1.什么是Echo服务和快速创建Netty项目
1)什么是Echo服务：就是一个应答服务（回显服务器），客户端发送什么数据，服务端就响应的对应的数据
是一个非常有的用于调试和检测的服务(压测、检查服务是否存活)
（client端也可以进行Handler处理）
2)IDEA + Maven + jdk8
netty依赖包 ( 查找方式netty maven)
3) maven地址：https://mvnrepository.com/artifact/io.netty/netty-all/4.1.32.Final
2.Echo服务-服务端程序编写
1)创建maven项目引入maven的依赖
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.32.Final</version>
</dependency>2）创建server
public class EchoServer {
//创建构造方法
private int port;
public EchoServer(int port){
this.port=port;
}
public static void main(String[] args) throws InterruptedException {
//如果之前有端口号用原理的
int port=8080;
if (args.length>0){
port=Integer.getInteger(args[0]);
}
new EchoServer(port).run();
}
/**
*
* 功能描述: 启动方法前台多个服务 处理多个线程
*
* @param:
* @return:
* @auther: LiGang
* @date: 2019/3/26 11:31
*/
/**
* 启动流程
*/
private void run() throws InterruptedException {
//配置服务端线程组
EventLoopGroup bossGroup=new NioEventLoopGroup();
EventLoopGroup workGroup=new NioEventLoopGroup();
try{
//引导整个server的启动
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup,workGroup)
.channel(NioServerSocketChannel.class) //指定处理的连接类型
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(new EchoServerHandler());
}
});
System.out.println("Echo 服务器启动ing");
//绑定端口，同步等待成功
ChannelFuture cf = serverBootstrap.bind(port).sync();
System.out.println("ok");
// 等待服务端监听端口关闭
cf.channel().closeFuture().sync();
}finally {
//优雅的退出
bossGroup.shutdownGracefully();
workGroup.shutdownGracefully();
}
}
}
3）创建handler
public class EchoServerHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
ByteBuf data = (ByteBuf) msg;
System.out.println("收到的信息为："+data.toString(CharsetUtil.UTF_8));
// ctx.writeAndFlush(msg);
ctx.write(msg);
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.writeAndFlush("111");
System.out.println("EchoServerHandle channelReadComplete");
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
3.Echo服务-客户端程序编写
public class EchoClient {
private String host;
private int port;
public EchoClient(String host,int port){
this.port=port;
this.host=host;
}
public static void main(String[] args) throws InterruptedException {
new EchoClient("127.0.0.1",8080).start();
}
private void start() throws InterruptedException {
EventLoopGroup loopGroup = new NioEventLoopGroup();
try{
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(loopGroup)
.channel(NioSocketChannel.class)
.remoteAddress(new InetSocketAddress(host, port))
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(new EchoClientHandler());
}
});
//连接到服务端，connect是异步连接，调用sync同步等待连接成功
ChannelFuture channelFuture = bootstrap.connect().sync();
//阻塞直到客户端通道关闭
channelFuture.channel().closeFuture().sync();
}finally {
loopGroup.shutdownGracefully();
}
}
}
handler
public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {
@Override
protected void channelRead0(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf) throws Exception {
System.out.println("EchoClient :receive"+byteBuf.toString(CharsetUtil.UTF_8));
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.writeAndFlush("read complete");
System.out.println("client read ok");
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println("client is sign in ");
ctx.writeAndFlush(Unpooled.copiedBuffer("哈哈",CharsetUtil.UTF_8));
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}