java udp 广播及socket通讯

UDP通讯

udp 是一种网络通信协议，不需要客户端和服务器端建立连接即可进行通讯功能。相对于Tcp协议它有着tcp用很多优点，例如广播功能。udp的广播功能可以指定特定网段进行广播内容，而无需知道接收者是谁，只有接受者在广播范围内即可接收广播内容。其实基于这个功能可以实现一个局域网群聊室的功能。

udp广播发送有两种形式，

方式一：通过DatagramSocket实现

方式二：通过MulticastSocket 实现

方式一：demo;

1,数据发送端：

import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.SocketException;import java.net.UnknownHostException;public class SendIP {public static void main(String args[]) {new SendIP().lanchApp(); }private void lanchApp(){SendThread th=new SendThread();th.start();}private class SendThread extends Thread{@Overridepublic void run() {while(true){try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}try {BroadcastIP();} catch (Exception e) {e.printStackTrace();}}}private void BroadcastIP()throws Exception{ DatagramSocket dgSocket=new DatagramSocket();  byte b[]="你好，这是我发给你的消息".getBytes();  DatagramPacket dgPacket=new DatagramPacket(b,b.length,InetAddress.getByName("255.255.255.255"),8989);  dgSocket.send(dgPacket);  dgSocket.close();  System.out.println("send message is ok.");}}}

2，数据接收端：

import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.SocketException;import java.util.regex.Matcher;import java.util.regex.Pattern;public class SearchIP{ public static void main(String args[])throws Exception{  new SearchIP().lanchApp(); }  private void lanchApp(){ receiveThread th=new receiveThread();th.start();}  private class receiveThread extends Thread{ @Overridepublic void run() {while(true){try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}try {receiveIP();} catch (Exception e) {e.printStackTrace();}} } private void receiveIP() throws Exception{ DatagramSocket dgSocket=new DatagramSocket(8989);  byte[] by=new byte[1024];  DatagramPacket packet=new DatagramPacket(by,by.length);  dgSocket.receive(packet);    String str=new String(packet.getData(),0,packet.getLength());    System.out.println("接收到数据大小:"+str.length());  System.out.println("接收到的数据为："+str);  dgSocket.close();  System.out.println("recevied message is ok."); } } }

整合封装一个类管理：

import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetSocketAddress;import java.net.Socket;import java.net.SocketException;import java.net.UnknownHostException;public class NetClient {String ip;private int udp_port;private DatagramSocket ds=null;public void connect(String ip,int port){this.ip=ip;this.udp_port=port;try {ds=new DatagramSocket(udp_port);} catch (SocketException e1) {e1.printStackTrace();}new Thread(new UDPThread()).start();}private class UDPThread implements Runnable{byte[] buf=new byte[1024];@Overridepublic void run() {while(ds!=null){DatagramPacket dp=new DatagramPacket(buf, buf.length);try {ds.receive(dp);parse(dp);System.out.println("receive a package from server");} catch (IOException e) {e.printStackTrace();}}}private void parse(DatagramPacket dp) {ByteArrayInputStream bais = new ByteArrayInputStream(buf, 0, dp.getLength());DataInputStream dis = new DataInputStream(bais);String msg=null;try {msg=dis.readUTF();} catch (IOException e) {e.printStackTrace();}}}/** * send data package to server * @param ds * @param ip * @param udpPort */public void sendMsg(String str) {if(ds==null)return;ByteArrayOutputStream baos=new ByteArrayOutputStream();DataOutputStream dos=new DataOutputStream(baos);try {dos.write(str.getBytes("UTF-8"));dos.flush();} catch (IOException e) {e.printStackTrace();}byte[] buf=baos.toByteArray();try {DatagramPacket dp=new DatagramPacket(buf, buf.length, new InetSocketAddress(ip, udp_port));ds.send(dp);} catch (SocketException e) {Log.e("udpmsg", e.getMessage());} catch (IOException e) {Log.e("udpmsg", e.getMessage());}}

方式二demo;

1,数据发送端：

import java.io.IOException;import java.net.DatagramPacket;import java.net.InetAddress;import java.net.MulticastSocket;public class MulBroadcast extends Thread{String info ="节目预告： 恭喜您中500w彩票了";      int port =9898;      InetAddress address;    MulticastSocket socket;         public MulBroadcast(){   try{   address=InetAddress.getByName("233.0.0.0");         socket=new MulticastSocket(port);         socket.setTimeToLive(1);         socket.joinGroup(address);     }catch(IOException e){   e.printStackTrace();   }    }       @Override   //最简单的方法也就是建立一个线程来运行       public void run(){          while(true){              byte[] data=info.getBytes();              DatagramPacket packet=new DatagramPacket(data,data.length,address,port);                          try {              socket.send(packet);                 Thread.sleep(3000);            } catch (Exception e) {                  e.printStackTrace();              }              System.out.println("消息已发送：");          }      }          public static void main(String[] args){          new MulBroadcast().start();    }      }

2，数据接收端：

import java.io.IOException;import java.net.DatagramPacket;import java.net.InetAddress;import java.net.MulticastSocket;public class MulReceiverIP extends Thread{ int port=9898;      InetAddress group;      MulticastSocket socket; //socket sends and receives the packet.       DatagramPacket packet;     byte[] buf=new byte[30];// If the message is longer than the packet's length, the message is truncated.    public MulReceiverIP(){ try {              socket=new MulticastSocket(port);                      group=InetAddress.getByName("233.0.0.0");             socket.joinGroup(group);    //加入广播组,加入group后,socket发送的数据报,可以被加入到group中的成员接收到。            packet=new DatagramPacket(buf,buf.length);                        } catch (IOException e) {              e.printStackTrace();          }  }  @Override      public void run(){          while(true){              try {                  socket.receive(packet);              } catch (IOException e) {                  e.printStackTrace();              }              //    String message=new String(buf);              String message=new String(packet.getData(),0,packet.getLength());//very important !!              System.out.println("接受消息内容: "+message);                   }      }      public static void main(String[] args) {  new MulReceiverIP().start();}  }

Socket通讯

Android中sockect通讯实质属于Java socket通讯，在Java.NET目录下，主要可分为基于tcp协议socket和基于udp协议的DatagramSocket两个方向网络通讯还离不开输入，输出流的处理 在 java.io/java.nio目录下，其中对于输入输出流的选择，主要看情况选择合适的流进行封装处理。这里我选择的是DataOutputStream ，DataInputStream主要是因为它们可以直接读取和写入基本数据类型方法，省去转换类型的麻烦。

class Client{public static final int port=8882;private Socket s=null;private String str=null;private DataOutputStream dos=null;private DataInputStream dis=null;private boolean bconn=false;private Thread th;public Client(String ip){th=new Thread(new Received());connect(ip);th.start();}private void send_msg(){try {dos=new DataOutputStream(s.getOutputStream());dos.writeUTF(str);dos.flush();} catch (IOException e) {e.printStackTrace();}}public void connect(String ip){try {s=new Socket(ip, port);bconn=true;dis=new DataInputStream(s.getInputStream());} catch (UnknownHostException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}public void release_dis(){try {bconn=false;if(dos!=null){dos.close();dos=null;}if(dis!=null){dis.close();dis=null;}if(s!=null){s.close();s=null;}} catch (IOException e) {e.printStackTrace();}}private class Received implements Runnable{@Overridepublic void run() {try {while(bconn){String msg=dis.readUTF();Log.e("read msg", msg);}} catch(SocketException e){Log.e("quit msg", "has quit");}catch (IOException e) {e.printStackTrace();}}}}