读取更新的日志

public class ReadLog {
    //设置变量 记录上次读取位置
    private long num = 0;

    public void readAW() throws IOException {
        File file = new File("/Users/shunzhang/Downloads/fio-test-zs.log");
        RandomAccessFile randomAccessFile = new RandomAccessFile(file,"rw");
        //将文件定位到偏移量所指位置，在该位置发生下一个读取或写入操作
        randomAccessFile.seek(num);
        //获取按行读取的数据并落库
        String s = randomAccessFile.readLine();
        for(;s!= null;s = randomAccessFile.readLine()){
            System.out.println("打印："+s);
        }
        //重新计算偏移量，做下一次读取时的初始偏移量
        num= randomAccessFile.length();
    }
}

 

 

public class LogView {

    public static boolean firstRead = true;
    public static int countdown = 0;
    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1秒钟读取新增的日志信息

        ScheduledExecutorService exec = Executors.newScheduledThreadPool(1);

        exec.scheduleWithFixedDelay(new Runnable() {

            public void run() {

                try {
                 //将文件记录指针定位到pos位置，一开始从0的位置开始读取

                    randomFile.seek(lastTimeFileSize);

                    String tmp = "";

                    while ((tmp = randomFile.readLine()) != null) {

                        String s = new String(tmp.getBytes("ISO8859-1"));

                        String[] split = s.trim().split("\\s+");

                        String s1 = Arrays.toString(split);
                        lastTimeFileSize = randomFile.length();

                        //去除空集合
                        if(firstRead){
                            System.out.println("11111: "+s1);
                            continue;
                        }
                        if(!s1.equals("[]")){
                            System.out.println("gggg: "+s1);
                        }
                    }
                } catch (IOException e) {

                    throw new RuntimeException(e);

                }

            }

        }, 0, 1, TimeUnit.SECONDS);

    }

    public static void main(String[] args) throws Exception {

        LogView view = new LogView();

       // final File tmpLogFile = new File("/Users/shunzhang/Downloads/fio-test-zs.log");
         final File tmpLogFile = new File("mock.log");

        view.realtimeShowLog(tmpLogFile);

        countdown = 10000;
        Thread.sleep(countdown);
        firstRead = false;
    }

}