UDP/IP 阻塞模式与非阻塞模式

package concurrentTest;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;

/**
 * UDP/IP阻塞模式
 * */

public class UDPBIO {

	/**
	 * 服务器端和客户端类似 
	 * @param ipStr IP地址
	 * @param portNum 端口号
	 * */	
	
	public void udpListen(String ipStr, int portNum)
	{
		try {
			//若希望是全双工模式，则启动一个监听端口，承担服务器的职责
			//若不能绑定到指定端口，则抛出SocketException
			DatagramSocket serverSocket = new DatagramSocket(portNum);
			InetAddress server = InetAddress.getByName(ipStr);
			byte[] buffer = new byte[65507];
			DatagramPacket receivePacket = new DatagramPacket(buffer,buffer.length);
			DatagramSocket socket = new DatagramSocket();
			DatagramPacket packet = new DatagramPacket(buffer,buffer.length,server,portNum);
			
			//阻塞发送packet到指定的服务器和端口
			//网络IO异常，抛出IOExceprion
			//连不上IP和端口，抛出PortUnreachableException
			socket.send(packet);
			
			//阻塞并同步读取流信息，如接收到的信息流比packet长，则删除更长的信息
			serverSocket.receive(receivePacket);
			
		} catch (SocketException e) {
			// 若不能绑定到指定端口
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub

	}

}

============================================================================================================================================================================================================================================================================================================================================================================================================

package concurrentTest;

import java.io.IOException;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.MulticastSocket;
import java.net.SocketAddress;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;


/**
 * UDP/IP非阻塞模式
 * */
public class UDPNIO {

	/**
	 * 服务器端和客户端类似 
	 * @param ipStr IP地址
	 * @param portNum 端口号
	 * */		
	
	public void udpListen(String ipStr, int portNum)
	{
		try {
			ByteBuffer buffer = ByteBuffer.allocate(1024);
			DatagramChannel reveiveChannel = DatagramChannel.open();
			reveiveChannel.configureBlocking(false);
			DatagramSocket socket = reveiveChannel.socket();
			socket.bind(new InetSocketAddress(portNum));
			Selector selector = Selector.open();
			reveiveChannel.register(selector, SelectionKey.OP_READ);
			
			//之后可采取和TCP/IP NIO中对selector遍历方式进行流信息的读取
			DatagramChannel sendChannel = DatagramChannel.open();
			sendChannel.configureBlocking(false);
			SocketAddress target = new InetSocketAddress(InetAddress.getLocalHost(), portNum);
			sendChannel.connect(target);
			
			//阻塞写入流，若发送缓冲区已满，返回0，此时可继续注册OP_WRITE事件
			sendChannel.write(buffer);
		} catch (SocketException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	
	
	/**
	 * 组播
	 * */
	public void multicaseListen(String ipStr, int portNum)
	{
		try {
			InetAddress groupAddress = InetAddress.getByName(ipStr);
			MulticastSocket server = new MulticastSocket(portNum);
			
			//加入组播，若地址为非组播地址，抛出IOException
			//若不希望再发送数据到组播地址或者不希望再读取数据，可调用server.leaveGroup(组播地址)
			server.joinGroup(groupAddress);
			MulticastSocket client = new MulticastSocket();
			client.joinGroup(groupAddress);
			
			//
			
		} catch (UnknownHostException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// 若地址为非组播地址
			e.printStackTrace();
		}
	}
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub

	}

}