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這篇文章將為大家詳細講解有關 Netty NIO 框架性能壓測之如何實現長鏈接，丸趣 TV 小編覺得挺實用的，因此分享給大家做個參考，希望大家閱讀完這篇文章后可以有所收獲。
壓測準備
需要將 ulimit -n 改大，否則 nio 鏈接開不大。
準備 4 臺機器 (1 臺 netty 服務器，3 臺壓測機)
使用 apache 的 ab 做壓測工具
開始干活
壓測代碼：
package org.dueam.sample.netty;
package org.dueam.sample.netty;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
import java.util.concurrent.Executors;
import org.jboss.netty.bootstrap.ServerBootstrap;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.DynamicChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelFactory;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelHandler;
import org.jboss.netty.channel.ChannelHandler.Sharable;
import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;
public class ChatServer {
public static void main(String[] args) throws Exception {if(args.length 1){args = new String[]{ 9876 , true
ChannelFactory factory = new NioServerSocketChannelFactory(Executors
.newCachedThreadPool(), Executors.newCachedThreadPool());
ServerBootstrap bootstrap = new ServerBootstrap(factory);
ChatServerHandler handler = new ChatServerHandler();
ChannelPipeline pipeline = bootstrap.getPipeline();
pipeline.addLast(chat , handler);
bootstrap.setOption(child.tcpNoDelay , true);
bootstrap.setOption(child.keepAlive , true);
int port = Integer.valueOf(args[0]);
bootstrap.bind(new InetSocketAddress(port));
boolean fillChat = true .equals(args[1]);
if (fillChat) {ChannelManagerThread cmt = new ChannelManagerThread();
cmt.start();
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
while (true) {String command = br.readLine();
if (dump .equals(command)) {System.out.println( 當前活著的數量: + channel.size());
} else if (help .equals(command)) {
System.out.println( 命令列表:
System.out.println( dump: 打印當前情況
System.out.println( help: 幫助文檔
final static Random random = new Random();
static int max = 0;
static class ChannelManagerThread extends Thread {
@Override
public void run() {while (true) {
try {if(max channel.size()){max = channel.size() ;
System.out.println(live: +channel.size());
for (Channel s : channel.values()) {if (random.nextInt(100) 70) {ChannelBuffer cb = new DynamicChannelBuffer(256);
cb.writeBytes(Hey! 有人來找你了! .getBytes());
s.write(cb);
sleep(500);
} catch (InterruptedException e) {
final static Map Integer, Channel channel = new HashMap Integer, Channel
static void log(String message) {System.out.println(message);
@Sharable
static class ChatServerHandler extends SimpleChannelHandler {
@Override
public void channelConnected(ChannelHandlerContext ctx,
ChannelStateEvent e) {Channel ch = e.getChannel();
ChannelBuffer cb = new DynamicChannelBuffer(256);
cb.writeBytes(Hell! 你來了啊! .getBytes());
ch.write(cb);
channel.put(e.getChannel().getId(), e.getChannel());
@Override
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) {
@Override
public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) {e.getCause().printStackTrace();
channel.remove(e.getChannel().getId());
log(remove channel by exception! id: + e.getChannel().getId());
e.getChannel().close();
@Override
public void channelDisconnected(ChannelHandlerContext ctx,
ChannelStateEvent e) throws Exception {channel.remove(e.getChannel().getId());
log(remove channel by exception! id: + e.getChannel().getId());
}壓測方式：
# 加大超時和并發量，并使用 keep-alive 的方式保持住端口
./ab -n 20000 -c 20000 -k -t 999999999 -r http://192.168.216.30:9876/壓測結果
內存損耗：
[root@cap216030 ~]# free -k -t -s 10
-- 原始內存
total used free shared buffers cached
Mem: 4149076 189828 3959248 0 13196 95484
-/+ buffers/cache: 81148 4067928
Swap: 2096472 208 2096264
Total: 6245548 190036 6055512
-- 執行 chat server 之后
total used free shared buffers cached
Mem: 4149076 207236 3941840 0 13216 96244
-/+ buffers/cache: 97776 4051300
Swap: 2096472 208 2096264
Total: 6245548 207444 6038104
-- 59471 個 nio 連接之后
total used free shared buffers cached
Mem: 4149076 474244 3674832 0 13328 96132
-/+ buffers/cache: 364784 3784292
Swap: 2096472 208 2096264
Total: 6245548 474452 5771096結論：
Netty nio 可以輕松將鏈接開到 6W，每個線程大概損壞 5k 左右的系統內存
后續壓測方案
編寫 Java 客戶端做內容實時雙向推送
使用 100 臺機器每臺機器起 1000 個線程來模擬客戶端進行壓測
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正文完
