Netty(1):第一个netty程序

 1 package com.rampage.netty.time;
 2 
 3 import io.netty.bootstrap.ServerBootstrap;
 4 import io.netty.channel.ChannelFuture;
 5 import io.netty.channel.ChannelInitializer;
 6 import io.netty.channel.ChannelOption;
 7 import io.netty.channel.EventLoopGroup;
 8 import io.netty.channel.nio.NioEventLoopGroup;
 9 import io.netty.channel.socket.SocketChannel;
10 import io.netty.channel.socket.nio.NioServerSocketChannel;
11 
12 /**
13  * 时钟程序的服务器端
14  * @author zyq
15  *
16  */
17 public class TimeServer {
18     
19     public static void main(String[] args) throws Exception {
20         new TimeServer().bind(8080);
21     }
22     
23     public void bind(int port) throws Exception {
24         // 配置服务器的NIO线程组
25         EventLoopGroup bossGroup = new NioEventLoopGroup();
26         EventLoopGroup workerGroup = new NioEventLoopGroup();
27         
28         try {
29             ServerBootstrap bootStrap = new ServerBootstrap();
30             
31             // 进行链式调用（每一次调用的返回结果都是ServerBootstrap）
32             // group带两个参数第一个表示给父（acceptor）用的EventExecutorGroup（其实就是线程池）
33             // 第二个参数表示子（client）线程池
34             // channel方法可以带一个ServerChannel类来创建进行IO操作的通道。
35             // option方法给Channel定制对应的选项
36             // childHandler方法用来处理Channel中的请求
37             bootStrap.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
38             .option(ChannelOption.SO_BACKLOG, 1024).childHandler(new ChildChannelHandler());
39             
40             // 绑定端口，等待同步成功
41             // bind方法返回一个ChannelFuture类，就是相当于绑定端口并且创建一个新的channel
42             // sync方法会等待ChannelFuture的处理结束
43             ChannelFuture future = bootStrap.bind(port).sync();
44             
45             // 等待服务器监听端口关闭
46             future.channel().closeFuture().sync();
47         } finally {
48             // 优雅地退出，释放线程资源
49             bossGroup.shutdownGracefully();
50             workerGroup.shutdownGracefully();
51         }
52     }
53     
54     private class ChildChannelHandler extends ChannelInitializer<SocketChannel> {
55 
56         @Override
57         protected void initChannel(SocketChannel arg0) throws Exception {
58             arg0.pipeline().addLast(new TimeServerHandler());
59         }
60         
61     }
62 }

 1 package com.rampage.netty.time;
 2 
 3 import java.util.Date;
 4 
 5 import io.netty.buffer.ByteBuf;
 6 import io.netty.buffer.Unpooled;
 7 import io.netty.channel.ChannelHandlerAdapter;
 8 import io.netty.channel.ChannelHandlerContext;
 9 
10 /**
11  * 时间服务器的处理类，只有netty5中的ChannelHandlerAdapter中才有ChannelRead和ChannelReadComplete方法。
12  * @author zyq
13  *
14  */
15 public class TimeServerHandler extends ChannelHandlerAdapter {
16     @Override 
17     public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
18         // netty中的ByteBuf类相当于jdk中的ByteBuffer类，但是功能更加强大
19         ByteBuf buf = (ByteBuf) msg;
20         
21         // readableBytes返回缓冲区可读的字节数
22         byte[] req = new byte[buf.readableBytes()];
23         
24         // 将缓冲区的字节数复制到新的字节数组中去
25         buf.readBytes(req);
26         
27         // 根据客户端传来的信息得到应答信息
28         String body = new String(req, "UTF-8");
29         System.out.println("The time server receive order:" + body);
30         String currentTime = "QUERY TIME ORDER".equalsIgnoreCase(body) ? new Date(System.currentTimeMillis()).toString() : "BAD ORDER";
31         
32         // 给客户端的回应
33         ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
34         
35         // 为了防止频繁唤醒Selector进行消息发送，Netty的write方法并不直接将消息写入到SocketChannel中，而是把消息放入到缓冲数组
36         ctx.write(resp);
37     }
38 
39     @Override
40     public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
41         // 将放到缓冲数组中的消息写入到SocketChannel中去
42         ctx.flush();
43     }
44 
45     @Override
46     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
47         ctx.close();
48     }
49     
50     
51 }

 1 package com.rampage.netty.time;
 2 
 3 import io.netty.bootstrap.Bootstrap;
 4 import io.netty.channel.ChannelFuture;
 5 import io.netty.channel.ChannelInitializer;
 6 import io.netty.channel.ChannelOption;
 7 import io.netty.channel.EventLoopGroup;
 8 import io.netty.channel.nio.NioEventLoopGroup;
 9 import io.netty.channel.socket.SocketChannel;
10 import io.netty.channel.socket.nio.NioSocketChannel;
11 
12 /**
13  * 时钟程序的客户端
14  * @author zyq
15  *
16  */
17 public class TimeClient {
18     
19     public static void main(String[] args) throws Exception {
20         new TimeClient().connect("127.0.0.1", 8080);
21     }
22     
23     public void connect(String host, int port) throws Exception {
24         // 配置客户端NIO线程池
25         EventLoopGroup group = new NioEventLoopGroup();
26         
27         Bootstrap strap = new Bootstrap();
28         try {
29             // 这里用了匿名内部类，各个函数的含义同Server端
30             strap.group(group).channel(NioSocketChannel.class).option(ChannelOption.TCP_NODELAY, true)
31             .handler(new ChannelInitializer<SocketChannel>() {
32 
33                 @Override
34                 protected void initChannel(SocketChannel arg0) throws Exception {
35                     arg0.pipeline().addLast(new TimeClientHandler());
36                 }
37                 
38             });
39             
40             // 发起异步连接操作
41             ChannelFuture future = strap.connect(host, port).sync();
42             
43             // 等待客户端关闭(注意调用的是closeFuture如果直接调用close会立马关闭)
44             future.channel().closeFuture().sync();
45         } finally {
46             // 优雅的关闭
47             group.shutdownGracefully();
48         }
49     }
50 }

 1 package com.rampage.netty.time;
 2 
 3 import java.util.logging.Logger;
 4 
 5 import io.netty.buffer.ByteBuf;
 6 import io.netty.buffer.Unpooled;
 7 import io.netty.channel.ChannelHandlerAdapter;
 8 import io.netty.channel.ChannelHandlerContext;
 9 
10 public class TimeClientHandler extends ChannelHandlerAdapter {
11 
12     private static final Logger LOGGER = Logger.getLogger(TimeClientHandler.class.getName());
13     
14     private final ByteBuf firstMsg;
15     
16     public TimeClientHandler() {
17         byte[] req = "QUERY TIME ORDER".getBytes();
18         firstMsg = Unpooled.buffer(req.length);
19         firstMsg.writeBytes(req);
20     }
21     
22     /**
23      * channel连通之后的处理
24      */
25     @Override
26     public void channelActive(ChannelHandlerContext ctx) throws Exception {
27         ctx.writeAndFlush(firstMsg);
28     }
29     
30     @Override
31     public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
32         ByteBuf buf = (ByteBuf) msg;
33         byte[] resp = new byte[buf.readableBytes()];
34         buf.readBytes(resp);
35         
36         String body = new String(resp, "UTF-8");
37         System.out.println("Now is:" + body);
38         
39         // 两秒钟后继续向服务器端发送消息
40         Thread.sleep(2000);
41         byte[] req = "QUERY TIME ORDER".getBytes();
42         ByteBuf sendMsg = Unpooled.buffer(req.length);
43         sendMsg.writeBytes(req);
44         ctx.writeAndFlush(sendMsg);
45     }
46 
47     @Override
48     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
49         LOGGER.warning("Unexpected exception from downstream:" + cause.getMessage());
50         ctx.close();
51     }
52 
53     
54 }