1. 服务端
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.util.Iterator;
import java.util.Set;
public class GroupChatServer {
private Selector selector;
private ServerSocketChannel listenChannel;
private static final int PORT = 8888;
// 构造 器
public GroupChatServer() {
try {
selector = Selector.open();
listenChannel = ServerSocketChannel.open();
// 绑定端口
listenChannel.socket().bind(new InetSocketAddress(PORT));
// 设置非阻塞模式
listenChannel.configureBlocking(false);
// 将listenChannel注册到selector
listenChannel.register(selector, SelectionKey.OP_ACCEPT);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 监听
*/
public void listen() {
try {
while (true) {
//select(2000) 只阻塞2秒
// int count = selector.select(2000);
// select()方法一直阻塞
int count = selector.select();
if (count > 0) {
// 遍历得到所有的SelectionKey集合
Iterator<SelectionKey> keysIterator = selector.selectedKeys().iterator();
while (keysIterator.hasNext()) {
// 处理每个selectionKey
SelectionKey selectionKey = keysIterator.next();
// 监听到连接事件
if (selectionKey.isAcceptable()) {
SocketChannel socketChannel = listenChannel.accept();
socketChannel.configureBlocking(false);
//注册
socketChannel.register(selector, SelectionKey.OP_READ);
// 提示上线
System.out.println(socketChannel.getRemoteAddress() + "上线");
}
// 通道可读事件
if (selectionKey.isReadable()) {
// todo 处理读
readMessage(selectionKey);
}
// 删除key,防止重复处理
keysIterator.remove();
}
} else {
// System.out.println("等待中。。。。");
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 读取客户端消息
*
* @param key
*/
public void readMessage(SelectionKey key) {
SocketChannel socketChannel = null;
try {
socketChannel = (SocketChannel) key.channel();
ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
int read = socketChannel.read(byteBuffer);
// 根据read值做处理，如果read > 0 说明真的读取到数据了
if (read > 0) {
String message = new String(byteBuffer.array());
System.out.println("Form Client : " + message);
// todo 向其它客户端 转发消息
sendInfoToOtherClient(message, socketChannel);
}
} catch (IOException e) {
try {
System.out.println(socketChannel.getRemoteAddress() + "离线了。。。");
// 离线之后取消注册
key.cancel();
// 关闭channel
socketChannel.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
/**
* 转发消息到其它客户端
*
* @param message 转发的消息
* @param self ： 排除的channel
*/
public void sendInfoToOtherClient(String message, SocketChannel self) throws IOException {
System.out.println("服务器转发消息中。。。");
// 遍历所有注册到selector上的socketChannel,并排除自己
Set<SelectionKey> keys = selector.keys();
for (SelectionKey key : keys) {
// 通过key取出对应的SocketChannel
Channel targetChannel = key.channel();
// 排除自己
if (targetChannel instanceof SocketChannel && targetChannel != self) {
SocketChannel target = (SocketChannel) targetChannel;
// 将message 存储到buffer
ByteBuffer buffer = ByteBuffer.wrap(message.getBytes());
// 将buffer中的数据写入通道
target.write(buffer);
}
}
}
public static void main(String[] args) {
//创建对象
GroupChatServer chatServer = new GroupChatServer();
chatServer.listen();
}
}
2. 客户端
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Scanner;
import java.util.Set;
public class GroupChatClient {
// 服务器ip
private final String HOST = "127.0.0.1";
// 服务器端口
private final int PORT = 8888;
private Selector selector;
private SocketChannel socketChannel;
private String username;
public GroupChatClient() {
try {
selector = Selector.open();
socketChannel = SocketChannel.open(new InetSocketAddress(HOST, PORT));
socketChannel.configureBlocking(false);
socketChannel.register(selector, SelectionKey.OP_READ);
username = socketChannel.getLocalAddress().toString().substring(1);
System.out.println(username + " ok！");
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 向服务端发送消息
*
* @param info 消息内容
*/
public void sendInfo(String info) {
info = username + "说：" + info;
try {
socketChannel.write(ByteBuffer.wrap(info.getBytes()));
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 从服务端 读取消息
*/
public void readInfo() {
try {
int readChannels = selector.select(2000);
if (readChannels > 0) {
Set<SelectionKey> keys = selector.selectedKeys();
Iterator<SelectionKey> keyInterator = keys.iterator();
while (keyInterator.hasNext()) {
SelectionKey selectionKey = keyInterator.next();
if (selectionKey.isReadable()) {
// 得到读相关通道
SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
socketChannel.read(byteBuffer);
//把buffer中的数据转成字符 串
String messge = new String(byteBuffer.array());
System.out.println( messge.trim());
}
//删除当前selectionKey
keyInterator.remove();
}
} else {
// System.out.println("没有可用通道。。。。")
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
// 启动客户端
GroupChatClient chatClient = new GroupChatClient();
// 启动一个线程每隔2秒读取从服务端发送过来的数据
new Thread() {
@Override
public void run() {
while (true) {
chatClient.readInfo();
try {
Thread.currentThread().sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}.start();
// 发送数据到服务端
Scanner scanner = new Scanner(System.in);
while (scanner.hasNext()) {
String info = scanner.next();
chatClient.sendInfo(info);
}
}
}