Netty 是一个广受欢迎的异步事件驱动的 Java 开源网络应用程序框架，用于快速开发可维护的高性能协议服务器和客户端。
详细的介绍见：
本文主要是从一个简单的例子开始，介绍如何快速搭建服务器和客户端的一个简单Demo。
依赖包导入
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
</dependency>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.12.Final</version>
</dependency>
服务端代码
服务端代码已经添加相应的备注
public class Server {
public static void main(String[] args) throws Exception {
//1 创建线两个程组
//一个是用于处理服务器端接收客户端连接的
//一个是进行网络通信的（网络读写的）
EventLoopGroup pGroup = new NioEventLoopGroup();
EventLoopGroup cGroup = new NioEventLoopGroup();
//2 创建辅助工具类，用于服务器通道的一系列配置
ServerBootstrap b = new ServerBootstrap();
b.group(pGroup, cGroup) // 绑定俩个线程组
.channel(NioServerSocketChannel.class) // 指定NIO的模式
.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 3000)
// .option(ChannelOption.TCP_NODELAY, true) // 不延迟
.option(ChannelOption.SO_BACKLOG, 32*1024) // 设置tcp缓冲区
.option(ChannelOption.SO_RCVBUF, 32*1024) // 这是接收缓冲大小
// .option(ChannelOption.RCVBUF_ALLOCATOR, AdaptiveRecvByteBufAllocator.DEFAULT) // 自动动态扩容
// .option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT) // 使用对象池，重用缓冲区
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel sc) throws Exception {
//3 在这里配置具体数据接收方法的处理
sc.pipeline().addLast(new ServerHandler());
}
});
//4 进行绑定
ChannelFuture cf1 = b.bind(8765).sync();
//ChannelFuture cf2 = b.bind(8764).sync();
//5 等待关闭
cf1.channel().closeFuture().sync();
//cf2.channel().closeFuture().sync();
pGroup.shutdownGracefully();
cGroup.shutdownGracefully();
}
}
对应的 ServerHandler 代码如下：
//ChannelHandlerAdapter
public class ServerHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println("server channel active... ");
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg)
throws Exception {
ByteBuf buf = (ByteBuf) msg;
byte[] req = new byte[buf.readableBytes()];
buf.readBytes(req);
String body = new String(req, "utf-8");
System.out.println("Server :" + body );
String response = "进行返回给客户端的响应：" + body ;
// PooledByteBufAllocator pool = new PooledByteBufAllocator();
// PooledByteBufAllocator.DEFAULT.heapBuffer();
// ctx.writeAndFlush(Unpooled.wrappedBuffer(response.getBytes()));
ByteBuf directBuf = Unpooled.directBuffer(1024*10, 1024*32);
directBuf.writeBytes(response.getBytes());
ctx.writeAndFlush(directBuf);
//.addListener(ChannelFutureListener.CLOSE);
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx)
throws Exception {
System.out.println("读完了");
ctx.flush();
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable t)
throws Exception {
System.err.println(t);
ctx.close();
}
}
客户端的代码
客户端代码已经添加相应的备注
public class Client {
public static void main(String[] args) throws Exception{
EventLoopGroup group = new NioEventLoopGroup();
Bootstrap b = new Bootstrap();
b.group(group)
.channel(NioSocketChannel.class)
// .option(ChannelOption.TCP_NODELAY, true) //不延迟
.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 3000)
// .option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT) //内存池
// .option(ChannelOption.RCVBUF_ALLOCATOR, AdaptiveRecvByteBufAllocator.DEFAULT) //自动调整下一次缓冲区建立时分配的空间大小，避免内存的浪费
.option(ChannelOption.SO_SNDBUF, 1024 * 1024)
.option(ChannelOption.SO_RCVBUF, 1024 * 1024)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel sc) throws Exception {
sc.pipeline().addLast(new ClientHandler());
}
});
ChannelFuture cf1 = b.connect("127.0.0.1", 8765).syncUninterruptibly();
// 开始测试代码
cf1.channel().writeAndFlush(Unpooled.copiedBuffer("777".getBytes()));
Thread.sleep(1000);
cf1.channel().writeAndFlush(Unpooled.copiedBuffer("777".getBytes()));
// cf1.channel().writeAndFlush(Unpooled.copiedBuffer("777".getBytes()));
// cf1.channel().writeAndFlush(Unpooled.copiedBuffer("777".getBytes()));
cf1.channel().closeFuture().sync();
group.shutdownGracefully();
}
}
对应的 ClientHandler 代码如下：
public class ClientHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
try {
ByteBuf buf = (ByteBuf) msg;
byte[] req = new byte[buf.readableBytes()];
buf.readBytes(req);
String body = new String(req, "utf-8");
System.out.println("Client :" + body );
String response = "收到服务器端的返回信息：" + body;
} finally {
ReferenceCountUtil.release(msg);
}
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
ctx.close();
}
}
自测试
分别启动服务器端和客户端：
服务器控制台输出内容如下：
Server :777
读完了
Server :777
读完了
客户端控制台输出内容如下：
Client :进行返回给客户端的响应：777
Client :进行返回给客户端的响应：777
成功实现了服务器和客户端的通讯。
文档信息
- 本文作者：Piter Jia
- 本文链接：https://piterjia.github.io/2020/04/08/netty-quickly_start/
- 版权声明：自由转载-非商用-非衍生-保持署名（创意共享3.0许可证）