Reference
Maven
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.10.Final</version>
</dependency>
Description
這個例子跟 guide 上的不太相同, 除了原本的 echo 行為.
另外有做讓人 input message, 從 client 送給 server 做 echo.
MainClass
public class EchoServerMain {
public static void main(String[] params) throws Exception {
new Thread(() -> {
try {
new EchoServer(1234).run();
} catch (Exception e) {
e.printStackTrace();
}
}).start();
TimeUnit.SECONDS.sleep(1);
new EchoClient("localhost", 1234).connectRunAndExit();
}
public static class EchoClient {
private final String ip;
private final int port;
EchoClient(String ip, int port) {
this.port = port;
this.ip = ip;
}
public void connectRunAndExit() throws InterruptedException {
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
Bootstrap b = new Bootstrap();
b.group(workerGroup);
b.channel(NioSocketChannel.class);
b.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(new EchoClientHandler());
}
});
ChannelFuture f = b.connect(ip, port).sync();
Channel ch = f.channel();
System.out.println("scan...");
Scanner scanner = new Scanner(System.in);
while (scanner.hasNextLine()) {
String msg = scanner.nextLine();
System.out.println("Input:" + msg);
ByteBuf msgBuffer = Unpooled.wrappedBuffer(msg.getBytes(CharsetUtil.UTF_8));
ch.writeAndFlush(msgBuffer);
}
// Wait until the connection is closed.
f.channel().closeFuture().sync();
} finally {
workerGroup.shutdownGracefully().sync();
}
}
}
public static class EchoServer {
private int port;
public EchoServer(int port) {
this.port = port;
}
public void run() throws Exception {
EventLoopGroup group = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(group)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(new EchoServerHandler());
}
});
ChannelFuture f = b.bind(port).sync();
System.out.println("bind done");
f.channel().closeFuture().sync();
System.out.println("close done");
} finally {
group.shutdownGracefully().sync();
}
}
}
}
EchoClientHandler
public class EchoClientHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext channelHandlerContext, Object msg) throws Exception {
System.out.println("Client receive:" + ((ByteBuf)msg).toString(Charset.defaultCharset()));
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
}
}
EchoServerHandler
public class EchoServerHandler extends ChannelInboundHandlerAdapter {
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
System.out.println("triggered:" + evt);
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println("server receive:" + msg);
ctx.writeAndFlush(msg);
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println("connection active:" + ctx);
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
System.out.println("connection inactive:" + ctx);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
Output
