private void recv(SocketChannel sc, ClientInfo ci) throws IOException {
ci.channel.read(ci.inBuf);
ByteBuffer tmpBuf = ci.inBuf.duplicate();
tmpBuf.flip();
int bytesProcessed = 0;
boolean doneLoop = false;
while (!doneLoop) {
byte b;
try {
b = tmpBuf.get();
} catch (BufferUnderflowException bue) {
// Processed all data in buffer
ci.inBuf.clear();
doneLoop = true;
break;
}
switch (b) {
case TypeServerConstants.WELCOME:
bytesProcessed++;
break;
case TypeServerConstants.GET_STRING_REQUEST:
bytesProcessed++;
if (ci.outputPending) {
// Client is backed up. We can't append to
// the byte buffer because it's in the wrong
// state. We could allocate another buffer
// here and change our send method to know
// about multiple buffers, but we'll just
// assume that the client is dead
break;
}
ci.outBuf.put(TypeServerConstants.GET_STRING_RESPONSE);
ByteBuffer strBuf = encoder.encode(testString);
ci.outBuf.putShort((short) strBuf.remaining());
ci.outBuf.put(strBuf);
ci.outBuf.flip();
send(sc, ci);
break;
case TypeServerConstants.GET_STRING_RESPONSE:
int startPos = tmpBuf.position();
try {
int nBytes = tmpBuf.getInt();
byte[] buf = new byte[nBytes];
tmpBuf.get(buf);
bytesProcessed += buf.length + 5;
String s = new String(buf);
// Send the string to the GUI
break;
} catch (BufferUnderflowException bue) {
// Processed all available data
ci.inBuf.position(ci.inBuf.position() + bytesProcessed);
doneLoop = true;
}
break;
}
}
}
// 感觉如果没有看过 NIO 的详细内容是不会懂这部分
public class TypeServer extends TCPNIOServer {
static String testString = "Thisisateststring";
static class ClientInfo {
ByteBuffer inBuf = ByteBuffer.allocateDirect(512);
ByteBuffer outBuf = ByteBuffer.allocateDirect(512);
boolean outputPending = false;
SocketChannel channel;
}
Map allClients = new HashMap();
Charset encoder = Charset.forName("UTF-8");
protected void handleClient(SelectionKey key) throws IOException {
SocketChannel sc = (SocketChannel) key.channel();
ClientInfo ci = (ClientInfo) allClients.get(sc);
if (ci == null) throw new IllegalStateException("Unknown client");
if (key.isWritable()) send(sc, ci);
if (key.isReadable())
// 从一个客户端读进所有的可用数据
recv(sc, ci);
}
private void recv(SocketChannel sc, ClientInfo ci) throws IOException {
ci.channel.read(ci.inBuf);
ByteBuffer tmpBuf = ci.inBuf.duplicate();
tmpBuf.flip();
int bytesProcessed = 0;
boolean doneLoop = false;
while (!doneLoop) {
byte b;
try {
b = tmpBuf.get();
} catch (BufferUnderflowException bue) {
// Processed all data in buffer
ci.inBuf.clear();
doneLoop = true;
break;
}
switch (b) {
case TypeServerConstants.WELCOME:
bytesProcessed++;
break;
case TypeServerConstants.GET_STRING_REQUEST:
bytesProcessed++;
if (ci.outputPending) {
// Client is backed up. We can't append to
// the byte buffer because it's in the wrong
// state. We could allocate another buffer
// here and change our send method to know
// about multiple buffers, but we'll just
// assume that the client is dead
break;
}
ci.outBuf.put(TypeServerConstants.GET_STRING_RESPONSE);
ByteBuffer strBuf = encoder.encode(testString);
ci.outBuf.putShort((short) strBuf.remaining());
ci.outBuf.put(strBuf);
ci.outBuf.flip();
send(sc, ci);
break;
case TypeServerConstants.GET_STRING_RESPONSE:
int startPos = tmpBuf.position();
try {
int nBytes = tmpBuf.getInt();
byte[] buf = new byte[nBytes];
tmpBuf.get(buf);
bytesProcessed += buf.length + 5;
String s = new String(buf);
// Send the string to the GUI
break;
} catch (BufferUnderflowException bue) {
// Processed all available data
ci.inBuf.position(ci.inBuf.position() + bytesProcessed);
doneLoop = true;
}
break;
}
}
}
private void send(SocketChannel sc, ClientInfo ci) throws IOException {
int len = ci.outBuf.remaining();
int nBytes = sc.write(ci.outBuf);
if (nBytes != len) {
// Client not ready to receive data
ci.outputPending = true;
ci.channel.register(selector, SelectionKey.OP_READ | SelectionKey.OP_WRITE);
} else {
ci.outBuf.clear();
if (ci.outputPending) {
ci.outputPending = false;
ci.channel.register(selector, SelectionKey.OP_READ);
}
}
}
protected void registeredClient(SocketChannel sc) throws IOException {
ClientInfo ci = new ClientInfo();
ci.channel = sc;
ci.outBuf.clear();
ci.outBuf.put(TypeServerConstants.WELCOME);
ci.outBuf.flip();
allClients.put(sc, ci);
send(sc, ci);
}
public static void main(String[] args) throws Exception {
TypeServer ts = new TypeServer();
ts.port = Integer.parseInt(args[0]);
Thread t = new Thread(ts);
t.start();
System.out.println("Type server ready...Type CTRL-D to exit");
while (System.in.read() > 0) ;
ts.stopServer();
t.join();
}
}