客户端未连接到服务器

Question

我有一些在java中使用nio的服务器和客户端代码。当我尝试连接到服务器时，sctpChannel.connect(new InetSocketAddress("127.0.0.1",4545));返回false。并且CCD_ 2返回0。我不明白为什么会发生这种事。

public class SctpNioServer {
public static void main(String[] args)throws  Exception{
InetSocketAddress inetSocketAddress = new InetSocketAddress("localhost",4545);
SctpServerChannel serverChannel = SctpServerChannel.open();
serverChannel.bind(inetSocketAddress);
serverChannel.configureBlocking(false);
Selector selector = Selector.open();
serverChannel.register(selector,SelectionKey.OP_ACCEPT );
while(true){
try{
selector.select();
Set<SelectionKey> selectedKeys = selector.selectedKeys() ;
Iterator<SelectionKey> iterator = selectedKeys.iterator();
while (iterator.hasNext()){
SelectionKey key = iterator.next();
iterator.remove();
if(key.isAcceptable()){
SctpChannel channel = serverChannel.accept();
channel.configureBlocking(false) ;
channel.register(selector,SelectionKey.OP_READ);
}
if (key.isReadable()){
SctpChannel channel = (SctpChannel) key.channel();
ByteBuffer byteBuffer = ByteBuffer.allocate(4096);
channel.receive(byteBuffer,null,null);
byteBuffer.flip();
while (byteBuffer.hasRemaining()){
System.out.println((char)byteBuffer.get());
}
byteBuffer.clear();
channel.register(selector, SelectionKey.OP_WRITE);
}
if(key.isWritable()){
//doSomething
}
}
selector.wakeup();
}
catch (IOException e){
e.printStackTrace();
}
finally {
serverChannel.close();
}
}
}}
public class SctpNioClient  {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
try {
SctpChannel channel = SctpChannel.open();
channel.configureBlocking(false);
channel.connect(new InetSocketAddress("localhost", 4545));
Selector sel = Selector.open();
channel.register(sel, SelectionKey.OP_CONNECT);
while (true) {
if (sel.isOpen()) {
int keys = sel.select(5);
if (keys > 0) {
Set<SelectionKey> selectedKeys = sel.selectedKeys();
for (SelectionKey sk : selectedKeys) {
if (!sk.isValid()) {
break;
}
if (sk.isConnectable()) {
channel.finishConnect();
channel.register(sel, SelectionKey.OP_WRITE, channel);
}
if (sk.isWritable()) {
SctpChannel ch = (SctpChannel) sk.channel();
System.out.println("writing->");
ByteBuffer byteBuffer = ByteBuffer.allocate(4096);
String text = scanner.nextLine();
byteBuffer.clear();
byteBuffer.put(text.getBytes());
byteBuffer.flip();
MessageInfo messageInfo = MessageInfo.createOutgoing(null,null,0);
ch.send(byteBuffer,messageInfo);
ch.register(sel , SelectionKey.OP_READ);
sel.wakeup();
}
if(sk.isReadable()){
SctpChannel ch = (SctpChannel) sk.channel();
ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
ch.receive(byteBuffer,null,null);
byteBuffer.flip();
while (byteBuffer.hasRemaining()){
System.out.println((char)byteBuffer.get());
}
ch.register(sel,SelectionKey.OP_WRITE);
} } } } }
} catch (IOException ex) { }
}}

Answer 1

1. connect()返回布尔值。您声称它是假的，但您的代码忽略了它
2. 如果它返回true，则不需要注册OP_CONNECT：但由于忽略了它，因此也忽略了这个事实
3. finishConnect()也返回一个布尔值，您也将忽略该布尔值
4. 所有这些操作都可以抛出IOExceptions，您也忽略了它

解决方案：不要。在所有情况下。