title: UDP
date: 2021-06-07 22:42:01
tags: NET
categories: Java
description:
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UDP
基本介绍
DatagramSocket有两种常用的构造函数。一种是无需任何参数的，常用于客户端;另一种需要指定端口，常用于服务器端。如下所示：
DatagramSocket() ：构造数据报套接字并将其绑定到本地主机上任何可用的端口。
DatagramSocket(int port) ：创建数据报套接字并将其绑定到本地主机上的指定端口。
常用方法：
Ø send(DatagramPacket p) ：从此套接字发送数据报包。
Ø receive(DatagramPacket p) ：从此套接字接收数据报包。
Ø close() ：关闭此数据报套接字。
Ø DatagramPacket(byte[] buf, int length) ：构造数据报包，用来接收长度为 length 的数据包。
Ø DatagramPacket(byte[] buf, int length, InetAddress address, int port) ：构造数据报包，用来将长度为 length 的包发送到指定主机上的指定端口号。
Ø getAddress() ：获取发送或接收方计算机的IP地址，此数据报将要发往该机器或者是从该机器接收到的。
Ø getData() ：获取发送或接收的数据。
Ø setData(byte[] buf) ：设置发送的数据。
UDP通信编程基本步骤
1. 创建客户端的DatagramSocket，创建时，定义客户端的监听端口。
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创建服务器端的DatagramSocket，创建时，定义服务器端的监听端口。
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在服务器端定义DatagramPacket对象，封装待发送的数据包。
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客户端将数据报包发送出去。
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服务器端接收数据报包。
UDP实例
UDP Client
// 1、使用DatagramSocket指定端口创建发送端
DatagramSocket clientSocket = new DatagramSocket(9999);
//2、准备数据-定转成字节数组
String data = "案发时官方";
byte[] datas = data.getBytes("utf-8");
//3. 封装成DatagramPacket包裹，需要指定目的地
DatagramPacket dataPacket = new DatagramPacket(datas,0,datas.length,new InetSocketAddress("localhost",8888));
//4、 发送包裹send(DatagramPacket p)
clientSocket.send(dataPacket);
// 5.释放资源
clientSocket.close();
UDP Server
// 1、使用DatagramSocket指定端口创建接收端
DatagramSocket serviceSocket = new DatagramSocket(8888);
//2、准备容器封装成DatagramPacket包裹
byte[] container = new byte[1024*60];
DatagramPacket dataPacket = new DatagramPacket(container,0,container.length);
// 3、阻塞式接收包裹receive(DatagramPacket p)
serviceSocket.receive(dataPacket);
//4、分析数据
// byte[] getData(
// getLength(
byte[] datas = dataPacket.getData();
int len = dataPacket.getLength();
System.out.println(new String(datas,0,len));
//5释放资源
serviceSocket.close();
UDP File Client
// 1、使用DatagramSocket指定端口创建发送端
DatagramSocket clientSocket = new DatagramSocket(9999);
//2、准备数据-定转成字节数组
String data = "案发时官方";
byte[] datas = data.getBytes("utf-8");
//3. 封装成DatagramPacket包裹，需要指定目的地
DatagramPacket dataPacket = new DatagramPacket(datas,0,datas.length,new InetSocketAddress("localhost",8888));
//4、 发送包裹send(DatagramPacket p)
clientSocket.send(dataPacket);
// 5.释放资源
clientSocket.close();
UDP File Server
// 1、使用DatagramSocket指定端口创建接收端
DatagramSocket serviceSocket = new DatagramSocket(8888);
//2、准备容器封装成DatagramPacket包裹
byte[] container = new byte[1024*60];
DatagramPacket dataPacket = new DatagramPacket(container,0,container.length);
// 3、阻塞式接收包裹receive(DatagramPacket p)
serviceSocket.receive(dataPacket);
//4、分析数据
// byte[] getData(
// getLength(
byte[] datas = dataPacket.getData();
int len = dataPacket.getLength();
//5释放资源
serviceSocket.close();
UDP Object Client
// 1、使用DatagramSocket指定端口创建发送端
DatagramSocket clientSocket = new DatagramSocket(8888);
//2、准备数据-定转成字节数组
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(new BufferedOutputStream(byteArrayOutputStream));
oos.writeUTF("啦啦啦啦");
People people = new People();
people.setName("aaaa");
people.setAge(18);
oos.writeObject(people);
oos.flush();
byte[] bytes = byteArrayOutputStream.toByteArray();
//3. 封装成DatagramPacket包裹，需要指定目的地
DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length, new InetSocketAddress("localhost", 9999));
//4、 发送包裹send(DatagramPacket p)
clientSocket.send(packet);
// 5.释放资源
clientSocket.close();
UDP Object Server
// 1、使用DatagramSocket指定端口创建接收端
DatagramSocket serverSocket = new DatagramSocket(9999);
//2、准备容器封装成DatagramPacket包裹
byte[] container = new byte[1024*60];
DatagramPacket packet = new DatagramPacket(container, 0, container.length);
// 3、阻塞式接收包裹receive(DatagramPacket p)
serverSocket.receive(packet);
//4、分析数据
// byte[] getData(
// getLength(
byte[] data = packet.getData();
ObjectInputStream ois = new ObjectInputStream(new BufferedInputStream(new ByteArrayInputStream(data)));
Object str = ois.readUTF();
Object sb = ois.readObject();
if (str instanceof String){
String a = (String)str;
System.out.println("String："+a);
}
if (sb instanceof People){
People a = (People)sb;
System.out.println("年龄："+a.getAge());
}
//5释放资源
serverSocket.close();
UDP Talk Client
// 1、使用DatagramSocket指定端口创建发送端
DatagramSocket clientSocket = new DatagramSocket(9999);
//2、准备数据-定转成字节数组
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
while (true){
String data = bufferedReader.readLine();
byte[] datas = data.getBytes("utf-8");
//3. 封装成DatagramPacket包裹，需要指定目的地
DatagramPacket dataPacket = new DatagramPacket(datas,0,datas.length,new InetSocketAddress("localhost",8888));
//4、 发送包裹send(DatagramPacket p)
clientSocket.send(dataPacket);
if (data.equalsIgnoreCase("exit")){
break;
}
}
// 5.释放资源
clientSocket.close();
UDP Talk Server
// 1、使用DatagramSocket指定端口创建接收端
DatagramSocket serverSocket = new DatagramSocket(8888);
//2、准备容器封装成DatagramPacket包裹
while (true){
byte[] container = new byte[1024*60];
DatagramPacket dataPacket = new DatagramPacket(container,0,container.length);
// 3、阻塞式接收包裹receive(DatagramPacket p)
serverSocket.receive(dataPacket);
//4、分析数据
// byte[] getData(
// getLength(
byte[] datas = dataPacket.getData();
int len = dataPacket.getLength();
String da = new String(datas,0,len);
System.out.println(da);
if (da.equalsIgnoreCase("exit")){
break;
}
}
//5释放资源
serverSocket.close();
Tread UDP
public class ClientStudent { public static void main(String[] args) { new Thread(new TalkSend(7777,"localhost",6666)).start(); new Thread(new TalkRecive(9999)).start(); }}-----------------------------------------------------------------------------------------------------public class ClientTeacher { public static void main(String[] args) { new Thread(new TalkSend(8888,"localhost",9999)).start(); new Thread(new TalkRecive(6666)).start(); }}-----------------------------------------------------------------------------------------------------public class TalkRecive implements Runnable { private DatagramSocket serverSocket; public TalkRecive(int port){ try { serverSocket = new DatagramSocket(port); } catch (SocketException e) { e.printStackTrace(); } } @Override public void run() { while (true){ byte[] container = new byte[1024*60]; DatagramPacket dataPacket = new DatagramPacket(container,0,container.length); // 3、阻塞式接收包裹receive(DatagramPacket p) try { serverSocket.receive(dataPacket); //4、分析数据 // byte[] getData( // getLength( byte[] datas = dataPacket.getData(); int len = dataPacket.getLength(); String da = new String(datas,0,len); System.out.println(da); if (da.equalsIgnoreCase("exit")){ break; } } catch (IOException e) { e.printStackTrace(); } } serverSocket.close(); }}-----------------------------------------------------------------------------------------------------public class TalkSend implements Runnable { private DatagramSocket clientSocket; private BufferedReader bufferedReader; private String toIP; private int toPort; public TalkSend(int Port,String toIP,int toPort){ this.toIP = toIP; this.toPort = toPort; try { clientSocket = new DatagramSocket(Port); bufferedReader = new BufferedReader(new InputStreamReader(System.in)); } catch (SocketException e) { e.printStackTrace(); } } @Override public void run() { while (true){ String data = null; try { data = bufferedReader.readLine(); byte[] datas = data.getBytes("utf-8"); //3. 封装成DatagramPacket包裹，需要指定目的地 DatagramPacket dataPacket = new DatagramPacket(datas,0,datas.length,new InetSocketAddress(this.toIP,this.toPort)); //4、 发送包裹send(DatagramPacket p) clientSocket.send(dataPacket); if (data.equalsIgnoreCase("exit")){ break; } } catch (IOException e) { e.printStackTrace(); } } clientSocket.close(); }}