转载Java NIO框架Netty简单使用 (http://blog.csdn.net/anxpp)
转载请注明出处:http://blog.csdn.net/anxpp/article/details/52108238,谢谢!
之前写了一篇文章:Java 网络IO编程总结(BIO、NIO、AIO均含完整实例代码),介绍了如何使用Java原生IO支持进行网络编程,本文介绍一种更为简单的方式,即Java NIO框架。
Netty是业界最流行的NIO框架之一,具有良好的健壮性、功能、性能、可定制性和可扩展性。同时,它提供的十分简单的API,大大简化了我们的网络编程。
同Java IO介绍的文章一样,本文所展示的例子,实现了一个相同的功能。
1、服务端
Server:
- package com.anxpp.io.calculator.netty;
- import io.netty.bootstrap.ServerBootstrap;
- import io.netty.channel.ChannelFuture;
- import io.netty.channel.ChannelInitializer;
- import io.netty.channel.ChannelOption;
- import io.netty.channel.EventLoopGroup;
- import io.netty.channel.nio.NioEventLoopGroup;
- import io.netty.channel.socket.SocketChannel;
- import io.netty.channel.socket.nio.NioServerSocketChannel;
- public class Server {
- private int port;
- public Server(int port) {
- this.port = port;
- }
- public void run() throws Exception {
- EventLoopGroup bossGroup = new NioEventLoopGroup();
- EventLoopGroup workerGroup = new NioEventLoopGroup();
- try {
- ServerBootstrap b = new ServerBootstrap();
- b.group(bossGroup, workerGroup)
- .channel(NioServerSocketChannel.class)
- .option(ChannelOption.SO_BACKLOG, 1024)
- .childOption(ChannelOption.SO_KEEPALIVE, true)
- .childHandler(new ChannelInitializer<SocketChannel>() {
- @Override
- public void initChannel(SocketChannel ch) throws Exception {
- ch.pipeline().addLast(new ServerHandler());
- }
- });
- ChannelFuture f = b.bind(port).sync();
- System.out.println("服务器开启:"+port);
- f.channel().closeFuture().sync();
- } finally {
- workerGroup.shutdownGracefully();
- bossGroup.shutdownGracefully();
- }
- }
- public static void main(String[] args) throws Exception {
- int port;
- if (args.length > 0) {
- port = Integer.parseInt(args[0]);
- } else {
- port = 9090;
- }
- new Server(port).run();
- }
- }
ServerHandler:
- package com.anxpp.io.calculator.netty;
- import io.netty.buffer.ByteBuf;
- import io.netty.buffer.Unpooled;
- import io.netty.channel.ChannelHandlerContext;
- import io.netty.channel.ChannelInboundHandlerAdapter;
- import java.io.UnsupportedEncodingException;
- import com.anxpp.io.utils.Calculator;
- public class ServerHandler extends ChannelInboundHandlerAdapter {
- @Override
- public void channelRead(ChannelHandlerContext ctx, Object msg) throws UnsupportedEncodingException {
- ByteBuf in = (ByteBuf) msg;
- byte[] req = new byte[in.readableBytes()];
- in.readBytes(req);
- String body = new String(req,"utf-8");
- System.out.println("收到客户端消息:"+body);
- String calrResult = null;
- try{
- calrResult = Calculator.Instance.cal(body).toString();
- }catch(Exception e){
- calrResult = "错误的表达式:" + e.getMessage();
- }
- ctx.write(Unpooled.copiedBuffer(calrResult.getBytes()));
- }
- @Override
- public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
- ctx.flush();
- }
- /**
- * 异常处理
- */
- @Override
- public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
- cause.printStackTrace();
- ctx.close();
- }
- }
2、客户端
Client:
- package com.anxpp.io.calculator.netty;
- import io.netty.bootstrap.Bootstrap;
- import io.netty.channel.ChannelFuture;
- import io.netty.channel.ChannelInitializer;
- import io.netty.channel.ChannelOption;
- import io.netty.channel.EventLoopGroup;
- import io.netty.channel.nio.NioEventLoopGroup;
- import io.netty.channel.socket.SocketChannel;
- import io.netty.channel.socket.nio.NioSocketChannel;
- import java.util.Scanner;
- public class Client implements Runnable{
- static ClientHandler client = new ClientHandler();
- public static void main(String[] args) throws Exception {
- new Thread(new Client()).start();
- @SuppressWarnings("resource")
- Scanner scanner = new Scanner(System.in);
- while(client.sendMsg(scanner.nextLine()));
- }
- @Override
- public void run() {
- String host = "127.0.0.1";
- int port = 9090;
- EventLoopGroup workerGroup = new NioEventLoopGroup();
- try {
- Bootstrap b = new Bootstrap();
- b.group(workerGroup);
- b.channel(NioSocketChannel.class);
- b.option(ChannelOption.SO_KEEPALIVE, true);
- b.handler(new ChannelInitializer<SocketChannel>() {
- @Override
- public void initChannel(SocketChannel ch) throws Exception {
- ch.pipeline().addLast(client);
- }
- });
- ChannelFuture f = b.connect(host, port).sync();
- f.channel().closeFuture().sync();
- } catch (InterruptedException e) {
- e.printStackTrace();
- } finally {
- workerGroup.shutdownGracefully();
- }
- }
- }
ClientHandler:
- package com.anxpp.io.calculator.netty;
- import io.netty.buffer.ByteBuf;
- import io.netty.buffer.Unpooled;
- import io.netty.channel.ChannelHandlerContext;
- import io.netty.channel.ChannelInboundHandlerAdapter;
- import java.io.UnsupportedEncodingException;
- public class ClientHandler extends ChannelInboundHandlerAdapter {
- ChannelHandlerContext ctx;
- /**
- * tcp链路简历成功后调用
- */
- @Override
- public void channelActive(ChannelHandlerContext ctx) throws Exception {
- this.ctx = ctx;
- }
- public boolean sendMsg(String msg){
- System.out.println("客户端发送消息:"+msg);
- byte[] req = msg.getBytes();
- ByteBuf m = Unpooled.buffer(req.length);
- m.writeBytes(req);
- ctx.writeAndFlush(m);
- return msg.equals("q")?false:true;
- }
- /**
- * 收到服务器消息后调用
- * @throws UnsupportedEncodingException
- */
- @Override
- public void channelRead(ChannelHandlerContext ctx, Object msg) throws UnsupportedEncodingException {
- ByteBuf buf = (ByteBuf) msg;
- byte[] req = new byte[buf.readableBytes()];
- buf.readBytes(req);
- String body = new String(req,"utf-8");
- System.out.println("服务器消息:"+body);
- }
- /**
- * 发生异常时调用
- */
- @Override
- public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
- cause.printStackTrace();
- ctx.close();
- }
- }
3、用于计算的工具类
- package com.anxpp.io.utils;
- import javax.script.ScriptEngine;
- import javax.script.ScriptEngineManager;
- import javax.script.ScriptException;
- public enum Calculator {
- Instance;
- private final static ScriptEngine jse = new ScriptEngineManager().getEngineByName("JavaScript");
- public Object cal(String expression) throws ScriptException{
- return jse.eval(expression);
- }
- }
4、测试
分别启动服务端和客户端,然后再客户端控制台输入表达式:
- 1+5+5+5+5+5
- 客户端发送消息:1+5+5+5+5+5
- 服务器消息:26
- 156158*458918+125615
- 客户端发送消息:156158*458918+125615
- 服务器消息:7.1663842659E10
- 1895612+555+5+5+5+5+5+5+5-5*4/4
- 客户端发送消息:1895612+555+5+5+5+5+5+5+5-5*4/4
- 服务器消息:1896197
可以看到服务端返回的结果。
查看服务端控制台:
- 服务器开启:9090
- 收到客户端消息:1+5+5+5+5+5
- 收到客户端消息:156158*458918+125615
- 收到客户端消息:1895612+555+5+5+5+5+5+5+5-5*4/4