Netty学习笔记四：NIO实现群聊
作者：互联网
群聊服务端代码
package com.mytest.netty.nio.groupChat;
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 {
//定义相关属性
private Selector selector;
private ServerSocketChannel listenChannel;
private static final int PORT = 6666;
//初始化工作
public GroupChatServer() {
try{
//得到选择器
selector = Selector.open();
//得到ServerSocketChannel
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上
listenChannel.register(selector, SelectionKey.OP_ACCEPT);
}catch (IOException e) {
e.printStackTrace();
}
}
//监听的代码
public void listen(){
try{
while (true) {
int count = selector.select();
if (count > 0) {//有事件处理
Set<SelectionKey> selectionKeys = selector.selectedKeys();
Iterator<SelectionKey> iterator = selectionKeys.iterator();
while (iterator.hasNext()) {
//取出selectionKey
SelectionKey key = iterator.next();
//监听到accpet
if (key.isAcceptable()) {
SocketChannel sc = listenChannel.accept();
//设置非阻塞
sc.configureBlocking(false);
//将该sc注册到selector
sc.register(selector, SelectionKey.OP_READ);
//给出上线提示
System.out.println(sc.getRemoteAddress() + "上线 ");
}
if (key.isReadable()) {//通道发生read事件
//处理读事件
readData(key);
}
//删除当前key，防止重复处理
iterator.remove();
}
} else {//等待
System.out.println("等待中。。。。。");
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
}
}
//读取客户端消息
private void readData(SelectionKey key) {
//定义一个socketChannel
SocketChannel channel = null;
try{
//得到channel
channel = (SocketChannel) key.channel();
//创建Buffer
ByteBuffer buffer = ByteBuffer.allocate(1024);
int count = channel.read(buffer);
//根据count的值做处理
if (count > 0) {
//将缓冲区的数据转为字符串并输出
String msg = new String(buffer.array());
//输出该消息
System.out.println(channel.getRemoteAddress() + "：" + msg);
//向其他客户端转发消息(去掉自己)
sendInfoToOtherClients(msg, channel);
}
} catch (IOException e) {
try{
//处理发送过程中断开链接的情况
System.out.println(channel.getRemoteAddress() + "已离线。。。");
//取消注册
key.cancel();
//关闭通道
channel.close();
}catch (IOException e1) {
e1.printStackTrace();
}
}
}
//转发消息给其他客户（通道）
private void sendInfoToOtherClients(String msg, SocketChannel self) throws IOException{
System.out.println("服务器消息发送中。。。");
for (SelectionKey key : selector.keys()) {
//通过key， 去除对应的SocketChannel
Channel targetChannel = key.channel(); //使用Channel也可以接受，因为SocketChannel实现了Channel
//排除自己的Channel
if (targetChannel instanceof SocketChannel && !self.equals(targetChannel)) {
SocketChannel dest = (SocketChannel) targetChannel;
//将msg 存储到Buffer
ByteBuffer buffer = ByteBuffer.wrap(msg.getBytes());
//将buffer的数据写入到通道中
dest.write(buffer);
}
}
}
public static void main(String[] args) {
//创建一个服务器对象
GroupChatServer chatServer = new GroupChatServer();
//监听
chatServer.listen();
}
}
客户端代码
package com.mytest.netty.nio.groupChat;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Scanner;
public class GroupChatClient {
//定义相关属性
private final String HOST = "127.0.0.1";
private static final int PORT = 6666;
private Selector selector;
private SocketChannel socketChannel;
private String userName;
//构造器
public GroupChatClient() throws IOException {
selector = Selector.open();
//链接服务器
socketChannel = socketChannel.open(new InetSocketAddress(HOST, PORT));
//设置非阻塞
socketChannel.configureBlocking(false);
//将channel注册到selector
socketChannel.register(selector, SelectionKey.OP_READ);
//得到userName
userName = socketChannel.getLocalAddress().toString().substring(1);
System.out.println(userName + "is ok ....");
}
//向服务器发送消息
public void sendInfo(String info){
info = userName + "说：" + info;
try{
socketChannel.write(ByteBuffer.wrap(info.getBytes()));
} catch (IOException e) {
e.printStackTrace();
}
}
//读取从服务端回复的数据
public void readInfo() {
try {
int readChannels = selector.select(2000);
if (readChannels > 0) {//有可以使用的通道
Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
while (iterator.hasNext()) {
SelectionKey key = iterator.next();
if (key.isReadable()) {
//得到相关的通道
SocketChannel sc = (SocketChannel) key.channel();
//得到一个Buffer
ByteBuffer buffer = ByteBuffer.allocate(1024);
//读取
sc.read(buffer);
System.out.println(new String(buffer.array()));
}
}
iterator.remove();
}else {
// System.out.println("没有可用的通道");
}
}catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws IOException {
//启动客户端
GroupChatClient chatClient = new GroupChatClient();
//启动一个线程，每隔3S读取从服务器端发送的数据
new Thread() {
public void run() {
while (true) {
chatClient.readInfo();
try {
Thread.currentThread().sleep(3000);
}catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}.start();
//客户端发送数据给服务端
Scanner scanner = new Scanner(System.in);
while (scanner.hasNextLine()) {
String s = scanner.nextLine();
chatClient.sendInfo(s);
}
}
}
标签：Netty,java,NIO,selector,key,import,群聊,SocketChannel,channel 来源： https://www.cnblogs.com/the-zym/p/14673163.html