netty的简单的应用例子

netty的简单的应⽤例⼦⼀、简单的聊天室程序
public class ChatClient {
public static void main(String[] args) throws InterruptedException, IOException {
NioEventLoopGroup nioEventLoopGroup = new NioEventLoopGroup();
try{
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(nioEventLoopGroup).channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline()
// .addLast(new DelimiterBasedFrameDecoder(4096, Delimiters.lineDelimiter()))
.addLast(new LineBasedFrameDecoder(1024))
.addLast(new StringDecoder(CharsetUtil.UTF_8))
.addLast(new StringEncoder(CharsetUtil.UTF_8))
.addLast(new SimpleChannelInboundHandler<String>() {
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception { System.out.println(msg);
}
});
}
});
ChannelFuture future = bootstrap.connect("localhost", 8888).sync();
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
Channel channel = future.channel();
while(true){
channel.writeAndFlush(br.readLine()+"\n");
}
}finally{
nioEventLoopGroup.shutdownGracefully().sync();
}
}
}
public class ChatServer {
public static void main(String[] args) throws InterruptedException {
NioEventLoopGroup bossGroup = new NioEventLoopGroup();
NioEventLoopGroup workerGroup = new NioEventLoopGroup();
try{
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline()
// .addLast(new DelimiterBasedFrameDecoder(4096, Delimiters.lineDelimiter()))
.addLast(new LineBasedFrameDecoder(1024))
.addLast(new StringDecoder(CharsetUtil.UTF_8))
.addLast(new StringEncoder(CharsetUtil.UTF_8))
.addLast(new ChatServerHandler());
}
});
ChannelFuture future = serverBootstrap.bind(8888).sync();
future.channel().closeFuture().sync();
}finally{
bossGroup.shutdownGracefully().sync();
workerGroup.shutdownGracefully().sync();
}
}
}
public class ChatServerHandler extends SimpleChannelInboundHandler<String>{
public static final ChannelGroup group = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE); @Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
Channel channel = ctx.channel();
group.forEach(ch ->{
if(channel != ch){
ch.writeAndFlush(channel.remoteAddress()+": "+ msg+"\n");
}else{
ch.writeAndFlush("⾃⼰： "+msg+"\n");
}
});
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
group.writeAndFlush("服务器： "+channel.remoteAddress()+"加⼊");
group.add(channel);
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
group.writeAndFlush("服务器： "+channel.remoteAddress() + "离开");
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println(ctx.channel().remoteAddress()+" 上线");
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
System.out.println(ctx.channel().remoteAddress()+" 下线");
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
⼆、使⽤netty传递对象，使⽤jdk⾃带的序列化
public class SubReqClient {
public static void main(String[] args) {
start();
}
public static void start(){
NioEventLoopGroup group = new NioEventLoopGroup();
try{
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(group).channel(NioSocketChannel.class)
.handler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline()
.addLast("decoder", new ObjectDecoder(ClassResolvers.cacheDisabled(
this.getClass().getClassLoader()
)))
.addLast("encoder", new ObjectEncoder())
.addLast(new SimpleChannelInboundHandler<Object>() {
@Override
protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { System.out.println(msg);
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
User user = new User();
user.setName("runtu");
ctx.writeAndFlush(user);
}
});
}
});
ChannelFuture future = bootstrap.connect("localhost", 8888).sync();
future.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}finally{
group.shutdownGracefully();
}
}
}
public class SubReqServer {
public static void main(String[] args) {
start();
}
public static void start(){
NioEventLoopGroup bossGroup = new NioEventLoopGroup();
NioEventLoopGroup workGroup = new NioEventLoopGroup();
try{
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup,workGroup).channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline()
.addLast("decoder", new ObjectDecoder(ClassResolvers.cacheDisabled(
this.getClass().getClassLoader()
)))
.addLast("encoder", new ObjectEncoder())
.addLast(new SimpleChannelInboundHandler<Object>() {
@Override
protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { User user1 = (User)msg;
System.out.println(user1.getName());
User user = new User();
user.setName("AQ");
ctx.writeAndFlush(user);
}
});
}
});
ChannelFuture future = serverBootstrap.bind(8888).sync();
future.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}finally{
bossGroup.shutdownGracefully();
workGroup.shutdownGracefully();
}
}
}
public class User implements Serializable{
private String name;
private int age;
private String address;
public String getName() {
return name;
public void setName(String name) {
= name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User [name=" + name + ", age=" + age + ", address=" + address + "]";
}
}
三、使⽤messagepack进⾏序列化传递实体对象
由于java⾃带的序列化⼯具有着性能低、序列化后的码流⼤且不⽀持跨语⾔等各种缺陷，所以我们使⽤Msgpack库来进⾏序列化然后进⾏数据的传输。

我们需要额外引⼊两个jar包javassist-3.18.1-GA.jar 和msgpack-0.6.12.jar
public class NioClient {
public static void main(String[] args) throws InterruptedException {
NioEventLoopGroup group = new NioEventLoopGroup();
try{
Bootstrap bootStrap = new Bootstrap();
bootStrap.group(group).channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.option(ChannelOption.CONNECT_TIMEOUT_MILLIS,3000)
.handler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline()
.addLast("frameDecoder",new LengthFieldBasedFrameDecoder(1024, 0, 2,0,2))
.addLast(new MsgpackDecoder())
.addLast("frameEncoder",new LengthFieldPrepender(2))
.addLast(new MsgpackEncoder())
.addLast(new ClientHandler());
}
});
ChannelFuture future = bootStrap.connect("localhost", 9999).sync();
future.channel().closeFuture().sync();
}finally{
group.shutdownGracefully();
}
}
}
public class ClientHandler extends SimpleChannelInboundHandler {
@Override
public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println(msg);
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
//发送50个UserInfo给服务器，由于启⽤了粘包/拆包⽀持，所以这⾥连续发送多个也不会出现粘包的现象。

for (int i = 0; i < 50; i++) {
User user = new User();
user.setName("张三"+i);
ctx.write(user);
}
ctx.flush();
System.out.println("-----------------send over-----------------");
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
System.out.println("error");
}
}
public class NioServer {
public static void main(String[] args) throws InterruptedException {
NioEventLoopGroup bossGroup = new NioEventLoopGroup();
NioEventLoopGroup workGroup = new NioEventLoopGroup();
try{
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workGroup).channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline()
.addLast("frameDecoder",new LengthFieldBasedFrameDecoder(1024, 0, 2,0,2))
.addLast(new MsgpackDecoder())
.addLast("frameEncoder",new LengthFieldPrepender(2))
.addLast(new MsgpackEncoder())
.addLast(new ServerHandler());
}
});
ChannelFuture future = serverBootstrap.bind(9999).sync();
future.channel().closeFuture().sync();
}finally{
bossGroup.shutdownGracefully();
workGroup.shutdownGracefully();
}
}
}
public class ServerHandler extends SimpleChannelInboundHandler {
@Override
public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
try {
//直接输出msg
System.out.println(msg.toString());
User user = new User();
user.setName("李四");
//回复has receive 给客户端
ctx.write(user);
} catch (Exception e) {
e.printStackTrace();
}finally {
}
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}
}
public class MsgpackDecoder extends MessageToMessageDecoder<ByteBuf>{
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf buf, List<Object> out) throws Exception { final int length = buf.readableBytes();
final byte[] array = new byte[length];
buf.getBytes(buf.readerIndex(), array,0,length);
MessagePack messagePack = new MessagePack();
out.add(messagePack.read(array));
}
}
public class MsgpackEncoder extends MessageToByteEncoder<Object>{
@Override
protected void encode(ChannelHandlerContext ctx, Object obj, ByteBuf out) throws Exception {
MessagePack messagePack = new MessagePack();
byte[] info = messagePack.write(obj);
out.writeBytes(info);
}
}
public class User {
private String name;
private int age;
private String address;
public String getName() {
return name;
}
public void setName(String name) {
= name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User [name=" + name + ", age=" + age + ", address=" + address + "]";
}
}
四、使⽤Marshalling来对对象进⾏序列化，这种序列化⽅式需要对想实现Serializable接⼝
需要引⼊jar包 jboss-marshalling-2.0.6.Final.jar和jboss-marshalling-serial-2.0.6.Final.jar
public class SubReqClient {
public static void main(String[] args) {
start();
}
public static void start(){
NioEventLoopGroup group = new NioEventLoopGroup();
try{
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(group).channel(NioSocketChannel.class)
.handler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline().addLast(MarshallingCodeCFactory.buildMarshallingDecoder())
.addLast(MarshallingCodeCFactory.buildMarshallingEncoder())
.addLast(new SimpleChannelInboundHandler<Object>() {
@Override
protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { System.out.println(msg);
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
User user = new User();
user.setName("runtu");
ctx.writeAndFlush(user);
}
});
}
});
ChannelFuture future = bootstrap.connect("localhost", 8888).sync();
future.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}finally{
group.shutdownGracefully();
}
}
}
public class SubReqServer {
public static void main(String[] args) {
start();
}
public static void start(){
NioEventLoopGroup bossGroup = new NioEventLoopGroup();
NioEventLoopGroup workGroup = new NioEventLoopGroup();
try{
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup,workGroup).channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline().addLast(MarshallingCodeCFactory.buildMarshallingDecoder())
.addLast(MarshallingCodeCFactory.buildMarshallingEncoder())
.addLast(new SimpleChannelInboundHandler<Object>() {
@Override
protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { User user1 = (User)msg;
System.out.println(user1.getName());
User user = new User();
user.setName("AQ");
ctx.writeAndFlush(user);
}
});
}
});
ChannelFuture future = serverBootstrap.bind(8888).sync();
future.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}finally{
bossGroup.shutdownGracefully();
workGroup.shutdownGracefully();
}
}
}
public class MarshallingCodeCFactory {
public static MarshallingDecoder buildMarshallingDecoder(){
final MarshallerFactory factory = Marshalling.getProvidedMarshallerFactory("serial");
final MarshallingConfiguration configuration = new MarshallingConfiguration();
configuration.setVersion(5);
DefaultUnmarshallerProvider provider = new DefaultUnmarshallerProvider(factory, configuration); MarshallingDecoder decoder = new MarshallingDecoder(provider,1024);
return decoder;
}
public static MarshallingEncoder buildMarshallingEncoder(){
final MarshallerFactory factory = Marshalling.getProvidedMarshallerFactory("serial");
final MarshallingConfiguration configuration = new MarshallingConfiguration();
configuration.setVersion(5);
MarshallerProvider provider = new DefaultMarshallerProvider(factory, configuration);
MarshallingEncoder encoder = new MarshallingEncoder(provider);
return encoder;
}
}
public class User implements Serializable{
private String name;
private int age;
private String address;
public String getName() {
return name;
}
public void setName(String name) {
= name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User [name=" + name + ", age=" + age + ", address=" + address + "]";
}
}
五、简单的http⽂件服务器
public class HttpServer {
public static void main(String[] args) {
start();
}
public static void start(){
NioEventLoopGroup bossGroup = new NioEventLoopGroup();
NioEventLoopGroup workGroup = new NioEventLoopGroup();
try{
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup,workGroup).channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline()
.addLast(new HttpRequestDecoder())
.addLast(new HttpObjectAggregator(65535))
.addLast(new HttpResponseEncoder())
.addLast(new ChunkedWriteHandler())
.addLast(new FileServerHandler1());
}
});
ChannelFuture future = serverBootstrap.bind(8888).sync();
future.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}finally{
bossGroup.shutdownGracefully();
workGroup.shutdownGracefully();
}
}
}
public class FileServerHandler1 extends SimpleChannelInboundHandler<FullHttpRequest>{
@Override
protected void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception { if(request.uri().equals("/favicon.ico")){
return;
}
if(request.method() == HttpMethod.GET){
String uri = request.uri();
if(uri.startsWith("/file")){
File file = new File("D:\\12306Bypass\\使⽤须知.txt");
RandomAccessFile randomAccessFile = null;
randomAccessFile = new RandomAccessFile(file, "r");
long fileLength = randomAccessFile.length();
HttpResponse response = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE)
.set("Content-Length", fileLength)
.set("Content-Type","text/html")
.set("Content-Disposition", "attachment;fileName="+"a.txt");
ctx.write(response);
ctx.write(new ChunkedFile(randomAccessFile, 0,fileLength,8192),ctx.newProgressivePromise());
ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
}else{
FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK); response.headers()
.set("Content-Type", "text/plain;charset=utf-8")
.set("Content_Length", response.content().readableBytes())
.set("aaa", "cccc");
response.content().writeBytes(Unpooled.copiedBuffer("服务器返回信息",CharsetUtil.UTF_8));
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
}
}
private static void setContentTypeHeader(HttpResponse response, File file){
MimetypesFileTypeMap mimetypesFileTypeMap = new MimetypesFileTypeMap();
response.headers().set(HttpHeaderNames.CONTENT_TYPE, mimetypesFileTypeMap.getContentType(file.getPath())); }
}
六、netty编写websocket服务器
public class WebSocketServer {
public static void main(String[] args) throws InterruptedException {
NioEventLoopGroup bossGroup = new NioEventLoopGroup();
NioEventLoopGroup workerGroup = new NioEventLoopGroup();
try{
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup,workerGroup).channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline()
.addLast(new HttpServerCodec())
.addLast(new HttpObjectAggregator(65536))
.addLast(new ChunkedWriteHandler())
.addLast(new WebSocketServerHandler());
}
});
ChannelFuture future = serverBootstrap.bind(8080).sync();
future.channel().closeFuture().sync();
}finally{
bossGroup.shutdownGracefully().sync();
workerGroup.shutdownGracefully().sync();
}
}
}
public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object>{
private WebSocketServerHandshaker handshaker;
@Override
protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
if(msg instanceof FullHttpRequest){
HandleHttpRequest(ctx,(FullHttpRequest)msg);
}
if(msg instanceof WebSocketFrame){
handleWebSocket(ctx,(WebSocketFrame)msg);
}
}
private void HandleHttpRequest(ChannelHandlerContext ctx,FullHttpRequest request){
WebSocketServerHandshakerFactory factory = new WebSocketServerHandshakerFactory(
"ws://localhost:8888/websocket",null,false);
handshaker = factory.newHandshaker(request);
if(handshaker == null){
WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
}else{
handshaker.handshake(ctx.channel(),request);
}
}
private void handleWebSocket(ChannelHandlerContext ctx,WebSocketFrame frame){
if(frame instanceof CloseWebSocketFrame){
handshaker.close(ctx.channel(), (CloseWebSocketFrame)frame.retain());
}
if(frame instanceof PingWebSocketFrame){
ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));
return;
}
if(!(frame instanceof TextWebSocketFrame)){
return;
}
String requestStr = ((TextWebSocketFrame) frame).text();
System.out.println(requestStr);
ctx.channel().writeAndFlush(new TextWebSocketFrame("欢迎使⽤netty websocket： "+ LocalDateTime.now())); }
}
<html>
<head>
<meta charset="UTF-8">
Netty WebSocket服务器
<head>
<body>
<script type="text/javascript">
var socket;
if(!window.WebSocket){
window.WebSocket = window.MozWebSocket;
}
if(window.WebSocket){
socket = new WebSocket("ws://localhost:8080/websocket");
socket.onmessage = function(event){
var ta = document.getElementById('responseText');
ta.value = '';
ta.value = event.data;
}
socket.onopen = function(event){
var ta = document.getElementById('responseText');
ta.value = "打开WebSocket服务器正常";
}
socket.onclose = function(event){
var ta = document.getElementById('responseText');
ta.value = "webSocket 关闭";
}
}
function send(){
if(socket.readyState == WebSocket.OPEN){
var message = document.getElementById('message').value;
socket.send(message);
}else{
alert("WebSocket 链接未建⽴成功！！");
}
}
</script>
<form onsubmit="return false;">
<input id="message" type="text" name = "message" value="Netty最佳实践"/> <br/><br/>
<input type="button" value="发送" onclick="send()"/>
<hr color="blue"/>
<h3>服务器应答消息</h3>
<textarea id="responseText" style="width:500px;height:300px;"></textarea>
</form>
</body>
</html>。