package com.shengsiyuan.nio;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.UUID;
public class NioServer {
private static Map<String, SocketChannel> clientMap = new HashMap();
public static void main(String[] args) throws IOException {
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();//创建一个ServerSocketChannel
serverSocketChannel.configureBlocking(false);//非阻塞
ServerSocket serverSocket = serverSocketChannel.socket();//通过服务端的channel获取服务端的socket,
serverSocket.bind(new InetSocketAddress(8899));
Selector selector = Selector.open();//服务端channel注册到选择器上，
//选择器可以关联多个channel对象，这里只有一个channel。
serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);//现在关注服务端channel的连接事件，
while (true) {
try {//异常try()catch{}
selector.select();//阻塞，等着关注的事件发生，返回发生的关注事件的数量。
Set<SelectionKey> selectionKeys = selector.selectedKeys();//一个个的事件，现在只有一个OP_ACCEPT事件，
selectionKeys.forEach(selectionKey -> {
final SocketChannel client;
try {
//OP_ACCEPT事件
if (selectionKey.isAcceptable()) {
//这个selectionKey关联的channel是服务端channel，OP_ACCEPT是服务端channel关注的事件（并注册在选择器上）
//所以这里可以强制转为服务端channel，
ServerSocketChannel server = (ServerSocketChannel) selectionKey.channel();
client = server.accept();//接受连接，真正接收连接之后返回SocketChannel对象，就是与客户端通信的socket，
//对于当前通道，服务端socket就用不上了，用SocketChannel
client.configureBlocking(false);//非阻塞的
//转而把SocketChannel注册到选择器，并关注读事件，
client.register(selector, SelectionKey.OP_READ);
//此时这个选择器有2个socket，一个服务端channel一个SocketChannel，一个关注连接一个关注数据读取，
String key = "【" + UUID.randomUUID().toString() + "】";
clientMap.put(key, client);
//OP_READ事件
} else if (selectionKey.isReadable()) {
client = (SocketChannel) selectionKey.channel();//肯定是客户端关联的socket
ByteBuffer readBuffer = ByteBuffer.allocate(1024);
int count = client.read(readBuffer);//读到buffer
if (count > 0) {
readBuffer.flip();
Charset charset = Charset.forName("utf-8");//编码
//发过来的数据转成string
String receivedMessage = String.valueOf(charset.decode(readBuffer).array());
//打印客户端发过来的数据
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();
//先写到ByteBuffer
ByteBuffer writeBuffer = ByteBuffer.allocate(1024);
writeBuffer.put((senderKey + ": " + receivedMessage).getBytes());
writeBuffer.flip();
//然后buteBuffer写出去到channel
value.write(writeBuffer);
}
}
}
} catch (Exception ex) {
ex.printStackTrace();
}
});
selectionKeys.clear();//事件处理完成之后要清空，否则下次还要处理，就会报空指针。就是iter.remove();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
}
package com.shengsiyuan.nio;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
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.time.LocalDateTime;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class NioClient {
public static void main(String[] args) throws IOException {
try {
SocketChannel socketChannel = SocketChannel.open();//@587
socketChannel.configureBlocking(false);
Selector selector = Selector.open();
//OP_ACCEPT是接受连接，OP_CONNECT是发起连接，
socketChannel.register(selector, SelectionKey.OP_CONNECT);
socketChannel.connect(new InetSocketAddress("127.0.0.1", 8899));
while (true) {
selector.select();//阻塞
Set<SelectionKey> keySet = selector.selectedKeys();
for (SelectionKey selectionKey : keySet) {
//已经建立好了连接
if (selectionKey.isConnectable()) {
SocketChannel client = (SocketChannel) selectionKey.channel();//就是之前的那个socket @587
//连接是否处于进行状态
if (client.isConnectionPending()) {
client.finishConnect();//完成连接，现在连接真正建立好了，
//向服务器发送连接建立好了的消息
ByteBuffer writeBuffer = ByteBuffer.allocate(1024);
writeBuffer.put((LocalDateTime.now() + " 连接成功").getBytes());
//翻转
writeBuffer.flip();
//写到channel
client.write(writeBuffer);
ExecutorService executorService = Executors.newSingleThreadExecutor(
Executors.defaultThreadFactory());//只有一个线程的线程池
executorService.submit(() -> {
while (true) {
try {
writeBuffer.clear();
InputStreamReader input = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(input);
String sendMessage = br.readLine();
//写入到buffer
writeBuffer.put(sendMessage.getBytes());
//翻转
writeBuffer.flip();
//buffer写出去
client.write(writeBuffer);
} catch (Exception ex) {
ex.printStackTrace();
}
}
});
}
//给这个channel注册读取事件，
client.register(selector, SelectionKey.OP_READ);//@587
} else if (selectionKey.isReadable()) {
SocketChannel client = (SocketChannel) selectionKey.channel();//@587
ByteBuffer readBuffer = ByteBuffer.allocate(1024);
int count = client.read(readBuffer);
if (count > 0) {
String receivedMessage = new String(readBuffer.array(), 0, count);//字节数组转字符串
System.out.println(receivedMessage);
}
}
}
keySet.clear();//清除事件，就是清除SelectionKey集合。
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
