netty实现websocket客户端（附：测试服务端代码）

1，客户端启动类

package test3;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.http.DefaultHttpHeaders;
import io.netty.handler.codec.http.HttpClientCodec;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame;
import io.netty.handler.codec.http.websocketx.PingWebSocketFrame;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketClientHandshakerFactory;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketVersion;
import io.netty.handler.ssl.SslContext;
import io.netty.handler.ssl.SslContextBuilder;
import io.netty.handler.ssl.util.InsecureTrustManagerFactory;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URI;

public final class WebSocketClient {

    static final String URL = System.getProperty("url", "ws://127.0.0.1:5688/ws");

    public void connect(String URL, ChannelGroup clients, ChannelHandlerContext ctx) throws Exception {
        URI uri = new URI(URL);
        String scheme = uri.getScheme() == null ? "ws" : uri.getScheme();
        final String host = uri.getHost() == null ? "127.0.0.1" : uri.getHost();
        final int port;
        if (uri.getPort() == -1) {
            if ("ws".equalsIgnoreCase(scheme)) {
                port = 80;
            } else if ("wss".equalsIgnoreCase(scheme)) {
                port = 443;
            } else {
                port = -1;
            }
        } else {
            port = uri.getPort();
        }

        if (!"ws".equalsIgnoreCase(scheme) && !"wss".equalsIgnoreCase(scheme)) {
            System.err.println("Only WS(S) is supported.");
            return;
        }

        final boolean ssl = "wss".equalsIgnoreCase(scheme);
        final SslContext sslCtx;
        if (ssl) {
            sslCtx = SslContextBuilder.forClient().trustManager(InsecureTrustManagerFactory.INSTANCE).build();
        } else {
            sslCtx = null;
        }

        EventLoopGroup group = new NioEventLoopGroup();
        try {
            final WebSocketClientHandler handler = new WebSocketClientHandler(ctx, WebSocketClientHandshakerFactory
                    .newHandshaker(uri, WebSocketVersion.V13, null, false, new DefaultHttpHeaders()));

            Bootstrap b = new Bootstrap();
            b.group(group).channel(NioSocketChannel.class).handler(new ChannelInitializer<SocketChannel>() {
                @Override
                protected void initChannel(SocketChannel ch) {
                    ChannelPipeline p = ch.pipeline();
                    if (sslCtx != null) {
                        p.addLast(sslCtx.newHandler(ch.alloc(), host, port));
                    }
                    p.addLast(new HttpClientCodec(), new HttpObjectAggregator(8192), handler);
                }
            });

            Channel ch = b.connect(uri.getHost(), port).sync().channel();
            handler.handshakeFuture().sync();
            /*
             * String msg = "222"; WebSocketFrame frame = new
             * TextWebSocketFrame(msg); ch.writeAndFlush(frame);
             */
            // ch.writeAndFlush("222");
            BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
            while (true) {
                String msg = console.readLine();
                if (msg == null) {
                    break;
                } else if ("bye".equals(msg.toLowerCase())) {
                    ch.writeAndFlush(new CloseWebSocketFrame());
                    ch.closeFuture().sync();
                    break;
                } else if ("ping".equals(msg.toLowerCase())) {
                    WebSocketFrame frame = new PingWebSocketFrame(Unpooled.wrappedBuffer(new byte[] { 8, 1, 8, 1 }));
                    ch.writeAndFlush(frame);
                } else {
                    WebSocketFrame frame = new TextWebSocketFrame(msg);
                    ch.writeAndFlush(frame);
                }
            }
        } finally {
            group.shutdownGracefully();
        }
    }
}

（2）

package test3;

import java.time.LocalDateTime;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.handler.codec.http.FullHttpResponse;
import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame;
import io.netty.handler.codec.http.websocketx.PongWebSocketFrame;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketClientHandshaker;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketHandshakeException;
import io.netty.util.CharsetUtil;
import io.netty.util.concurrent.GlobalEventExecutor;
import test.SocketHandlerInitializer;

public class WebSocketClientHandler extends SimpleChannelInboundHandler<Object> {

    private Channel outboundChannel;
    private ChannelHandlerContext channel;
    private static ChannelGroup clients = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
    private final WebSocketClientHandshaker handshaker;
    private ChannelPromise handshakeFuture;

    public WebSocketClientHandler(ChannelHandlerContext channel, WebSocketClientHandshaker handshaker) {
        this.handshaker = handshaker;
        this.channel = channel;
    }

    public ChannelFuture handshakeFuture() {
        return handshakeFuture;
    }

    @Override
    public void handlerAdded(ChannelHandlerContext ctx) {
        System.out.println("handlerAdded");
        handshakeFuture = ctx.newPromise();
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        System.out.println("channelActive");
        handshaker.handshake(ctx.channel());
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) {
        System.out.println("WebSocket Client 链接失败!");
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println("channelRead0");
        Channel ch = ctx.channel();
        if (!handshaker.isHandshakeComplete()) {
            try {
                handshaker.finishHandshake(ch, (FullHttpResponse) msg);
                System.out.println("WebSocket Client connected!");
                handshakeFuture.setSuccess();
            } catch (WebSocketHandshakeException e) {
                System.out.println("WebSocket Client failed to connect");
                handshakeFuture.setFailure(e);

            }
            return;
        }

        if (msg instanceof FullHttpResponse) {
            FullHttpResponse response = (FullHttpResponse) msg;
            throw new IllegalStateException("Unexpected FullHttpResponse (getStatus=" + response.getStatus()
                    + ", content=" + response.content().toString(CharsetUtil.UTF_8) + ')');
        }

        WebSocketFrame frame = (WebSocketFrame) msg;
        if (frame instanceof TextWebSocketFrame) {
            TextWebSocketFrame textFrame = (TextWebSocketFrame) frame;
            // resposnse(ctx, frame);

            channel.writeAndFlush(textFrame.text());
            System.out.println("WebSocket Client received message: " + textFrame.text());
        } else if (frame instanceof PongWebSocketFrame) {
            System.out.println("WebSocket Client received pong");
        } else if (frame instanceof CloseWebSocketFrame) {
            System.out.println("WebSocket Client received closing");
            ch.close();
        }
    }

    private void response(ChannelHandlerContext ctx, final WebSocketFrame msg) {
        // 获取客户端传输过来的消息
        String content = msg.toString();
        clients.writeAndFlush(new TextWebSocketFrame("[服务器收到相应]" + LocalDateTime.now() + "接受萨达到消息, 消息为：" + content));

        final Channel inboundChannel = ctx.channel();

        Bootstrap b = new Bootstrap();
        b.group(inboundChannel.eventLoop()).channel(ctx.channel().getClass())
                .handler(new SocketHandlerInitializer(inboundChannel));

        ChannelFuture f = b.connect("127.0.0.1", 5688);
        outboundChannel = f.channel();
        msg.retain();

        ChannelFuture channelFuture = f.addListener(new ChannelFutureListener() {
            public void operationComplete(ChannelFuture future) throws Exception {
                if (future.isSuccess()) {
                    System.out.println("isSuccess:true");
                    outboundChannel.writeAndFlush("2222222222");
                } else {
                    System.out.println("isSuccess：false");
                    inboundChannel.close();
                }
            }
        });
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        if (!handshakeFuture.isDone()) {
            handshakeFuture.setFailure(cause);
        }
        ctx.close();
    }

}

（3）测试用的服务端代码

package com.googosoft.websocket;

import java.io.IOException;
import javax.websocket.DecodeException;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;

@ServerEndpoint("/echo")
public class EchoServer {

    @OnOpen
    public void initSession(Session session) {
    }

    @OnMessage
    public void onMessage(String message, Session session)
        throws IOException, InterruptedException {
        System.out.println("Received: " + message);
        session.getBasicRemote().sendText("This is the first server message");
    }

    @OnError
    public void handleError(Throwable thw) {
        thw.printStackTrace();
        if (thw instanceof DecodeException) {
           System.out.println("Error decoding incoming message: " + ((DecodeException)thw).getText());
       } else {
           System.out.println("Server WebSocket error: " + thw.getMessage());
       }
    }

    @OnClose
    public void processClose(Session session){

    }
}

在测试的时候，服务端的代码我把它放在了一个web项目里面充当服务端

客户端就用的普通的Java项目，在main方法里面建立链接，实现通信