实例要求
- 编写一个 Netty 群聊系统，实现服务器端和客户端之间的数据简单通讯（非阻塞）
- 实现多人群聊
- 服务器端：可以监测用户上线，离线，并实现消息转发功能
- 客户端：通过channel 可以无阻塞发送消息给其它所有用户，同时可以接受其它用户发送的消息(有服务器转发得到)
目的：进一步理解Netty非阻塞网络编程机制
服务端
编写GroupChatServer类
GroupChatServerHandler
private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
public class GroupChatServer {
private int port;//监听端口
public GroupChatServer(int port) {
this.port = port;
}
//编写run方法，处理客户端端请求
public void run() throws InterruptedException {
//创建两个线程组
NioEventLoopGroup bossGroup = new NioEventLoopGroup(1);
NioEventLoopGroup workerGroup = new NioEventLoopGroup(8);
try {
ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 128)
.childOption(ChannelOption.SO_KEEPALIVE, true)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
//获取到pipelineå
ChannelPipeline pipeline = ch.pipeline();
//向pipeline加入解码器
pipeline.addLast("decoder", new StringDecoder());
//向pipeline加入编码器
pipeline.addLast("encoder", new StringEncoder());
//加入自己到业务处理handler
pipeline.addLast(new GroupChatServerHandler());
}
});
System.out.println("Netty 服务器启动");
ChannelFuture channelFuture = bootstrap.bind(port).sync();
//监听关闭
channelFuture.channel().closeFuture().sync();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
public static void main(String[] args) throws InterruptedException {
new GroupChatServer(7000).run();
}
}
public class GroupChatServerHandler extends SimpleChannelInboundHandler<String> {
//定义一个channel组，管理所以到channel
//GlobalEventExecutor.INSTANCE 是全局的事件执行器，单例
private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
//handlerAdded表示连接建立，一旦连接，第一个被执行该方法
//将当前channel加入到channelGroup
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
//将该客户端加入聊天端信息推送给其他在线端客户端。该方法会将channelGroup中所有端channel遍历，并发送信息。因此不需要自己遍历
channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + " 加入聊天" + sdf.format(new Date()) + "\n");
channelGroup.add(channel);
}
//断开连接，将xx客户离开信息推送哥当前在线的客户
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + " 离开了\n");
System.out.println("当前channelGroup大小：" + channelGroup.size());
}
//表示channel处于活动的状态 提示xxx上线
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println(ctx.channel().remoteAddress() + " 上线了～"+sdf.format(new Date()) + "\n");
}
//表示channel处于不活动的状态 提示xxx下线
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
System.out.println(ctx.channel().remoteAddress() + " 离线了～"+sdf.format(new Date()) + "\n");
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
//获取当前channel
Channel channel = ctx.channel();
//遍历channelGroup，根据不同的情况，推送不同的消息 （排除自身）
channelGroup.forEach(ch -> {
if (channel != ch) {//不是当前channel，转发消息
ch.writeAndFlush("[客户]" + channel.remoteAddress() + " 发送了消息：" + msg + sdf.format(new Date()) + "\n");
} else {//自己发送的信息，在自己上如何显示
ch.writeAndFlush("[自己]" + " 发送了消息：" + msg + "\n");
}
});
}
}
客户端
GroupChatClient
public class GroupChatClient {
//属性
private final String host;
private final int port;
public GroupChatClient(String host, int port) {
this.host = host;
this.port = port;
}
public void run() throws InterruptedException {
NioEventLoopGroup group = new NioEventLoopGroup();
Bootstrap bootstrap = new Bootstrap();
try {
bootstrap.group(group)
.channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
//得到pipeline
ChannelPipeline pipeline = ch.pipeline();
//加入相关handler
pipeline.addLast("decoder", new StringDecoder());
pipeline.addLast("encoder", new StringEncoder());
//自定义handler
pipeline.addLast(new GroupChatClientHandler());
}
});
ChannelFuture channelFuture = bootstrap.connect(host, port).sync();
//得到channel
Channel channel = channelFuture.channel();
System.out.println("--------" + channel.localAddress() + "--------");
//客户端需要输入信息，创建一个扫描器
Scanner scanner = new Scanner(System.in);
while (scanner.hasNextLine()){
String msg = scanner.nextLine();
//通过channel发送大服务器端
channel.writeAndFlush(msg+"\r\n");
}
} finally {
group.shutdownGracefully();
}
}
public static void main(String[] args) throws InterruptedException {
new GroupChatClient("127.0.0.1",7000).run();
}
}
public class GroupChatClientHandler extends SimpleChannelInboundHandler<String> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
System.out.println(msg.trim());//取掉两端空格
}
}
测试
© 版权声明
文章版权归作者所有，未经允许请勿转载，侵权请联系 admin@trc20.tw 删除。
THE END
