Grizzly开发Echoserver实战
作者：chszs，转载需注明。
博客主页：http://blog.csdn.net/chszs
用Java编写可伸缩的server应用是有难度的。用Java NIO开发、线程管理、为成千上万的用户做server扩展。这些都是难点。Grizzly NIO框架的设计目标就是帮助开发人员非常好地利用Java NIO API。编写出高可扩展性的、功能强大的server，并提高了扩展的框架组件：Web Framework（HTTP/S）、WebSocket、Comet等。
Grizzly 2.3开发Echoserver/client的样例
1、下载grizzly-framework.jar库
Maven依赖
<dependency><groupId>org.glassfish.grizzly</groupId><artifactId>grizzly-framework</artifactId><version>2.3.16</version>
</dependency>或下载地址： http://central.maven.org/maven2/org/glassfish/grizzly/grizzly-framework/2.3.16/grizzly-framework-2.3.16.jar
2014.10.23日刚公布了2.3.17版，地址见：
https://maven.java.net/content/repositories/releases/org/glassfish/grizzly/grizzly-framework/2.3.17/grizzly-framework-2.3.17.jar
也能够用这个版本号。
server端：
1）创建Echo过滤器
Echo过滤器负责把接收到的消息（无论其类型）原样返回给Grizzly连接。
import java.io.IOException;import org.glassfish.grizzly.filterchain.BaseFilter;
import org.glassfish.grizzly.filterchain.FilterChainContext;
import org.glassfish.grizzly.filterchain.NextAction;public class EchoFilter extends BaseFilter{/*** 仅处理读操作，当消息到来时进行处理* @param ctx 处理的上下文* @return 下一个动作*/@Overridepublic NextAction handleRead(FilterChainContext ctx) throws IOException{// Peer address用于无连接的UDP连接final Object peerAddress = ctx.getAddress();final Object message = ctx.getMessage();System.out.println("Server received: " + message);ctx.write(peerAddress, message, null);return ctx.getStopAction();}
}2）server初始化代码
全部的server过滤器链都准备好，開始初始化并启动server。
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.logging.Logger;import org.glassfish.grizzly.filterchain.FilterChainBuilder;
import org.glassfish.grizzly.filterchain.TransportFilter;
import org.glassfish.grizzly.nio.transport.TCPNIOTransport;
import org.glassfish.grizzly.nio.transport.TCPNIOTransportBuilder;
import org.glassfish.grizzly.utils.StringFilter;public class EchoServer {private static final Logger logger = Logger.getLogger(EchoServer.class.getName());public static final String HOST = "localhost";public static final int PORT = 7777;public static void main(String[] args) throws IOException{// 用FilterChainBuilder创建过滤器链FilterChainBuilder filterChainBuilder = FilterChainBuilder.stateless();// 加入TransportFilter。它负责从连接中读数据，并写数据到连接filterChainBuilder.add(new TransportFilter());// 字符串过滤器StringFilter负责缓冲和字符串之间的转换filterChainBuilder.add(new StringFilter(Charset.forName("UTF-8")));// 过滤器EchoFilter负责把接收到的消息原样返回给连接filterChainBuilder.add(new EchoFilter());// 创建TCP传输final TCPNIOTransport transport = TCPNIOTransportBuilder.newInstance().build();transport.setProcessor(filterChainBuilder.build());try{// 绑定传输，開始对主机+端口进行监听transport.bind(HOST, PORT);// 開始传输transport.start();logger.info("Press any key to stop the Echo server...");System.in.read();} finally{logger.info("Stopping transport...");// 停止传输servertransport.shutdown();logger.info("Stopped transport...");}}
}执行Echoserver：
java -classpath grizzly-framework.jar EchoServerclient：
1）创建client过滤器
client过滤器负责重定向server的响应到标准输出。
要注意，client过滤器须要FilterChainContext消息
import java.io.IOException;import org.glassfish.grizzly.filterchain.BaseFilter;
import org.glassfish.grizzly.filterchain.FilterChainContext;
import org.glassfish.grizzly.filterchain.NextAction;public class ClientFilter extends BaseFilter{/*** 仅处理读操作。当消息到来时进行处理* @param ctx 处理的上下文* @return 下一个动作*/@Overridepublic NextAction handleRead(final FilterChainContext ctx) throws IOException{// 从上下文得到字符串消息，过滤器链仅仅使用了字符串过滤器StringFilterfinal String serverResponse = ctx.getMessage();System.out.println("Server echo: " + serverResponse);return ctx.getStopAction();}
}2）client代码
简单的client，向Echoserver发送消息并等待响应。
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.logging.Logger;import org.glassfish.grizzly.Connection;
import org.glassfish.grizzly.Grizzly;
import org.glassfish.grizzly.filterchain.FilterChainBuilder;
import org.glassfish.grizzly.filterchain.TransportFilter;
import org.glassfish.grizzly.nio.transport.TCPNIOTransport;
import org.glassfish.grizzly.nio.transport.TCPNIOTransportBuilder;
import org.glassfish.grizzly.utils.StringFilter;import ch.echo.server.EchoServer;public class EchoClient {private static final Logger logger = Grizzly.logger(EchoClient.class);public static void main(String[] args) throws IOException,ExecutionException, InterruptedException, TimeoutException{Connection connection = null;// 用FilterChainBuilder类创建过滤器链FilterChainBuilder filterChainBuilder = FilterChainBuilder.stateless();// 加入传输过滤器，它负责从连接读数据并向连接写数据filterChainBuilder.add(new TransportFilter());// 加入字符串过滤器，它负责缓冲和字符串之间的转换filterChainBuilder.add(new StringFilter(Charset.forName("UTF-8")));// 加入client过滤器，他负责把server响应重定向到标准输出filterChainBuilder.add(new ClientFilter());// 创建TCP传输final TCPNIOTransport transport = TCPNIOTransportBuilder.newInstance().build();transport.setProcessor(filterChainBuilder.build());try{// 启动传输transport.start();// 异步执行。连接到serverFuture<Connection> future = transport.connect(EchoServer.HOST, EchoServer.PORT);// 等待连接操作的完毕connection = future.get(10, TimeUnit.SECONDS);assert connection!=null;System.out.println("Ready...(\"q\" to exit");final BufferedReader inReader = new BufferedReader(new InputStreamReader(System.in));do{final String userInput = inReader.readLine();if(userInput==null || "q".equals(userInput))break;connection.write(userInput);} while(true);} finally{// 关闭client连接if(connection!=null)connection.close();// 停止传输transport.shutdownNow();}}
}执行Echoclient：
java -classpath grizzly-framework.jar EchoClient已经通过測试，程序执行的非常完美。