文件是否增加了新的内容

public class TestLogOut {
public static void main(String[] args) {
//要读的TXT文件
final File tmpLogFile = new File("LogShow.txt");
try {
realtimeShowLog(tmpLogFile);

} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

private long lastTimeFileSize = 0;  //上次文件大小
/**
* 实时输出日志信息
* @param logFile 日志文件
* @throws IOException
*/
public void realtimeShowLog(File logFile) throws IOException{
//指定文件可读可写
final RandomAccessFile randomFile = new RandomAccessFile(logFile,"rw");
//启动一个线程每10秒钟读取新增的日志信息
ScheduledExecutorService exec =
Executors.newScheduledThreadPool(1);
exec.scheduleWithFixedDelay(new Runnable(){
public void run() {
try {
//获得变化部分的
randomFile.seek(lastTimeFileSize);
String tmp = "";
while( (tmp = randomFile.readLine())!= null) {
System.out.println("log正常输出中");
}
System.out.println("log输出结束");
lastTimeFileSize = randomFile.length();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}, 0, 10, TimeUnit.SECONDS);
}
}