1、创建服务端代码
public class NioServer {
private static Map<String, SocketChannel> clientMap = new HashMap<>();
public static void main(String[] args) throws IOException {
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.configureBlocking(false);
ServerSocket serverSocket = serverSocketChannel.socket();
serverSocket.bind(new InetSocketAddress(8899));
Selector selector = Selector.open();
serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
while (true){
try {
selector.select();
Set<SelectionKey> selectionKeys = selector.selectedKeys();
selectionKeys.forEach( selectionKey -> {
final SocketChannel client;
try{
//客户端向服务端发起一个连接
if(selectionKey.isAcceptable()){
ServerSocketChannel server = (ServerSocketChannel)selectionKey.channel();
client = server.accept();
client.configureBlocking(false);
client.register(selector, SelectionKey.OP_READ);
String key = "[" + UUID.randomUUID() + "]";
clientMap.put(key, client);
}
//有数据可读
else if(selectionKey.isReadable()){
client = (SocketChannel)selectionKey.channel();
ByteBuffer readBuffer = ByteBuffer.allocate(1024);
int count = client.read(readBuffer);
if(count > 0){
readBuffer.flip();
Charset charset = Charset.forName("utf-8");
String receivedMessage = String.valueOf(charset.decode(readBuffer).array());
System.out.println(client + ": " + receivedMessage);
String senderKey = null;
for(Map.Entry<String,SocketChannel> entry : clientMap.entrySet()){
if(client == entry.getValue()){
senderKey = entry.getKey();
break;
}
}
for(Map.Entry<String,SocketChannel> entry : clientMap.entrySet()){
SocketChannel value = entry.getValue();
ByteBuffer writeBuffer = ByteBuffer.allocate(1024);
writeBuffer.put((senderKey + ":" + receivedMessage).getBytes());
writeBuffer.flip();
value.write(writeBuffer);
}
}
}
}catch (Exception ex){
ex.printStackTrace();
}
});
selectionKeys.clear();
}catch (Exception ex){
ex.printStackTrace();
}
}
}
}
2、创建客户端代码
public class NioClient {
public static void main(String[] args) {
try{
SocketChannel socketChannel = SocketChannel.open();
socketChannel.configureBlocking(false);
Selector selector = Selector.open();
socketChannel.register(selector, SelectionKey.OP_CONNECT);
socketChannel.connect(new InetSocketAddress("127.0.0.1",8899));
while (true){
selector.select();
Set<SelectionKey> keySet = selector.selectedKeys();
for(SelectionKey selectionKey : keySet){
//与服务端已经建立好了连接
if(selectionKey.isConnectable()){
SocketChannel client = (SocketChannel)selectionKey.channel();
if(client.isConnectionPending()){
client.finishConnect();
//向服务端发数据
ByteBuffer writeBuffer = ByteBuffer.allocate(1024);
writeBuffer.put((LocalDateTime.now() + "连接成功").getBytes());
writeBuffer.flip();
client.write(writeBuffer);
// 启动一个线程，不断的读取标准输入的内容。然后将内容向回个服务端
ExecutorService executorService = Executors.newSingleThreadExecutor(Executors.defaultThreadFactory());
executorService.submit(() -> {
while (true){
try {
writeBuffer.clear();
InputStreamReader input = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(input);
String sendMessage = br.readLine();
writeBuffer.put(sendMessage.getBytes());
writeBuffer.flip();
client.write(writeBuffer);
}catch (Exception ex){
ex.printStackTrace();
}
}
});
}
client.register(selector, SelectionKey.OP_READ);
}else if(selectionKey.isReadable()){
SocketChannel client = (SocketChannel)selectionKey.channel();
ByteBuffer readBuffer = ByteBuffer.allocate(1024);
int count = client.read(readBuffer);
if(count > 0){
String receivedMessage = new String(readBuffer.array(), 0, count);
System.out.println(receivedMessage);
}
}
}
keySet.clear();
}
}catch (Exception ex){
ex.printStackTrace();
}
}
}
3、测试
1) 启动服务端
2) 启动两个客户端
3) 输出结果
NioServer输出
第一个NioClient输出。连接建立后，输入hello
第二个NioClient输出。 连接建立后，输入world
