以下两个例子基于netty-3.5.7.Final.jar用Junit进行测试
第一个例子：简单的发送字符串，接收字符串“Hello, World”
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class HelloWorldServerHandler extends SimpleChannelHandler { public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { e.getChannel().write("Hello, World"); } public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) { System.out.println("Unexpected exception from downstream." + e.getCause()); e.getChannel().close(); } } class HelloWorldClientHandler extends SimpleChannelHandler { public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) { String message = (String) e.getMessage(); System.out.println(message); e.getChannel().close(); } public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) { System.out.println("Unexpected exception from downstream." + e.getCause()); e.getChannel().close(); } } /** * Netty VS MinaNetty基于Pipeline处理，Mina基于Filter过滤 * Netty的事件驱动模型具有更好的扩展性和易用性 * Https，SSL，PB，RSTP，Text &Binary等协议支持 * Netty中UDP传输有更好的支持官方测试Netty比Mina性能更好 * @author Administrator * */ public class TestCase { public void testServer() { //初始化channel的辅助类，为具体子类提供公共数据结构 ServerBootstrap bootstrap = new ServerBootstrap( new NioServerSocketChannelFactory( Executors.newCachedThreadPool(), Executors.newCachedThreadPool())); bootstrap.setPipelineFactory(new ChannelPipelineFactory() { public ChannelPipeline getPipeline() { ChannelPipeline pipeline = Channels.pipeline(); pipeline.addLast("decoder", new StringDecoder()); pipeline.addLast("encoder", new StringEncoder()); pipeline.addLast("handler", new HelloWorldServerHandler()); return pipeline; } }); //创建服务器端channel的辅助类,接收connection请求 bootstrap.bind(new InetSocketAddress(8080)); } public void testClient() { //创建客户端channel的辅助类,发起connection请求 ClientBootstrap bootstrap = new ClientBootstrap( new NioClientSocketChannelFactory( Executors.newCachedThreadPool(), Executors.newCachedThreadPool())); //It means one same HelloWorldClientHandler instance is going to handle multiple Channels and consequently the data will be corrupted. //基于上面这个描述，必须用到ChannelPipelineFactory每次创建一个pipeline bootstrap.setPipelineFactory(new ChannelPipelineFactory() { public ChannelPipeline getPipeline() { ChannelPipeline pipeline = Channels.pipeline(); pipeline.addLast("decoder", new StringDecoder()); pipeline.addLast("encoder", new StringEncoder()); pipeline.addLast("handler", new HelloWorldClientHandler()); return pipeline; } }); //创建无连接传输channel的辅助类(UDP),包括client和server ChannelFuture future = bootstrap.connect(new InetSocketAddress( "localhost", 8080)); future.getChannel().getCloseFuture().awaitUninterruptibly(); bootstrap.releaseExternalResources(); } @Test public void testNetty(){ testServer(); testClient(); } } |
第二个例子，实际应用中会用到这个，发送POJO类Persons [name=周杰伦123, age=31, salary=10000.44]
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/** * 用POJO代替ChannelBuffer */ class TimeServerHandler3 extends SimpleChannelHandler { @Override public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { Persons person = new Persons("周杰伦123",31,10000.44); ChannelFuture future = e.getChannel().write(person); future.addListener(ChannelFutureListener.CLOSE); } } class TimeClientHandler3 extends SimpleChannelHandler{ @Override public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception { Persons person = (Persons)e.getMessage(); System.out.println(person); e.getChannel().close(); } } /** * FrameDecoder and ReplayingDecoder allow you to return an object of any type. * */ class TimeDecoder extends FrameDecoder { private final ChannelBuffer buffer = dynamicBuffer(); @Override protected Object decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer channelBuffer) throws Exception { if(channelBuffer.readableBytes()<4) { return null; } if (channelBuffer.readable()) { // 读到,并写入buf channelBuffer.readBytes(buffer, channelBuffer.readableBytes()); } int namelength = buffer.readInt(); String name = new String(buffer.readBytes(namelength).array(),"GBK"); int age = buffer.readInt(); double salary = buffer.readDouble(); Persons person = new Persons(name,age,salary); return person; } } class TimeEncoder extends SimpleChannelHandler { private final ChannelBuffer buffer = dynamicBuffer(); @Override public void writeRequested(ChannelHandlerContext ctx, MessageEvent e) throws Exception { Persons person = (Persons)e.getMessage(); buffer.writeInt(person.getName().getBytes("GBK").length); buffer.writeBytes(person.getName().getBytes("GBK")); buffer.writeInt(person.getAge()); buffer.writeDouble(person.getSalary()); Channels.write(ctx, e.getFuture(), buffer); } } class Persons{ private String name; private int age; private double salary; public Persons(String name,int age,double salary){ this.name = name; this.age = age; this.salary = salary; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public double getSalary() { return salary; } public void setSalary(double salary) { this.salary = salary; } @Override public String toString() { return "Persons [name=" + name + ", age=" + age + ", salary=" + salary + "]"; } } public class TestCase5 { public void testServer() { ChannelFactory factory = new NioServerSocketChannelFactory(Executors.newCachedThreadPool(), Executors.newCachedThreadPool()); ServerBootstrap bootstrap = new ServerBootstrap(factory); bootstrap.setPipelineFactory(new ChannelPipelineFactory() { public ChannelPipeline getPipeline() throws Exception { return Channels.pipeline(new TimeEncoder(), new TimeServerHandler3()); } }); bootstrap.setOption("child.tcpNoDelay", true); bootstrap.setOption("child.keepAlive", true); bootstrap.bind(new InetSocketAddress("localhost",9999)); } public void testClient(){ //创建客户端channel的辅助类,发起connection请求 ClientBootstrap bootstrap = new ClientBootstrap( new NioClientSocketChannelFactory( Executors.newCachedThreadPool(), Executors.newCachedThreadPool())); bootstrap.setPipelineFactory(new ChannelPipelineFactory() { public ChannelPipeline getPipeline() { ChannelPipeline pipeline = Channels.pipeline(); pipeline.addLast("decoder", new TimeDecoder()); pipeline.addLast("encoder", new TimeEncoder()); pipeline.addLast("handler", new TimeClientHandler3()); return pipeline; } }); //创建无连接传输channel的辅助类(UDP),包括client和server ChannelFuture future = bootstrap.connect(new InetSocketAddress( "localhost", 9999)); future.getChannel().getCloseFuture().awaitUninterruptibly(); bootstrap.releaseExternalResources(); } @Test public void testNetty() { testServer(); testClient(); } } |
这两段代码是学习的时候参考别人的代码，转于哪想不起来了，但是这两段代码让我了解了netty的通信流程。
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