netty 例子

客户端：

public class TimeClient {
public void connect(int port, String host){
EventLoopGroup group = new NioEventLoopGroup();
Bootstrap b = new Bootstrap();
b.group(group).channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(new ChildChannelHandler());

try {
ChannelFuture f = b.connect(host, port).sync();
f.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}
finally{
group.shutdownGracefully();
}
}

class ChildChannelHandler extends ChannelInitializer<SocketChannel> {

@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new TimeClientHandler());

}

}
class TimeClientHandler extends ChannelHandlerAdapter {

private final Logger logger = 
Logger.getLogger(TimeClientHandler
.class.getSimpleName());
private ByteBuf firstMessage;

public TimeClientHandler(){
byte[] req = "query".getBytes();
firstMessage = Unpooled.buffer(req.length);
firstMessage.writeBytes(req);
}

@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("now is : " + body);
}

@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
logger.info("Unexpected exception from downstream : " 
+ cause.getMessage());
ctx.close();
}

@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
super.channelActive(ctx);
ctx.writeAndFlush(firstMessage);
}
}

public static void main(String[] args) {
new TimeClient().connect(6666, "127.0.0.1");
}

}

服务端：

public class TimeServer {

public void bind(int port) {
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 1024)
.childHandler(new ChildChannelHandler());

ChannelFuture f = serverBootstrap.bind(port).sync();
f.channel().closeFuture().sync();
} catch (Exception ex) {
System.err.println(ex.getLocalizedMessage());
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}

class ChildChannelHandler extends ChannelInitializer<SocketChannel> {

@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new TimeServerHandler());
}
}

class TimeServerHandler extends ChannelHandlerAdapter {
@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 receive : " + body);
String currentTime = "query".equalsIgnoreCase(body)
? new java.util.Date(System.currentTimeMillis()).toString()
: "bad order";
ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
ctx.write(resp);
}

@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
ctx.close();
}
}

public static void main(String[] args) {
new TimeServer().bind(6666);
}

}