闭的时候销毁这个线程 * */@Overridepublic void contextDestroyed(ServletContextEvent paramServletContextEvent) { r.interrupt(); } }
WatchFilePathTask.java
WatchFilePathTask Log log = LogFactory.getLog(WatchFilePathTask. String filePath = ConfigUtils.getInstance().getValue("userfile_path" watchService ="获取监控服务"+="@@@:Path:"+ String todayFormat = DateTime.now().toString("yyyyMMdd"= = existFiles.listFiles( ((todayFormat+".txt" ( !=ImportUserFromFileTask task = (ImportUserFromFileTask) SpringUtils.getApplicationContext().getBean("importUserFromFileTask"WatchKey key = (= (WatchEvent6b3d0130bba23ae47fe2b8e8cddf0195String fileName =((todayFormat+".txt"= path.toFile().getAbsolutePath()+File.separator+"import filePath:"+ImportUserFromFileTask task = (ImportUserFromFileTask) SpringUtils.getApplicationContext().getBean("importUserFromFileTask");"启动线程导入用户数据"+
package com.zealer.ad.task;import com.zealer.ad.entity.AutoPutUser;import com.zealer.ad.entity.Bmsuser;import com.zealer.ad.service.AutoPutUserService;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.joda.time.DateTime;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.InputStreamReader;import java.util.Date;import javax.annotation.Resource;/** * 解析用户文件及入库线程,由WatchFilePathTask启动 * @author cancer * */public class ImportUserFromFileTask extends Thread {private Log log = LogFactory.getLog(ImportUserFromFileTask.class);private String fileName; @Resource(name = "autoPutUserService")private AutoPutUserService autoPutUserService; @Overridepublic void run() { File file = new File(fileName);if (file.exists() && file.isFile()) { log.debug(":@@@准备开始休眠10秒钟:" + file);//休眠十分钟,防止文件过大还没完全拷贝到指定目录下,这里的线程就开始读取文件try { sleep(10000); } catch (InterruptedException e1) { e1.printStackTrace(); } InputStreamReader read;try { read = new InputStreamReader(new FileInputStream(file), "UTF-8"); BufferedReader bufferedReader = new BufferedReader(read); String lineTxt = null;int count = 0; Boolean f = false;while ((lineTxt = bufferedReader.readLine()) != null) {if ((null == lineTxt) || "".equals(lineTxt)) {continue; }if (lineTxt.startsWith("'")) { lineTxt = lineTxt.substring(1, lineTxt.length()); }//解析分隔符为', 'String[] lines = lineTxt.split("', '");int length = lines.length;if (length < 2) {continue; } Bmsuser bmsuser = new Bmsuser(); bmsuser.setName(lines[0]);if (!"".equals(lines[1])) { bmsuser.setCity(lines[1]); } //根据唯一索引已经存在的数据则不插入f = autoPutUserService.insertIgnore(bmsuser);if (f) { count++; } }//汇总数据AutoPutUser autoPutUser = new AutoPutUser(); autoPutUser.setTotalCount(autoPutUserService.getUserCount()); autoPutUser.setCount(count); autoPutUser.setCountDate(new Date(System.currentTimeMillis())); String today = DateTime.now().toString("yyyy-MM-dd"); Integer oldCount = autoPutUserService.getOldCount(today);//如果今天导入过了就更新否则插入if (!oldCount.equals(0)) { autoPutUserService.updateUserData(autoPutUser, today, oldCount); } else { autoPutUserService.gatherUserData(autoPutUser); }//注意:要关闭流 read.close(); } catch (Exception e) { log.error(e.getMessage(), e); } File newFile = new File(file.getPath() +System.currentTimeMillis() + ".complate"); file.renameTo(newFile); } else { log.error(fileName + " file is not exists"); } }public String getFileName() {return fileName; }public void setFileName(String fileName) {this.fileName = fileName; }public AutoPutUserService getAutoPutUserService() {return autoPutUserService; }public void setAutoPutUserService(AutoPutUserService autoPutUserService) {this.autoPutUserService = autoPutUserService; } }
附带:
1、sql脚本
CREATE TABLE `bmsuser` ( `id` int(255) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(32) DEFAULT NULL , `city` varchar(32) DEFAULT NULL COMMENT , PRIMARY KEY (`bmsid`), UNIQUE KEY `bbLoginName` (`bbLoginName`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
2、文件格式,命名为yyyyMMdd.txt
'张三', '深圳'
以上是java利用WatchService实时监控某个目录下的文件变化并按行解析实例详解的详细内容。更多信息请关注PHP中文网其他相关文章!