java websocket netty_基于netty实现的websocket
一、运行效果
二、Netty使用场景
1.高性能领域
2.多线程并发领域
3.异步通信领域
三、实现过程
①、添加netty相关jar
io.netty
netty-all
5.0.0.Alpha1
②、添加netty配置类public class NettyConfig {
/**
* 存储每一个客户端接入进来时的channel对象
*/
public static ChannelGroup group = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
}
③、添加websocket核心业务处理类private WebSocketServerHandshaker handshaker;
private static final String WEB_SOCKET_URL = "ws://localhost:8888/websocket";
//客户端与服务端创建连接的时候调用
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
NettyConfig.group.add(ctx.channel());
System.out.println("客户端与服务端连接开启...");
}
//客户端与服务端断开连接的时候调用
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
NettyConfig.group.remove(ctx.channel());
System.out.println("客户端与服务端连接关闭...");
}
//服务端接收客户端发送过来的数据结束之后调用
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}
//工程出现异常的时候调用
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
//服务端处理客户端websocket请求的核心方法
@Override
protected void messageReceived(ChannelHandlerContext context, Object msg) throws Exception {
//处理客户端向服务端发起http握手请求的业务
if (msg instanceof FullHttpRequest) {
handHttpRequest(context, (FullHttpRequest)msg);
}else if (msg instanceof WebSocketFrame) { //处理websocket连接业务
handWebsocketFrame(context, (WebSocketFrame)msg);
}
}
/**
* 处理客户端与服务端之前的websocket业务
* @param ctx
* @param frame
*/
private void handWebsocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame){
//判断是否是关闭websocket的指令
if (frame instanceof CloseWebSocketFrame) {
handshaker.close(ctx.channel(), (CloseWebSocketFrame)frame.retain());
}
//判断是否是ping消息
if (frame instanceof PingWebSocketFrame) {
ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));
return;
}
//判断是否是二进制消息，如果是二进制消息，抛出异常
if( ! (frame instanceof TextWebSocketFrame) ){
System.out.println("目前我们不支持二进制消息");
throw new RuntimeException("【"+this.getClass().getName()+"】不支持消息");
}
//返回应答消息
//获取客户端向服务端发送的消息
String request = ((TextWebSocketFrame) frame).text();
System.out.println("服务端收到客户端的消息====>>>" + request);
TextWebSocketFrame tws = new TextWebSocketFrame(new Date().toString()
+ ctx.channel().id()
+ " ===>>> "
+ request);
//群发，服务端向每个连接上来的客户端群发消息
NettyConfig.group.writeAndFlush(tws);
}
④、websocket初始化时各个组件的类实现public class MyWebSocketChannelHandler extends ChannelInitializer {
@Override
protected void initChannel(SocketChannel e) throws Exception {
e.pipeline().addLast("http-codec", new HttpServerCodec());
e.pipeline().addLast("aggregator", new HttpObjectAggregator(65536));
e.pipeline().addLast("http-chunked", new ChunkedWriteHandler());
e.pipeline().addLast("handler", new MyWebSocketHandler());
}
}
四、项目结构图
五、补充
