NIO实现多人聊天
服务器端
/**
* 功能描述: 基于NIO（非线程阻塞）实现的网络聊天室服务端
*
* @since: 1.0.0
* @Author:薛向毅
*/
public class ChatRoomServer {
private Selector selector = null;
static final int port = 8089;
private Charset charset = Charset.forName("UTF-8");
//用来记录在线人数，以及昵称
private static HashSet users = new HashSet();
private static String USER_EXIST = "system message: user exist, please change a name";
//相当于自定义协议格式，与客户端协商好
private static String USER_CONTENT_SPILIT = "：";
private static boolean flag = false;
public void init() throws IOException {
selector = Selector.open();//打开一个通道选择器
//打开一个通道
ServerSocketChannel serverChannel = ServerSocketChannel.open();
//设置为非阻塞的方式
serverChannel.configureBlocking(false);
serverChannel.bind(new InetSocketAddress(port));
//注册到选择器,权限为 接收数据
serverChannel.register(selector, SelectionKey.OP_ACCEPT);
System.out.println("Server is listening now...");
//
while (true) {
int readyChannels = selector.select();//获得所有的通道
if (readyChannels == 0) continue;//如果没有就跳出循环
Set selectionKeys = selector.selectedKeys();//获取可用的通道的集合
//通过迭代器，迭代可用的通道
Iterator keyIterator = selectionKeys.iterator();
while (keyIterator.hasNext()) {
SelectionKey sk = keyIterator.next();
keyIterator.remove();//
//根据选择键，判断channel的方式
dealWithSelectionKey(serverChannel, sk);
}
}
}
public void dealWithSelectionKey(ServerSocketChannel serverChannel, SelectionKey sk) throws IOException {
//如果是接收的通道
if (sk.isAcceptable()) {
SocketChannel sc = serverChannel.accept();
//使用非阻塞模式
sc.configureBlocking(false);
//注册选择器，设置为读取模式，收到一个连接请求，然后起一个SocketChannel，并注册到selector上，之后这个连接的数据，就由这个SocketChannel处理
sc.register(selector, SelectionKey.OP_READ);
//将对应的channel设置为准备接收其他客户端的请求
sk.interestOps(SelectionKey.OP_ACCEPT);
System.out.println("Server is listening from client :" + sc.getRemoteAddress());
sc.write(Charset.forName("UTF-8").encode("请输入你的名字："));
}
//处理来自客户端的数据读取请求
if (sk.isReadable()) {
//返回该selectionKey对应的Channel，其中有数据需要读取
//返回该SelectionKey对应的 Channel，其中有数据需要读取
SocketChannel sc = (SocketChannel) sk.channel();
ByteBuffer buff = ByteBuffer.allocate(1024);
StringBuilder content = new StringBuilder();
try {
while (sc.read(buff) > 0) {
buff.flip();
content.append(charset.decode(buff));
}
System.out.println("Server is listening from client " + sc.getRemoteAddress() + " data rev is: " + content);
//将此对应的channel设置为准备下一次接受数据
sk.interestOps(SelectionKey.OP_READ);
} catch (IOException io) {
sk.cancel();
if (sk.channel() != null) {
sk.channel().close();
}
}
if (content.length() > 0) {
String[] arrayContent = content.toString().split(USER_CONTENT_SPILIT);
//注册用户
if (arrayContent != null && arrayContent.length == 1) {
String name = arrayContent[0];
if (users.contains(name)) {
sc.write(charset.encode(USER_EXIST));
} else {
users.add(name);
int num = OnlineNum(selector);
String message = "welcome " + name + " to chat room! Online numbers:" + num;
BroadCast(selector, null, message);
}
}
//注册完了，发送消息
else if (arrayContent != null && arrayContent.length > 1) {
String name = arrayContent[0];
String message = content.substring(name.length() + USER_CONTENT_SPILIT.length());
message = name + " say " + message;
if (users.contains(name)) {
//不回发给发送此内容的客户端
BroadCast(selector, sc, message);
}
}
}
}
}
//TODO 要是能检测下线，就不用这么统计了
public static int OnlineNum(Selector selector) {
int res = 0;
for (SelectionKey key : selector.keys()) {
Channel targetchannel = key.channel();
if (targetchannel instanceof SocketChannel) {
res++;
}
}
return res;
}
public void BroadCast(Selector selector, SocketChannel except, String content) throws IOException {
//广播数据到所有的SocketChannel中
for (SelectionKey key : selector.keys()) {
Channel targetchannel = key.channel();
//如果except不为空，不回发给发送此内容的客户端
if (targetchannel instanceof SocketChannel && targetchannel != except) {
SocketChannel dest = (SocketChannel) targetchannel;
dest.write(charset.encode(content));
}
}
}
public static void main(String[] args) throws IOException {
new ChatRoomServer().init();
}
} 客户端
/**
* @author 薛向毅
* @create 2018-05-25
10:06
**/
public class ChatRoomClient {
private Selector selector = null;
static final int port = 8089;
private Charset charset = Charset.forName("UTF-8");
private SocketChannel sc = null;
private String name = "";
private static String USER_EXIST = "用户名已经存在，请重新写一个吧";
private static String USER_CONTENT_SPILIT = "：";
public void init() throws IOException {
selector = Selector.open();
//连接远程主机的IP和端口
sc = SocketChannel.open(new InetSocketAddress("127.0.0.1", port));
sc.configureBlocking(false);
sc.register(selector, SelectionKey.OP_READ);
//开辟一个新线程来读取从服务器端的数据s
new Thread(new ClientThread()).start();
//在主线程中 从键盘读取数据输入到服务器端
Scanner scan = new Scanner(System.in);
while (scan.hasNextLine()) {
String line = scan.nextLine();
if ("".equals(line)) continue; //不允许发空消息
if ("".equals(name)) {
name = line;
line = name + USER_CONTENT_SPILIT;
} else {
line = name + USER_CONTENT_SPILIT + line;
}
sc.write(charset.encode(line));//sc既能写也能读，这边是写
}
}
private class ClientThread implements Runnable {
public void run() {
try {
while (true) {
int readyChannels = selector.select();
if (readyChannels == 0) continue;
Set selectedKeys = selector.selectedKeys(); //可以通过这个方法，知道可用通道的集合
Iterator keyIterator = selectedKeys.iterator();
while (keyIterator.hasNext()) {
SelectionKey sk = (SelectionKey) keyIterator.next();
keyIterator.remove();
dealWithSelectionKey(sk);
}
}
} catch (IOException io) {
}
}
private void dealWithSelectionKey(SelectionKey sk) throws IOException {
if (sk.isReadable()) {
//使用 NIO 读取 Channel中的数据，这个和全局变量sc是一样的，因为只注册了一个SocketChannel
//sc既能写也能读，这边是读
SocketChannel sc = (SocketChannel) sk.channel();
ByteBuffer buff = ByteBuffer.allocate(1024);
String content = "";
while (sc.read(buff) > 0) {
buff.flip();
content += charset.decode(buff);
}
//若系统发送通知名字已经存在，则需要换个昵称
if (USER_EXIST.equals(content)) {
name = "";
}
System.out.println(content);
sk.interestOps(SelectionKey.OP_READ);
}
}
}
public static void main(String[] args) throws IOException {
new ChatRoomClient().init();
}
}