FileLock

import org.junit.Ignore;import org.junit.Test;import java.io.File;import java.io.RandomAccessFile;import java.nio.channels.FileLock;public class FileLockTest {       @Test    public void testFileLock2() throws            Exception {        File file = new File("/tmp/stamp.txt");        RandomAccessFile out = new RandomAccessFile(file, "rw");        if (!file.exists())            file.createNewFile();        FileLock fileLock = out.getChannel().tryLock();        if (null != fileLock) {            out.writeUTF(NLPConstants.DEFAULT_TIME_FORMATTER.print(System.currentTimeMillis()));            fileLock.release();            out.close();        } else {            System.err.println("this file has been open but other person!");        }        //////in        RandomAccessFile in = new RandomAccessFile(file, "rw");        if (!file.exists())            System.err.println("not exists");        FileLock fileLockIn = in.getChannel().tryLock();        if (null != fileLockIn) {            String ret = in.readUTF();            System.out.println(ret);            fileLockIn.release();            in.close();        } else {            System.err.println("this file has been open but other person!");        }    }}