目录
学了一段时间的netty知识，现在通过这个基于console的程序来对netty的相关接口做个简单的应用。
准备
依赖
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.44.Final</version>
</dependency>
代码实现
我们都知道，一个典型的netty程序绝大部分使基于以下三部曲来走的；
- server/client 启动类
- xxxInitializer （implements ChannelInitializer<?> ）
- xxxChannelHandler (implememts SimpleChannelInboundHandler<?>)
按照以上的三部曲思路，就可以实现自己的网络程序了。
Server端实现
server启动类
public class MyChatServer {
public static void main(String[] args) {
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new MyChatServerInitializeor());
ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();
channelFuture.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
}finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
serverChannelInitializer
public class MyChatServerInitializer extends ChannelInitializer<SocketChannel> {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
ChannelPipeline pipeline = socketChannel.pipeline();
// 粘包、粘包处理器
pipeline.addLast("DelimiterBasedFrameDecoder", new DelimiterBasedFrameDecoder(4096, Delimiters.lineDelimiter()));
pipeline.addLast("StringDecoder", new StringDecoder(CharsetUtil.UTF_8));
pipeline.addLast("StringEncoder", new StringEncoder(CharsetUtil.UTF_8));
pipeline.addLast(new MyServerChannelHandler());
}
}
serverChannelHandler
public class MyServerChannelHandler extends SimpleChannelInboundHandler<String> {
/**
* 保存channel对象
*/
private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
private static final String DATE_PARTTEN = "yyyy-MM-dd HH:mm:ss:SSS";
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
Channel channel = ctx.channel();
channelGroup.forEach(ch -> {
// 当前遍历的channel不是发送msg的channel对象。则向其他客户端广播
if (channel != ch) {
ch.writeAndFlush(channel.remoteAddress() + ", 发送的消息" + msg + "\n");
} else {
ch.writeAndFlush("[自己] " + msg + " \n");
}
});
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
System.out.println(channel.remoteAddress() + " 上线了！");
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
System.out.println(channel.remoteAddress() + " 离开了！");
}
/**
* 客户端链接建立的时候调用
* @param ctx
* @throws Exception
*/
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
//super.handlerAdded(ctx);
// 服务端与客户端建立
Channel channel = ctx.channel();
// 向其他链接的客户端发送广播信息
SocketAddress socketAddress = channel.remoteAddress();
String date = DateTimeFormatter.ofPattern(DATE_PARTTEN).format(LocalDateTime.now());
// 向channelGroup中的每一个channel对象发送一个消息
channelGroup.writeAndFlush(date + " [服务器] - " + socketAddress + " 加入 \n");
// 保存该客户端链接
channelGroup.add(channel);
}
/**
* 链接断开
* @param ctx
* @throws Exception
*/
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
String date = DateTimeFormatter.ofPattern(DATE_PARTTEN).format(LocalDateTime.now());
channelGroup.writeAndFlush(date + " [服务器] - " + channel.remoteAddress() + " 离开 \n");
}
/**
* 客户端注册进来
* @param ctx
* @throws Exception
*/
@Override
public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
super.channelRegistered(ctx);
}
@Override
public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
super.channelUnregistered(ctx);
}
}
client 端实现
client启动类
public class MyChatClient {
public static void main(String[] args) {
EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(eventLoopGroup).channel(NioSocketChannel.class)
.handler(new MyClientChannelInitializor());
ChannelFuture channelFuture = bootstrap.connect("localhost", 8899).sync();
Channel channel = channelFuture.channel();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
for (; ; ) {
channel.writeAndFlush(bufferedReader.readLine() + "\r\n");
}
} catch (InterruptedException | IOException e) {
e.printStackTrace();
} finally {
eventLoopGroup.shutdownGracefully();
}
}
}
clientChannelInitializer
public class MyClientChannelInitializer extends ChannelInitializer<SocketChannel> {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast("DelimiterBasedFrameDecoder", new DelimiterBasedFrameDecoder(4096, Delimiters.lineDelimiter()));
pipeline.addLast("StringDecoder", new StringDecoder(CharsetUtil.UTF_8));
pipeline.addLast("StringEncoder", new StringEncoder(CharsetUtil.UTF_8));
pipeline.addLast(new MyChatClientChannelHandler());
}
}
clientChannelHandler
public class MyChatClientChannelHandler extends SimpleChannelInboundHandler<String> {
// 直接打印服务端返回的消息
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
System.out.println(msg);
}
}