一、读取文件
1 package lock; 2 3 import java.io.File; 4 import java.io.FileNotFoundException; 5 import java.io.IOException; 6 import java.io.RandomAccessFile; 7 import java.nio.channels.FileChannel; 8 import java.nio.channels.FileLock; 9 import java.util.Calendar; 10 11 public class ReadFileLock implements Runnable { 12 13 public void run() { 14 try { 15 Calendar calstart = Calendar.getInstance(); 16 Thread.sleep(5000); 17 File file = new File("D:/test.txt"); 18 // 给该文件加锁 19 RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw"); 20 FileChannel fileChannel = randomAccessFile.getChannel(); 21 FileLock fileLock = null; 22 while (true) { 23 try { 24 fileLock = fileChannel.tryLock(); 25 break; 26 } catch (Exception e) { 27 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"); 28 Thread.sleep(1000); 29 } 30 } 31 byte[] buf = new byte[1024]; 32 StringBuffer sb = new StringBuffer(); 33 while ((randomAccessFile.read(buf)) != -1) { 34 sb.append(new String(buf, "utf-8")); 35 buf = new byte[850]; 36 } 37 38 System.err.println(sb.toString()); 39 40 fileLock.release(); 41 fileChannel.close(); 42 randomAccessFile.close(); 43 randomAccessFile = null; 44 45 Calendar calend = Calendar.getInstance(); 46 System.out.println("当前线程:" + Thread.currentThread().getName() + ",读文件共花了" 47 + (calend.getTimeInMillis() - calstart.getTimeInMillis()) + "秒"); 48 } catch (FileNotFoundException e) { 49 e.printStackTrace(); 50 } catch (IOException e) { 51 e.printStackTrace(); 52 } catch (InterruptedException e) { 53 e.printStackTrace(); 54 } 55 } 56 57 public static void main(String[] args) { 58 ReadFileLock threadTarget = new ReadFileLock(); 59 Thread read = new Thread(threadTarget); 60 read.setName("thread-read-file"); 61 read.start(); 62 Thread read2 = new Thread(threadTarget); 63 read2.setName("thread-write-file2"); 64 read2.start(); 65 } 66 67 }
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();
}
}