10、netty結合websocket完成消息的單發和羣發

注：源代碼來自享學課堂，略有修改，學習之後所做筆記，方便回顧，也給大家一個參考

服務端

主函數

和普通的服務代碼相同，這裏加上了ssl的支持，如果不需要ssl支持，默認是false

package com.gg.socket.netty.server;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.ssl.SslContext;
import io.netty.handler.ssl.SslContextBuilder;
import io.netty.handler.ssl.util.SelfSignedCertificate;
import io.netty.util.concurrent.ImmediateEventExecutor;

/**
 * @Description WebSecketServer
 * @Author honry.guan
 * @Date 2020/5/26 17:22
 */
public class WebSocketServer {
    /**
     * 創建DefaultChannelGroup,保存已有鏈接socketChannel，羣發和一對一功能可以使用
     */
    public static final ChannelGroup CHANNEL_GROUP = new DefaultChannelGroup(ImmediateEventExecutor.INSTANCE);

    /**
     * 是否啓用ssl，即https
     */
    public static final boolean SSL = false;

    /**
     * 通過ssl訪問8443，否則就訪問8080
     */
    public static final int PORT = Integer.parseInt(System.getProperty("port", SSL ? "8443" : "8080"));

    public static void main(String[] args) throws Exception {
        // SSL配置
        final SslContext sslContext;
        if (SSL) {
            SelfSignedCertificate ssc = new SelfSignedCertificate();
            sslContext = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey()).build();
        } else {
            sslContext = null;
        }

        // 一個線程負責接受新的連接，一個負責處理讀寫
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new WebSocketServerInitializer(sslContext, CHANNEL_GROUP));

            Channel ch = b.bind(PORT).sync().channel();
            System.out.println("打開瀏覽器訪問： " + (SSL ? "https" : "http") + "://127.0.0.1:" + PORT + '/');
            ch.closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

WebSocketServerInitializer

websocket需要藉助http握手支持

package com.gg.socket.netty.server;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketServerCompressionHandler;
import io.netty.handler.ssl.SslContext;

/**
 * @Description WebSocketServerInitializer
 * @Author honry.guan
 * @Date 2020/5/26 17:22
 */
public class WebSocketServerInitializer extends ChannelInitializer<SocketChannel> {
    private final ChannelGroup group;

    /**
     * websocket訪問路徑
     */
    public static final String WEBSOCKET_PATH = "/websocket";

    /**
     * ssl支持
     */
    private final SslContext sslCtx;

    public WebSocketServerInitializer(SslContext sslCtx, ChannelGroup group) {
        this.sslCtx = sslCtx;
        this.group = group;
    }
    @Override
    protected void initChannel(SocketChannel socketChannel) throws Exception {
        ChannelPipeline pipeline = socketChannel.pipeline();
        if(sslCtx != null){
            pipeline.addLast(sslCtx.newHandler((socketChannel.alloc())));
        }

        //http握手支持
        pipeline.addLast(new HttpServerCodec());
        pipeline.addLast(new HttpObjectAggregator(655536));

        //netty提供的，支持websocket應答數據壓縮傳輸
        pipeline.addLast(new WebSocketServerCompressionHandler());
        //netty提供，對整個websocket的通信進行了初始化（發現http保溫中國有升級爲websocket的請你去，包括握手，以及後面的一些通信控制）
        pipeline.addLast(new WebSocketServerProtocolHandler(WEBSOCKET_PATH,null,true));

        //瀏覽器訪問是，展示index頁面,通過代碼生成的HTML頁面
        pipeline.addLast(new ProcessWsIndexPageHandler(WEBSOCKET_PATH));

        //對websocket的數據記性處理
        pipeline.addLast(new ProcessWsFrameHandler(group));
    }
}

ProcessWsIndexPageHandler

通過http請求訪問：8080/的時候，會返回一個HTML頁面

package com.gg.socket.netty.server;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.handler.codec.http.*;
import io.netty.handler.ssl.SslHandler;
import io.netty.util.CharsetUtil;

import static io.netty.handler.codec.http.HttpResponseStatus.NOT_FOUND;

/**
 * @Description ProcessWsIndexPageHandler
 * @Author honry.guan
 * @Date 2020/5/26 17:23
 */
public class ProcessWsIndexPageHandler extends SimpleChannelInboundHandler<FullHttpRequest> {
    private final String webSocketPath;

    public ProcessWsIndexPageHandler(String websocketPath) {
        this.webSocketPath = websocketPath;
    }

    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, FullHttpRequest fullHttpRequest) throws Exception {
        //處理髮送錯誤或者無法解析的http請求
        if (!fullHttpRequest.decoderResult().isSuccess()) {
            sendHttpResponse(channelHandlerContext, fullHttpRequest, new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
            return;
        }

        //只允許get請求
        if (fullHttpRequest.method() != HttpMethod.GET) {
            sendHttpResponse(channelHandlerContext, fullHttpRequest, new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.FORBIDDEN));
            return;
        }

        //發送index頁面內容
        if ("/".equals(fullHttpRequest.getUri()) || "index.html".equals(fullHttpRequest.getUri())) {
            //生成websocket的訪問地址，寫入index頁面中
            String webSocketLocation = getWebSocketLocation(channelHandlerContext.pipeline(), fullHttpRequest,
                    webSocketPath);
            System.out.println("webSocketLocation:" + webSocketLocation);

            //生成index頁面的具體內容，發送瀏覽器
            ByteBuf byteBuf = MakeIndexPage.getContent(webSocketLocation);
            FullHttpResponse res = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, byteBuf);

            res.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html;charset=utf-8");
            HttpUtil.setContentLength(res, byteBuf.readableBytes());

            sendHttpResponse(channelHandlerContext, fullHttpRequest, res);
        } else {
            sendHttpResponse(channelHandlerContext, fullHttpRequest, new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, NOT_FOUND));
        }
    }

    private String getWebSocketLocation(ChannelPipeline pipeline, FullHttpRequest fullHttpRequest, String path) {
        String protocol = "ws";
        if (pipeline.get(SslHandler.class) != null) {
            protocol = "wss";
        }
        return protocol + "://" + fullHttpRequest.headers().get(HttpHeaderNames.HOST) + path;
    }

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

    private void sendHttpResponse(ChannelHandlerContext channelHandlerContext, FullHttpRequest fullHttpRequest, FullHttpResponse fullHttpResponse) {
        //對錯誤的請求進行處理
        if (fullHttpResponse.status().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(fullHttpResponse.status().toString(), CharsetUtil.UTF_8);
            fullHttpResponse.content().writeBytes(buf);
            buf.release();
            HttpUtil.setContentLength(fullHttpResponse, fullHttpRequest.content().readableBytes());
        }

        //發送應答
        ChannelFuture f = channelHandlerContext.channel().writeAndFlush(fullHttpResponse);
        //對於不是長鏈接或者錯誤的額請求直接關閉連接
        if (!HttpUtil.isKeepAlive(fullHttpRequest) || fullHttpResponse.status().code() != 200) {
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }
}

ProcessWsFrameHandler

對瀏覽器或者客戶端發送的消息進行處理，再對當前channel或者所有連接上的客戶端拳法消息

package com.gg.socket.netty.server;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.group.ChannelGroup;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;

import java.util.Locale;
import java.util.logging.Logger;


/**
 * @Description ProcessWsFrameHandler
 * @Author honry.guan
 * @Date 2020/5/26 17:23
 */
public class ProcessWsFrameHandler extends SimpleChannelInboundHandler<WebSocketFrame> {
    private final ChannelGroup group;

    public ProcessWsFrameHandler(ChannelGroup group) {
        this.group = group;
    }
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, WebSocketFrame frame) throws Exception {
        // 判斷是否是文本幀，目前只處理文本幀
        if(frame instanceof TextWebSocketFrame){
            String request = ((TextWebSocketFrame)frame).text();
            System.out.println("服務端收到消息：channelId="+ctx.channel().id()+" 消息:" + request);

            //這個是對當前channel的單發消息
            ctx.channel().writeAndFlush(new TextWebSocketFrame(("客戶端收到單發消息："+request).toUpperCase(Locale.CHINA)));
            //下面是羣發，group保存的是添加進來的channel
            group.writeAndFlush(new TextWebSocketFrame(("客戶端收到羣發消息："+request).toUpperCase(Locale.CHINA)));

        }else{
            String message = "不支持的文本類型:"+ frame.getClass().getName();
            throw new UnsupportedOperationException(message);
        }
    }

    /**
     * 重寫自定義處理事件
     * @param ctx
     * @param evt
     * @throws Exception
     */
    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        //檢測事件，如果握手成功事件，做業務處理
        if(evt == WebSocketServerProtocolHandler.ServerHandshakeStateEvent.HANDSHAKE_COMPLETE){
            //通知所有已經連接的websocket客戶端那新的客戶端已經連接上了
            group.writeAndFlush(new TextWebSocketFrame("客戶端："+ctx.channel().id()+"連接上了"));
            //將新的websocket channel添加到channelgroup中，一遍他客戶已接收所有的消息
            group.add(ctx.channel());
        }else{
            super.userEventTriggered(ctx,evt);
        }
    }
}

MakeIndexPage

生成html的工具類，當然也可以自己新建一個HTML文本來訪問服務器

package com.gg.socket.netty.server;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.util.CharsetUtil;

public final class MakeIndexPage {

    private static final String NEWLINE = "\r\n";

    public static ByteBuf getContent(String webSocketLocation) {
        return Unpooled.copiedBuffer(
                "<html><head><title>Web Socket Test</title></head>"
                        + NEWLINE +
                        "<body>" + NEWLINE +
                        "<script type=\"text/javascript\">" + NEWLINE +
                        "var socket;" + NEWLINE +
                        "if (!window.WebSocket) {" + NEWLINE +
                        "  window.WebSocket = window.MozWebSocket;" + NEWLINE +
                        '}' + NEWLINE +
                        "if (window.WebSocket) {" + NEWLINE +
                        "  socket = new WebSocket(\"" + webSocketLocation + "\");"
                        + NEWLINE +
                        "  socket.onmessage = function(event) {" + NEWLINE +
                        "    var ta = document.getElementById('responseText');"
                        + NEWLINE +
                        "    ta.value = ta.value + '\\n' + event.data" + NEWLINE +
                        "  };" + NEWLINE +
                        "  socket.onopen = function(event) {" + NEWLINE +
                        "    var ta = document.getElementById('responseText');"
                        + NEWLINE +
                        "    ta.value = \"Web Socket opened!\";" + NEWLINE +
                        "  };" + NEWLINE +
                        "  socket.onclose = function(event) {" + NEWLINE +
                        "    var ta = document.getElementById('responseText');"
                        + NEWLINE +
                        "    ta.value = ta.value + \"Web Socket closed\"; "
                        + NEWLINE +
                        "  };" + NEWLINE +
                        "} else {" + NEWLINE +
                        "  alert(\"Your browser does not support Web Socket.\");"
                        + NEWLINE +
                        '}' + NEWLINE +
                        NEWLINE +
                        "function send(message) {" + NEWLINE +
                        "  if (!window.WebSocket) { return; }" + NEWLINE +
                        "  if (socket.readyState == WebSocket.OPEN) {" + NEWLINE +
                        "    socket.send(message);" + NEWLINE +
                        "  } else {" + NEWLINE +
                        "    alert(\"The socket is not open.\");" + NEWLINE +
                        "  }" + NEWLINE +
                        '}' + NEWLINE +
                        "</script>" + NEWLINE +
                        "<form οnsubmit=\"return false;\">" + NEWLINE +
                        "<input type=\"text\" name=\"message\" " +
                        "value=\"Hello, World!\"/>" +
                        "<input type=\"button\" value=\"Send Web Socket Data\""
                        + NEWLINE +
                        "       οnclick=\"send(this.form.message.value)\" />"
                        + NEWLINE +
                        "<h3>Output</h3>" + NEWLINE +
                        "<textarea id=\"responseText\" " +
                        "style=\"width:500px;height:300px;\"></textarea>"
                        + NEWLINE +
                        "</form>" + NEWLINE +
                        "</body>" + NEWLINE +
                        "</html>" + NEWLINE, CharsetUtil.US_ASCII);
    }

}

生成之後的HTML代碼，也可以自定義一個html文件，直接打開瀏覽器

<html><head><title>Web Socket Test</title></head>
<body>
<script type="text/javascript">
var socket;
if (!window.WebSocket) {
  window.WebSocket = window.MozWebSocket;
}
if (window.WebSocket) {
  socket = new WebSocket("ws://127.0.0.1:8080/websocket");
  socket.onmessage = function(event) {
    var ta = document.getElementById('responseText');
    ta.value = ta.value + '\n' + event.data
  };
  socket.onopen = function(event) {
    var ta = document.getElementById('responseText');
    ta.value = "Web Socket opened!";
  };
  socket.onclose = function(event) {
    var ta = document.getElementById('responseText');
    ta.value = ta.value + "Web Socket closed"; 
  };
} else {
  alert("Your browser does not support Web Socket.");
}

function send(message) {
  if (!window.WebSocket) { return; }
  if (socket.readyState == WebSocket.OPEN) {
    socket.send(message);
  } else {
    alert("The socket is not open.");
  }
}
</script>
<form οnsubmit="return false;">
<input type="text" name="message" value="Hello, World!"/><input type="button" value="Send Web Socket Data"
       οnclick="send(this.form.message.value)" />
<h3>Output</h3>
<textarea id="responseText" style="width:500px;height:300px;"></textarea>
</form>
</body>
</html>

通過瀏覽器直接發送和接收消息

啓動服務，訪問http://127.0.0.1:8080/，這個時候就能夠和服務器進行通信了，如圖

服務端收到消息：

channelId=c7882173 消息:Hello, World!

 

通過自定義客戶端發送和接收消息

主函數

package com.gg.socket.client;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
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.*;
import io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketClientCompressionHandler;
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;

/**
 * @Description WebSocketClient
 * @Author honry.guan
 * @Date 2020/5/25 10:47
 */
public class WebSocketClient {
    public static final String URL = System.getProperty("url", "ws://127.0.0.1:8080/websocket");
    public static final String SURL = System.getProperty("url", "ws://127.0.0.1:8843/websocket");

    public static void main(String[] args) 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 = uri.getPort();

        if (!"ws".equalsIgnoreCase(scheme) && !"wss".equalsIgnoreCase(scheme)) {
            System.out.println("只支持ws");
            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(WebSocketClientHandshakerFactory.newHandshaker(uri, WebSocketVersion.V13, null, true, new DefaultHttpHeaders()));

            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            ChannelPipeline p = socketChannel.pipeline();
                            if (sslCtx != null) {
                                p.addLast(sslCtx.newHandler(socketChannel.alloc(), host, port));
                            }
                            //http協議握手
                            p.addLast(new HttpClientCodec());
                            p.addLast(new HttpObjectAggregator(8192));
                            //支持websocket數據壓縮
                            p.addLast(WebSocketClientCompressionHandler.INSTANCE);
                            p.addLast(handler);
                        }
                    });
            //連接服務器
            Channel ch = b.connect(uri.getHost(), port).sync().channel();
            //等待握手完成
            handler.handshakeFuture().sync();

            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();
        }
    }

}

自定義handler

package com.gg.socket.client;

import io.netty.channel.*;
import io.netty.handler.codec.http.FullHttpResponse;
import io.netty.handler.codec.http.websocketx.*;
import io.netty.util.CharsetUtil;

/**
 * @Description WebSocketClientHandler
 * @Author honry.guan
 * @Date 2020/5/25 10:47
 */
public class WebSocketClientHandler extends SimpleChannelInboundHandler<Object> {
    /**
     * 負責和服務器握手
     */
    private final WebSocketClientHandshaker handshaker;
    /**
     * 握手結果
     */
    private ChannelPromise handshakeFuture;

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

    public ChannelFuture handshakeFuture() {
        return handshakeFuture;
    }


    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        handshaker.handshake(ctx.channel());
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("連接斷開");
    }

    /**
     * 當前handler被添加到pipeline時，new出握手的結果示例，以備將來使用
     *
     * @param ctx
     * @throws Exception
     */
    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        handshakeFuture = ctx.newPromise();
    }

    /**
     * 讀取數據
     *
     * @param ctx
     * @param msg
     * @throws Exception
     */
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        Channel ch = ctx.channel();
        //握手未完成，完成握手
        if (!handshaker.isHandshakeComplete()) {
            try {
                handshaker.finishHandshake(ch, (FullHttpResponse) msg);
                System.out.println("完成連接");
                handshakeFuture.setSuccess();
            } catch (WebSocketHandshakeException e) {
                System.out.println("握手連接失敗");
                handshakeFuture.setFailure(e);
            }
            return;
        }
        //握手完成，升級爲websocket，不應該再收到http報文
        if (msg instanceof FullHttpResponse) {
            FullHttpResponse response = (FullHttpResponse) msg;
            throw new IllegalStateException(
                    "Unexpected FullHttpResponse (getStatus=" + response.status() +
                            ", content=" + response.content().toString(CharsetUtil.UTF_8) + ')');
        }

        //處理websocket報文
        WebSocketFrame frame = (WebSocketFrame) msg;
        if (frame instanceof TextWebSocketFrame) {
            TextWebSocketFrame textWebSocketFrame = (TextWebSocketFrame) frame;
            System.out.println("收到消息：" + textWebSocketFrame.text());
        } else if (frame instanceof PongWebSocketFrame) {
            System.out.println("客戶端收到pong");
        } else if (frame instanceof CloseWebSocketFrame) {
            System.out.println("客戶端手動關閉");
            ch.close();
        }
    }

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

在窗口發送123

完成連接
你好
收到消息：客戶端收到單發消息：你好
收到消息：客戶端收到羣發消息：你好