NIO-UDP实例

DatagramChannelImpl 解析一（初始化）：[url]http://donald-draper.iteye.com/blog/2373245[/url]
DatagramChannelImpl 解析二（报文发送与接收）：[url]http://donald-draper.iteye.com/blog/2373281[/url]
DatagramChannelImpl 解析三（多播）：[url]http://donald-draper.iteye.com/blog/2373507[/url]
DatagramChannelImpl 解析四（地址绑定，关闭通道等）：[url]http://donald-draper.iteye.com/blog/2373519[/url]
前面讲过nio tcp通信，今天来看一下udp；
Server-peer

package nio.datagramchannel;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.util.Iterator;

/**
 * Sever
 * @author donald
 * 2017年4月11日
 * 下午9:24:03
 */
public class DatagramChannelServer {
	//manager the channel
	private Selector selector;
	/**
	 * stat Server
	 * @param args
	 * @throws IOException
	 */
	public static void main(String[] args) throws IOException{
		DatagramChannelServer server = new DatagramChannelServer();
		server.initServer("192.168.31.153", 10000);
		server.listen();
	}
	/**
	 * get the ServerSocket and finish some initial work
	 * @param port
	 * @throws IOException
	 */
	public void initServer(String host, int port) throws IOException{
		//get the ServerSocket
		DatagramChannel serverChannel = DatagramChannel.open();
		// set no blocking mode
		serverChannel.configureBlocking(false);
		//bind the port
		serverChannel.socket().bind(new InetSocketAddress(host, port));
		//get the channel manager
		this.selector = Selector.open();
		//Register the channel to manager and bind the event
		serverChannel.register(selector,SelectionKey.OP_READ);
		}
	/**
	 * use asking mode to listen the event of selector
	 * @throws IOException 
	 */
	@SuppressWarnings("rawtypes")
	public void listen() throws IOException{
		System.out.println("=========The Server is start!===========");
		while(true){
			selector.select();
			Iterator ite =  this.selector.selectedKeys().iterator();
			while(ite.hasNext()){
				SelectionKey key = (SelectionKey)ite.next();
				ite.remove();
				if (key.isReadable()) read(key);
			}

		}
	}
	/**
	 * deal with the message come from the client
	 * @param key
	 * @throws IOException 
	 */
	public void read(SelectionKey key) throws IOException{
		DatagramChannel channel = (DatagramChannel) key.channel();
		ByteBuffer buf = ByteBuffer.allocate(100);
		//用receive读取数据，如果用read，必须使用connect方法连接Server，并确保建立连接，write一样
		InetSocketAddress socketAddress = (InetSocketAddress) channel.receive(buf); 
		System.out.println("client ip and port:"+socketAddress.getHostString()+","+socketAddress.getPort());
		byte[] data = buf.array();
		String msg = new String(data).trim();
		System.out.println("message come from client:"+msg);
		channel.send(ByteBuffer.wrap(new String("Hello client!").getBytes()),socketAddress);
		channel.close();
	}	
}

Client-peer

package nio.datagramchannel;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.util.Iterator;

/**
 * Client
 * @author donald
 * 2017年4月11日
 * 下午9:24:09
 */
public class DatagramChannelClient {
	//manager the channel
	private Selector selector;
	/**
	 * stat Client
	 * @param args
	 * @throws IOException
	 */
	public static void main(String[] args) throws IOException{
		DatagramChannelClient client = new DatagramChannelClient();
		client.initClient("192.168.31.153",10001);
		client.listen();
	}
	/**
	 * get the Socket and finish some initial work
	 * @param ip Server ip
	 * @param port connect Server port
	 * @throws IOException
	 */
	public void initClient(String ip,int port) throws IOException{
		//get the Socket
		DatagramChannel channel = DatagramChannel.open();
		// set no blocking mode
		channel.configureBlocking(false);
		channel.socket().bind(new InetSocketAddress(ip,port));
		//get the channel manager
		this.selector = Selector.open();
		//Register the channel to manager and bind the event
		channel.register(selector,SelectionKey.OP_READ);
		//发送数据到Server
		channel.send(ByteBuffer.wrap(new String("Hello Server!").getBytes()),new InetSocketAddress("192.168.31.153", 10000));
		}
	/**
	 * use asking mode to listen the event of selector
	 * @throws IOException 
	 */
	@SuppressWarnings("rawtypes")
	public void listen() throws IOException{
		System.out.println("===========The Client is start!===========");
		while(true){
			selector.select();
			Iterator ite =  this.selector.selectedKeys().iterator();
			while(ite.hasNext()){
				SelectionKey key = (SelectionKey)ite.next();
				ite.remove();
				if (key.isReadable()) read(key);
			}

		}
	}
	/**
	 * deal with the message come from the server
	 * @param key
	 * @throws IOException 
	 */
	public void read(SelectionKey key) throws IOException{
		DatagramChannel channel = (DatagramChannel) key.channel();
		ByteBuffer buf = ByteBuffer.allocate(100);
		//用receive读取数据，如果用read，必须使用connect方法连接Server，并确保建立连接，write一样
		InetSocketAddress socketAddress = (InetSocketAddress) channel.receive(buf); 
		System.out.println("server ip and port:"+socketAddress.getHostString()+","+socketAddress.getPort());
		byte[] data = buf.array();
		String msg = new String(data).trim();
		System.out.println("message come from server:"+msg);
		channel.close();
	}

}

先启动Server-peer，后启动Client-peer，控制台输出：
Server-peer：
=========The Server is start!===========
client ip and port:192.168.31.153,10001
message come from client:Hello Server!

Client-peer：
===========The Client is start!===========
server ip and port:192.168.31.153,10000
message come from server:Hello client!
上面的报文通道使用实例用的是send和receive方法发送和接收报文，是不需要提前建立连接的。
我们看用read和write方法发送和接收报文
Server-peer：

package nio.datagramchannel;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.util.Iterator;

/**
 * Sever
 * @author donald
 * 2017年4月11日
 * 下午9:24:03
 */
public class UdpServer {
	//manager the channel
	private Selector selector;
	/**
	 * stat Server
	 * @param args
	 * @throws IOException
	 */
	public static void main(String[] args) throws IOException{
		UdpServer server = new UdpServer();
		server.initServer("192.168.31.153", 10000);
		server.listen();
	}
	/**
	 * get the ServerSocket and finish some initial work
	 * @param port
	 * @throws IOException
	 */
	public void initServer(String host, int port) throws IOException{
		//get the ServerSocket
		DatagramChannel serverChannel = DatagramChannel.open();
		// set no blocking mode
		serverChannel.configureBlocking(false);
		//bind the port
		serverChannel.socket().bind(new InetSocketAddress(host, port));
		//get the channel manager
		this.selector = Selector.open();
		//Register the channel to manager and bind the event
		serverChannel.register(selector,SelectionKey.OP_READ);
		serverChannel.connect(new InetSocketAddress("192.168.31.153", 10001));
		while(!serverChannel.isConnected()){
			//空转等待连接
		}
	}
	/**
	 * use asking mode to listen the event of selector
	 * @throws IOException 
	 */
	@SuppressWarnings("rawtypes")
	public void listen() throws IOException{
		System.out.println("=========The Server is start!===========");
		while(true){
			selector.select();
			Iterator ite =  this.selector.selectedKeys().iterator();
			while(ite.hasNext()){
				SelectionKey key = (SelectionKey)ite.next();
				ite.remove();
				if (key.isReadable()) read(key);
			}

		}
	}
	/**
	 * deal with the message come from the client
	 * @param key
	 * @throws IOException 
	 */
	public void read(SelectionKey key) throws IOException{
		DatagramChannel channel = (DatagramChannel) key.channel();
		System.out.println("is Connected："+channel.isConnected());
		ByteBuffer buf = ByteBuffer.allocate(100);
		InetSocketAddress socketAddress = (InetSocketAddress) channel.getRemoteAddress(); 
		System.out.println("client ip and port:"+socketAddress.getHostString()+","+socketAddress.getPort());
		channel.read(buf);
		byte[] data = buf.array();
		String msg = new String(data).trim();
		System.out.println("message come from client:"+msg);
		channel.write(ByteBuffer.wrap(new String("Hello client!").getBytes()));
		channel.close();
	}

}

Client-peer：

package nio.datagramchannel;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.util.Iterator;

/**
 * Client
 * @author donald
 * 2017年4月11日
 * 下午9:24:09
 */
public class UdpClient {
	//manager the channel
	private Selector selector;
	/**
	 * stat Client
	 * @param args
	 * @throws IOException
	 */
	public static void main(String[] args) throws IOException{
		UdpClient client = new UdpClient();
		client.initClient("192.168.31.153",10001);
		client.listen();
	}
	/**
	 * get the Socket and finish some initial work
	 * @param ip Server ip
	 * @param port connect Server port
	 * @throws IOException
	 */
	public void initClient(String ip,int port) throws IOException{
		//get the Socket
		DatagramChannel channel = DatagramChannel.open();
		// set no blocking mode
		channel.configureBlocking(false);
		channel.socket().bind(new InetSocketAddress(ip,port));
		//get the channel manager
		this.selector = Selector.open();
		//Register the channel to manager and bind the event
		channel.register(selector,SelectionKey.OP_READ);
		channel.connect(new InetSocketAddress("192.168.31.153", 10000));
		while(!channel.isConnected()){
			//空转等待连接
		}
		channel.write(ByteBuffer.wrap(new String("Hello Server!").getBytes()));
		System.out.println("client send message to server is done!");
    }
	/**
	 * use asking mode to listen the event of selector
	 * @throws IOException 
	 */
	@SuppressWarnings("rawtypes")
	public void listen() throws IOException{
		System.out.println("===========The Client is start!===========");
		while(true){
			selector.select();
			Iterator ite =  this.selector.selectedKeys().iterator();
			while(ite.hasNext()){
				SelectionKey key = (SelectionKey)ite.next();
				ite.remove();
				if (key.isReadable()) read(key);
			}

		}
	}
	/**
	 * deal with the message come from the server
	 * @param key
	 * @throws IOException 
	 */
	public void read(SelectionKey key) throws IOException{
		DatagramChannel channel = (DatagramChannel) key.channel();
		System.out.println("is Connected："+channel.isConnected());
		ByteBuffer buf = ByteBuffer.allocate(100);
		InetSocketAddress socketAddress = (InetSocketAddress) channel.getRemoteAddress(); 
		System.out.println("server ip and port:"+socketAddress.getHostString()+","+socketAddress.getPort());
		channel.read(buf); 
		byte[] data = buf.array();
		String msg = new String(data).trim();
		System.out.println("message come from server:"+msg);
		channel.close();
	}

}

先启动Server-peer，后启动Client-peer，控制台输出：
Server-peer：
=========The Server is start!===========
is Connected：true
client ip and port:192.168.31.153,10001
message come from client:Hello Server!


Client-peer：
client send message to server is done!
===========The Client is start!===========
is Connected：true
server ip and port:192.168.31.153,10000
message come from server:Hello client!
[size=medium][b]总结：[/b][/size]
[color=blue]send和receive方法发送和接收报文，是不需要提前建立连接的，而read和write方法，
是要建立连接的与SocketChannel相同。建议用send和receive方法发送和接收报文。
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