netty4学习笔记5-netty作为WebSocket服务器

需求:

编写一个WebSocket服务器，来完成读取客户端的请求，并完成相应

编写步骤:

1. 编写服务器端的启动程序

package com.baidu.netty.fouthExample;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;

public class MyServer {
    public static void main(String[] args) throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(bossGroup,workerGroup).channel(NioServerSocketChannel.class).childHandler(new MyServerInitializer());
            ChannelFuture future = bootstrap.bind(8899).sync();
            future.channel().closeFuture().sync();
        }finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }

}

2. 编写服务器端的初始化程序

package com.baidu.netty.fouthExample;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
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.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.handler.stream.ChunkedWriteHandler;
import io.netty.util.CharsetUtil;

public class MyServerInitializer extends ChannelInitializer {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        pipeline.addLast(new HttpServerCodec());
        /**以块的形式写*/
        pipeline.addLast(new ChunkedWriteHandler());
        /**将块组装成对象（比如该处用到的文本对象）*/
        pipeline.addLast(new HttpObjectAggregator(1024));
        /**添加对于websocket的支持,参数配置的是访问的路径*/
        pipeline.addLast(new WebSocketServerProtocolHandler("/ws"));
        pipeline.addLast(new MyServerHandler());
    }
}

3. 编写服务器的处理程序

package com.baidu.netty.fouthExample;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;

public class MyServerHandler extends SimpleChannelInboundHandler {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
        System.out.println("【客户端的消息】:" + msg.text());
        /**返回的时候也必须要是TextWebSocketFrame对象而不能是普通的字符串*/
        TextWebSocketFrame content = new TextWebSocketFrame("你好客户端");
        ctx.writeAndFlush(content);
    }

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

4. 编写html5的socket请求程序