我有一个Server类和一个Timer，它应该清除死掉的客户端(崩溃的客户端)。我遵循下面的示例，在Timer遍历用户时锁定了集合，但仍然收到此异常(在使连接的客户端崩溃之后)。
http://www.javaperformancetuning.com/articles/fastfail2.shtml
List<User> users;
List<User> connectedUsers;
ConcurrentMap<User, IClient> clients;
...
users = Collections.synchronizedList(new ArrayList<User>());
connectedUsers = new ArrayList<User>();
clients = new ConcurrentHashMap<User, IClient>();
timer = new Timer();
timer.schedule(new ClearDeadClients(), 5000, 5000);
...
class ClearDeadClients extends TimerTask {
public void run() {
synchronized (users) {
Iterator<User> it = users.iterator();
while (it.hasNext()) {
User user = it.next(); // Throws exception
if (!connectedUsers.contains(user)) {
users.remove(user);
clients.remove(user);
}
}
}
connectedUsers.clear();
}
}
最佳答案
您需要从迭代器中删除而不是从集合中删除。它看起来像这样:
Iterator<User> it = users.iterator();
while (it.hasNext()) {
User user = it.next();
if (!connectedUsers.contains(user)) {
it.remove();
clients.remove(user);
}
}