import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.nio.ByteBuffer; import java.nio.channels.FileChannel; import java.nio.channels.FileLock; public class FileLockDemo { /** * Filelock 防止程序在运行期间,线程在访问文件的过程中修改文件导致Buffer中 * 的部分或者全部内容不可读,造成程序异常。 * 例子中展示的是新开以个线程访问主线程Filelock的文件。 * @throws IOException */ public static void main(String[] args) throws IOException { File file = new File("D://in.txt"); FileOutputStream fis = new FileOutputStream(file); FileChannel fc = fis.getChannel(); FileLock flock = fc.tryLock(); if(flock.isValid()){ System.out.println(file.getName()+ "is locked"); } new Thread(){ public void run(){ try{ File file = new File("D://in.txt"); FileOutputStream fi = new FileOutputStream(file); fi.write('b'); }catch(Exception e){ e.printStackTrace(); } } }.run(); flock.release(); System.out.println(file.getName()+ "is released"); fc.close(); fis.close(); } }
?结果是该文件无法被新起的线程访问,运行结果:
in.txtis locked
java.io.IOException: The process cannot access the file because another process has locked a portion of the file
at java.io.FileOutputStream.write(Native Method)
at com.cn.tibco.nio.FileLockDemo$1.run(FileLockDemo.java:32)
at com.cn.tibco.nio.FileLockDemo.main(FileLockDemo.java:37)
in.txtis released