需要导包：netty-all-4.1.25.Final
或者导入依赖：
定义一个server类：
public class HelloServer {
public static void main(String[] args) {
// 定义一对线程组
// 主线程组, 用于接受客户端的连接，但是不做任何处理，跟老板一样，不做事
EventLoopGroup bossGroup = new NioEventLoopGroup();
// 从线程组, 老板线程组会把任务丢给他，让手下线程组去做任务
EventLoopGroup workerGroup = new NioEventLoopGroup();
// netty服务器的创建, ServerBootstrap 是一个启动类
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup,workerGroup) // 设置主从线程组
.channel(NioServerSocketChannel.class) // 设置nio的双向通道
.childHandler(new HelloServerInitializer()); // 初始化器，用于处理workerGroup
try {
// 启动server，并且设置8088为启动的端口号，同时启动方式为同步
ChannelFuture channelFuture = serverBootstrap.bind(8088).sync();
// 监听关闭的channel，设置位同步方式
channelFuture.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
初始化器类：
public class HelloServerInitializer extends ChannelInitializer
@Override
protected void initChannel(SocketChannel ch) throws Exception {
// 通过SocketChannel去获得对应的管道
ChannelPipeline pipeline = ch.pipeline();
// 通过管道，添加handler
// HttpServerCodec是由netty自己提供的助手类，可以理解为拦截器
// 当请求到服务端，我们需要做解码，响应到客户端做编码
pipeline.addLast("HttpServerCodec", new HttpServerCodec());
// 添加自定义的助手类，返回 "hello netty~" 助手类名字可写可不写
pipeline.addLast("CustomHandler", new CustomHandler());
}
}
自定义的处理器：
public class CustomHandler extends SimpleChannelInboundHandler
@Override
protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
// 获取channel
Channel channel = ctx.channel();
if(msg instanceof HttpRequest) {
// 显示客户端的远程地址
System.out.println(channel.remoteAddress());
// 定义发送的数据消息
ByteBuf content = Unpooled.copiedBuffer("hello netty",CharsetUtil.UTF_8);
// 构建一个http response
FullHttpResponse resp = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1,HttpResponseStatus.OK,content);
// 为响应增加数据类型和长度
resp.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain");
resp.headers().set(HttpHeaderNames.CONTENT_LENGTH, content.readableBytes());
ctx.writeAndFlush(resp);
}
}
@Override
public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
System.out.println("channel。。。注册");
super.channelRegistered(ctx);
}
@Override
public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
System.out.println("channel。。。移除");
super.channelUnregistered(ctx);
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println("channel。。。活跃");
super.channelActive(ctx);
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
System.out.println("channel。。。不活跃");
super.channelInactive(ctx);
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
System.out.println("channeld读取完毕。。。");
super.channelReadComplete(ctx);
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
System.out.println("用户事件触发。。。");
super.userEventTriggered(ctx, evt);
}
@Override
public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
System.out.println("channel可写更改");
super.channelWritabilityChanged(ctx);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
System.out.println("补货到异常");
super.exceptionCaught(ctx, cause);
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
System.out.println("助手类添加");
super.handlerAdded(ctx);
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
System.out.println("助手类移除");
super.handlerRemoved(ctx);
}
}