考虑TIJ第4版中的此代码
class SleepBlocked implements Runnable {
public void run() {
try {
TimeUnit.SECONDS.sleep(100);
} catch(InterruptedException e) {
print("InterruptedException");
}
print("Exiting SleepBlocked.run()");
}
}
class IOBlocked implements Runnable {
private InputStream in;
public IOBlocked(InputStream is) { in = is; }
public void run() {
try {
print("Waiting for read():");
in.read();
} catch(IOException e) {
if(Thread.currentThread().isInterrupted()) {
print("Interrupted from blocked I/O");
} else {
throw new RuntimeException(e);
}
}
print("Exiting IOBlocked.run()");
}
}
class SynchronizedBlocked implements Runnable {
public synchronized void f() {
while(true) // Never releases lock
Thread.yield();
}
public SynchronizedBlocked() {
new Thread() {
public void run() {
f(); // Lock acquired by this thread
}
}.start();
}
public void run() {
print("Trying to call f()");
f();
print("Exiting SynchronizedBlocked.run()");
}
}
public class Interrupting {
private static ExecutorService exec =
Executors.newCachedThreadPool();
static void test(Runnable r) throws InterruptedException{
Future<?> f = exec.submit(r);
TimeUnit.MILLISECONDS.sleep(100);
print("Interrupting " + r.getClass().getName());
f.cancel(true); // Interrupts if running
print("Interrupt sent to " + r.getClass().getName());
}
public static void main(String[] args) throws Exception {
test(new SleepBlocked());
test(new IOBlocked(System.in));
test(new SynchronizedBlocked());
TimeUnit.SECONDS.sleep(3);
print("Aborting with System.exit(0)");
System.exit(0);
}
}
这是输出
Interrupting SleepBlocked
InterruptedException
Exiting SleepBlocked.run()
Interrupt sent to SleepBlocked
Waiting for read():
Interrupting IOBlocked
Interrupt sent to IOBlocked
Trying to call f()
Interrupting SynchronizedBlocked
Interrupt sent to SynchronizedBlocked
Aborting with System.exit(0)
在这里,您可以看到所有创建的线程最后都被中断了(这是我的想法,因为没有人执行它的run方法直到最后),但是在那之后,Bruce Eckel继续说
您无法中断正在尝试获取同步的任务
锁或试图执行I / O的锁。
还是在这里中断意味着其他东西?
他还说
SleepBlock是可中断阻止的示例,而IOBlocked
和SynchronizedBlocked是不间断的阻塞。
他在这里不间断地封锁是什么意思?谁能指定两者之间的区别?
最佳答案
他已经过时,或者您的版本已经过时。 NIO通过InterruptibleChannel
支持可中断的I / O,尽管由于可笑的Linux中断语义,仅以相当无用的方式关闭了通道。java.io
和java.net
I / O操作不受中断的影响,您的问题中没有什么可以证明是相反的。如果是的话,您将在输出中看到"Interrupted from blocked I/O"
,而您没有看到。您的I / O线程仍在in.read()
中被阻止。