java实时读取和写入文件（线程实现）

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package org.log.file; import java.io.*;import java.text.SimpleDateFormat;import java.util.Date;import java.util.concurrent.Executors;import java.util.concurrent.ScheduledExecutorService;import java.util.concurrent.TimeUnit; /** * 实时写入和读取指定文件的内容 * Created by lgq on 2015/6/3. */public class LogView {     private long lastTimeFileSize = 0;     /**     * 实时读取指定文件的内容     * @param logFile     * @throws FileNotFoundException     */    public void realtimeShowLog(File logFile) throws FileNotFoundException {        //指定文件可读可写        final RandomAccessFile randomAccessFile = 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() {            @Override            public void run() {                try {                    //获得变化部分的                    randomAccessFile.seek(lastTimeFileSize);                    String tmp = "";                    while ( (tmp = randomAccessFile.readLine()) != null) {                        // 输出文件内容                        System.out.println(new String(tmp.getBytes("ISO8859-1")));                        lastTimeFileSize = randomAccessFile.length();                    }                } catch (IOException e) {                    e.printStackTrace();                }            }        }, 0, 10, TimeUnit.SECONDS);     }      private SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");    String msgInfo = "this is a message, 这是一条信息。this is a message, 这是一条信息。";     /**     * 实时写入日志到指定文件     * @throws IOException     */    public void writerLog() throws IOException {        final File logFile = new File("E:\\Program Files\\tomcat6\\logs\\mock.log");        if(!logFile.exists()) {            logFile.createNewFile();        }        //启动一个线程每2秒钟向日志文件写一次数据        ScheduledExecutorService exec =  Executors.newScheduledThreadPool(1);        exec.scheduleWithFixedDelay(new Runnable(){            public void run() {                try {                    if(logFile == null) {                        throw new IllegalStateException("logFile can not be null!");                    }                    Writer txtWriter = new FileWriter(logFile,true);                    txtWriter.write(dateFormat.format(new Date()) +"\t"+ msgInfo +"\n");                    txtWriter.flush();                } catch (IOException e) {                    throw new RuntimeException(e);                }            }        }, 0, 2, TimeUnit.SECONDS);    }      public static void main(String[] args) throws Exception {        LogView view = new LogView();        view.writerLog();        final File tmpLogFile = new File("E:\\Program Files\\tomcat6\\logs\\mock.log");        view.realtimeShowLog(tmpLogFile);    } }
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