NIO[SelectableChannel.register和Selector.select会有锁等待冲突]
结论： register得放在select之前进行
Thread Dump信息：
"Poller-1" prio=6 tid=0x040f0400 nid=0x408 runnable [0x044df000]
java.lang.Thread.State: RUNNABLE
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll0(Native Method)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll(WindowsSelectorImpl.j
ava:295)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.access$400(WindowsSelector
Impl.java:277)
at sun.nio.ch.WindowsSelectorImpl.doSelect(WindowsSelectorImpl.java:158)
at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:87)
- locked <0x23b7df70> (a sun.nio.ch.Util$2)
- locked <0x23b7df60> (a java.util.Collections$UnmodifiableSet)
- locked <0x23b7dd40> (a sun.nio.ch.WindowsSelectorImpl)
at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:98)
at com.zhh.nio.NioServer$Poller.run(NioServer.java:132)
at java.lang.Thread.run(Thread.java:722)
"Poller-0" prio=6 tid=0x040f0000 nid=0x14e4 runnable [0x0439f000]
java.lang.Thread.State: RUNNABLE
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll0(Native Method)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll(WindowsSelectorImpl.j
ava:295)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.access$400(WindowsSelector
Impl.java:277)
at sun.nio.ch.WindowsSelectorImpl.doSelect(WindowsSelectorImpl.java:158)
at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:87)
- locked <0x23b77a98> (a sun.nio.ch.Util$2)
- locked <0x23b77a20> (a java.util.Collections$UnmodifiableSet)
- locked <0x23b76aa0> (a sun.nio.ch.WindowsSelectorImpl)
at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:98)
at com.zhh.nio.NioServer$Poller.run(NioServer.java:132)
at java.lang.Thread.run(Thread.java:722)
"Acceptor" prio=6 tid=0x040ef800 nid=0x1250 waiting for monitor entry [0x03f1f00
0]
java.lang.Thread.State: BLOCKED (on object monitor)
at sun.nio.ch.SelectorImpl.register(SelectorImpl.java:133)
-
waiting to lock <0x23b7df60> (a java.util.Collections$UnmodifiableSet)
at java.nio.channels.spi.AbstractSelectableChannel.register(AbstractSele
ctableChannel.java:207)
- locked <0x23b8da18> (a java.lang.Object)
at java.nio.channels.SelectableChannel.register(SelectableChannel.java:2
77)
at com.zhh.nio.NioSession.register(NioSession.java:50)
at com.zhh.nio.NioServer$Poller.register(NioServer.java:123)
at com.zhh.nio.NioServer.handleNewSession(NioServer.java:222)
at com.zhh.nio.NioServer$Acceptor.run(NioServer.java:236)
at java.lang.Thread.run(Thread.java:722)
Code层面：
select：
private int lockAndDoSelect(long timeout) throws IOException {
synchronized (this) {
if (!isOpen())
throw new ClosedSelectorException();
synchronized (publicKeys) {
synchronized (publicSelectedKeys) {
return doSelect(timeout);
}
}
}
}
register：
protected final SelectionKey register(AbstractSelectableChannel ch,
int ops,
Object attachment)
{
if (!(ch instanceof SelChImpl))
throw new IllegalSelectorException();
SelectionKeyImpl k = new SelectionKeyImpl((SelChImpl)ch, this);
k.attach(attachment);
synchronized (publicKeys) {
implRegister(k);
}
k.interestOps(ops);
return k;
}