UDP传送文件练习

采用流 的方式传送数据写文件

 

程序

package net; //import java.io.BufferedReader; import java.io.FileOutputStream; //import java.io.IOException; //import java.io.InputStreamReader; import java.io.OutputStream; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import java.io.InputStream; import java.io.FileInputStream; import java.io.File; public class TransFile { String ipString; int port; public TransFile() {} public TransFile(String portStr) { port = Integer.parseInt(portStr); } public void send(String ip) throws Exception { DatagramSocket ds = new DatagramSocket(port);//不用指定网卡ip InputStream in = new FileInputStream(new File("a.txt")); byte[] b = new byte[10240]; int c = in.read(b); in.close(); System.out.println(b); DatagramPacket dp = new DatagramPacket(b, c, InetAddress.getByName(ip), port);// ds.send(dp); System.out.println("over"); } public void recv() throws Exception { //Receive byte[] b = new byte[10240]; DatagramSocket ds2 = new DatagramSocket(port); DatagramPacket dp2 = new DatagramPacket(b,b.length); ds2.receive(dp2); OutputStream out=new FileOutputStream(new File("out.txt")); out.write(dp2.getData()); out.close(); } public static void main(String [] args) throws Exception { if (args[0].equals("send")) { if (args.length < 3) { System.out.println("Please put in the ip-address where you want to send the file and the port"); return; } TransFile tf = new TransFile(args[2]); tf.send(args[1]); } if (args[0].equals("recv")) { TransFile tf = new TransFile(args[1]); tf.recv(); } } }

 

测试

1台机器上

$ java net.TransFile send 10.96.19.70 55555
[B@14b7453
over
$

 

当前目录中a.txt

have a test
2010-2-22

-------

10.96.19.70 机器

 

java net.TransFile recv 55555

 

生成了新的文件out.txt

cat out.txt
have a test
2010-2-22

 

 

==========

DatagramSocket 是通道，提供发送，接收方法
DatagramPacket 是数据包（包裹），发送的时候要写上地址

这样就很容易理解了