NIO读写文件并加锁

一、读取文件

 package lock;

 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.RandomAccessFile;
 import java.nio.channels.FileChannel;
 import java.nio.channels.FileLock;
 import java.util.Calendar;

 public class ReadFileLock implements Runnable {

     public void run() {
         try {
             Calendar calstart = Calendar.getInstance();
             Thread.sleep(5000);
             File file = new File("D:/test.txt");
             // 给该文件加锁
             RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");
             FileChannel fileChannel = randomAccessFile.getChannel();
             FileLock fileLock = null;
             while (true) {
                 try {
                     fileLock = fileChannel.tryLock();
                     break;
                 } catch (Exception e) {
                     System.out.println("有其他线程正在操作该文件，当前线程" + Thread.currentThread().getName() + "休眠1000毫秒");
                     Thread.sleep(1000);
                 }
             }
             byte[] buf = new byte[1024];
             StringBuffer sb = new StringBuffer();
             while ((randomAccessFile.read(buf)) != -1) {
                 sb.append(new String(buf, "utf-8"));
                 buf = new byte[850];
             }

             System.err.println(sb.toString());

             fileLock.release();
             fileChannel.close();
             randomAccessFile.close();
             randomAccessFile = null;

             Calendar calend = Calendar.getInstance();
             System.out.println("当前线程:" + Thread.currentThread().getName() + ",读文件共花了"
                     + (calend.getTimeInMillis() - calstart.getTimeInMillis()) + "秒");
         } catch (FileNotFoundException e) {
             e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
         } catch (InterruptedException e) {
             e.printStackTrace();
         }
     }

     public static void main(String[] args) {
         ReadFileLock  threadTarget = new ReadFileLock();
         Thread read = new Thread(threadTarget);
         read.setName("thread-read-file");
         read.start();
         Thread read2 = new Thread(threadTarget);
         read2.setName("thread-write-file2");
         read2.start();
     }

 }

二、写文件

package lock;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
import java.util.Calendar;

public class ReadFileLock implements Runnable {

	public void run() {
		try {
			Calendar calstart = Calendar.getInstance();
			Thread.sleep(5000);
			File file = new File("D:/test.txt");
			// 给该文件加锁
			RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");
			FileChannel fileChannel = randomAccessFile.getChannel();
			FileLock fileLock = null;
			while (true) {
				try {
					fileLock = fileChannel.tryLock();
					break;
				} catch (Exception e) {
					System.out.println("有其他线程正在操作该文件，当前线程" + Thread.currentThread().getName() + "休眠1000毫秒");
					Thread.sleep(1000);
				}
			}
			byte[] buf = new byte[1024];
			StringBuffer sb = new StringBuffer();
			while ((randomAccessFile.read(buf)) != -1) {
				sb.append(new String(buf, "utf-8"));
				buf = new byte[850];
			}

			System.err.println(sb.toString());

			fileLock.release();
			fileChannel.close();
			randomAccessFile.close();
			randomAccessFile = null;

			Calendar calend = Calendar.getInstance();
			System.out.println("当前线程:" + Thread.currentThread().getName() + ",读文件共花了"
					+ (calend.getTimeInMillis() - calstart.getTimeInMillis()) + "秒");
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}

	public static void main(String[] args) {
		ReadFileLock  threadTarget = new ReadFileLock();
		Thread read = new Thread(threadTarget);
		read.setName("thread-read-file");
		read.start();
		Thread read2 = new Thread(threadTarget);
		read2.setName("thread-write-file2");
		read2.start();
	}

}