之前寫了一篇文章：Java 網絡IO編程總結（BIO、NIO、AIO均含完整實例代碼），介紹了如何使用Java原生IO支持進行網絡編程，本文介紹一種更為簡單的方式，即Java NIO框架。
Netty是業界最流行的NIO框架之一，具有良好的健壯性、功能、性能、可定制性和可擴展性。同時，它提供的十分簡單的API，大大簡化了我們的網絡編程。
同Java IO介紹的文章一樣，本文所展示的例子，實現了一個相同的功能。
1、服務端
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("服務器開啟："+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("收到客戶端消息:"+body);
String calrResult = null;
try{
calrResult = Calculator.Instance.cal(body).toString();
}catch(Exception e){
calrResult = "錯誤的表達式：" + e.getMessage();
}
ctx.write(Unpooled.copiedBuffer(calrResult.getBytes()));
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}
/**
* 異常處理
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
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("收到客戶端消息:"+body);
String calrResult = null;
try{
calrResult = Calculator.Instance.cal(body).toString();
}catch(Exception e){
calrResult = "錯誤的表達式：" + e.getMessage();
}
ctx.write(Unpooled.copiedBuffer(calrResult.getBytes()));
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}
/**
* 異常處理
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
2、客戶端
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鏈路簡歷成功后調用
*/
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
this.ctx = ctx;
}
public boolean sendMsg(String msg){
System.out.println("客戶端發送消息："+msg);
byte[] req = msg.getBytes();
ByteBuf m = Unpooled.buffer(req.length);
m.writeBytes(req);
ctx.writeAndFlush(m);
return msg.equals("q")?false:true;
}
/**
* 收到服務器消息后調用
* @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("服務器消息："+body);
}
/**
* 發生異常時調用
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
3、用于計算的工具類
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、測試
分別啟動服務端和客戶端，然后再客戶端控制臺輸入表達式：
1+5+5+5+5+5 客戶端發送消息：1+5+5+5+5+5 服務器消息：26 156158*458918+125615 客戶端發送消息：156158*458918+125615 服務器消息：7.1663842659E10 1895612+555+5+5+5+5+5+5+5-5*4/4 客戶端發送消息：1895612+555+5+5+5+5+5+5+5-5*4/4 服務器消息：1896197
可以看到服務端返回的結果。
查看服務端控制臺：
服務器開啟：9090 收到客戶端消息:1+5+5+5+5+5 收到客戶端消息:156158*458918+125615 收到客戶端消息:1895612+555+5+5+5+5+5+5+5-5*4/4
5、更多
相關文章：
Java 網絡IO編程總結（BIO、NIO、AIO均含完整實例代碼）
本文例子以及Java BIO NIO AIO例子的源碼Git地址：https://github.com/anxpp/Java-IO.git
后續會繼續更新Netty相關內容，直到一個簡陋的通訊服務器完成。
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持億速云。
免責聲明：本站發布的內容（圖片、視頻和文字）以原創、轉載和分享為主，文章觀點不代表本網站立場，如果涉及侵權請聯系站長郵箱：is@yisu.com進行舉報，并提供相關證據，一經查實，將立刻刪除涉嫌侵權內容。
