标签：ddr localhost lin 指定 接收 使用 程序 support public
UDP编程中，如果要完成通信，通信双方必须要创建DatagramSocket，通过DatagramSocket完成通信。
数据报包用来实现无连接包投递服务。每条报文仅根据该包中包含的信息从一台机器路由到另一台机器
UDP步骤:
[1] 创建一个DatagramSocket用于表示发送端，通过send方法发送数据报
[2] 创建一个DatagramSocket用于表示接收端，通过receive方法发送数据报
发送端：
public class UDPDemo1 {
public static void main(String[] args) {
System.out.println("发送端开始发送信息...");
try {
//1.创建Socket，指定端口号
DatagramSocket datagramSocket=new DatagramSocket(9000);
//2.把发送的信息打包
String string="IG 牛逼！";
byte[] bytes = string.getBytes("UTF-8");
DatagramPacket datagramPacket=new DatagramPacket(bytes, bytes.length, InetAddress.getLocalHost(),8000);
//3.通过socket的send方法，把信息传出
datagramSocket.send(datagramPacket);
//4.关闭socket
datagramSocket.close();
} catch (SocketException e) {
e.printStackTrace();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
接收端：
public class UDPDemo01 {
public static void main(String[] args) {
System.out.println("接收端开始接受信息...");
try {
DatagramSocket datagramSocket=new DatagramSocket(8000);
byte[] buf=new byte[1024];
DatagramPacket datagramPacket=new DatagramPacket(buf, buf.length);
datagramSocket.receive(datagramPacket);
String string=new String(buf, 0, datagramPacket.getLength(), "UTF-8");
System.out.println(string);
datagramSocket.close();
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
这一端：
public class UDPdouble {
public static void main(String[] args) {
System.out.println("创建连接...");
Scanner scanner=new Scanner(System.in);
DatagramSocket socket=null;
try {
socket=new DatagramSocket(8002);
while(true){
//1.A向B发送信息
System.out.print("A说：");
String Astring = scanner.nextLine();
byte[] buf = Astring.getBytes("UTF-8");
DatagramPacket datagramPacket=new DatagramPacket(buf, buf.length,
InetAddress.getLocalHost(),9002);
socket.send(datagramPacket);
//2.A接受B的信息
byte[] buf2=new byte[1024];
DatagramPacket datagramPacket2=new DatagramPacket(buf2, buf2.length);
socket.receive(datagramPacket2);
String bstring=new String(buf2, 0, datagramPacket2.getLength(), "UTF-8");
System.out.println("B说："+bstring);
}
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
socket.close();
}
}
}
另一端：
public class UDPdouble {
public static void main(String[] args) {
System.out.println("创建连接...");
Scanner scanner=new Scanner(System.in);
DatagramSocket socket=null;
try {
socket=new DatagramSocket(9002);
while(true){
//1.B接受A的信息
byte[] buf=new byte[1024];
DatagramPacket datagramPacket=new DatagramPacket(buf, buf.length);
socket.receive(datagramPacket);
String Astring =new String(buf, 0, datagramPacket.getLength(), "UTF-8");
System.out.println("A说："+Astring);
//2.B向A发送信息
System.out.print("B说:");
String bstring=scanner.nextLine();
byte[] buf2=bstring.getBytes("UTF-8");
DatagramPacket datagramPacket2=new DatagramPacket(buf2, 0,buf2.length,
datagramPacket.getAddress(),datagramPacket.getPort() );
socket.send(datagramPacket2);
}
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
socket.close();
}
}
}
注意：运行中，若需要修改代码，请先停止程序，即停止使用端口。否则，修改完毕后，重新启动会报错，因为上次的端口还在使用。
标签：ddr localhost lin 指定 接收 使用 程序 support public
原文地址：https://www.cnblogs.com/luojack/p/10850575.html
