上面图片使用测试工具实现效果。
JAVA代码无法实现,之前可以传输来着。一觉醒了居然不行了,捣鼓一晚上。
package zyb.org.UDP;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
public class UDPClient {
private static final int TIMEOUT = 5000; //设置接收数据的超时时间
private static final int MAXNUM = 5; //设置重发数据的最多次数
public static void main(String args[])throws IOException{
String str_send = "Cmd=Close,Para=1|Left,EndPoint=192.168.8.102:11001";
String unicode_Str = gbEncoding(str_send);
byte[] buf = new byte[1024];
//客户端在9000端口监听接收到的数据
DatagramSocket ds = new DatagramSocket(11001);
InetAddress loc = InetAddress.getLocalHost();
//定义用来发送数据的DatagramPacket实例
DatagramPacket dp_send= new DatagramPacket(unicode_Str.getBytes(),unicode_Str.length(),loc,11003);
//定义用来接收数据的DatagramPacket实例
DatagramPacket dp_receive = new DatagramPacket(buf, 1024);
//数据发向本地3000端口
ds.setSoTimeout(TIMEOUT); //设置接收数据时阻塞的最长时间
int tries = 0; //重发数据的次数
boolean receivedResponse = false; //是否接收到数据的标志位
//直到接收到数据,或者重发次数达到预定值,则退出循环
while(!receivedResponse && tries<MAXNUM){
//发送数据
ds.send(dp_send);
try{
//接收从服务端发送回来的数据
ds.receive(dp_receive);
//如果接收到的数据不是来自目标地址,则抛出异常
if(!dp_receive.getAddress().equals(loc)){
throw new IOException("Received packet from an umknown source");
}
//如果接收到数据。则将receivedResponse标志位改为true,从而退出循环
receivedResponse = true;
}catch(InterruptedIOException e){
//如果接收数据时阻塞超时,重发并减少一次重发的次数
tries += 1;
System.out.println("Time out," + (MAXNUM - tries) + " more tries..." );
}
}
if(receivedResponse){
//如果收到数据,则打印出来
System.out.println("client received data from server:");
String str_receive = new String(dp_receive.getData(),0,dp_receive.getLength()) +
" from " + dp_receive.getAddress().getHostAddress() + ":" + dp_receive.getPort();
System.out.println(str_receive);
//由于dp_receive在接收了数据之后,其内部消息长度值会变为实际接收的消息的字节数,
//所以这里要将dp_receive的内部消息长度重新置为1024
dp_receive.setLength(1024);
}else{
//如果重发MAXNUM次数据后,仍未获得服务器发送回来的数据,则打印如下信息
System.out.println("No response -- give up.");
}
ds.close();
}
/*
* 中文转unicode编码
*/
public static String gbEncoding(final String gbString) {
char[] utfBytes = gbString.toCharArray();
String unicodeBytes = "";
for (int i = 0; i < utfBytes.length; i++) {
String hexB = Integer.toHexString(utfBytes[i]);
if (hexB.length() <= 2) {
hexB = "00" + hexB;
}
unicodeBytes = unicodeBytes + "\\u" + hexB;
}
return unicodeBytes;
}
/*
* unicode编码转中文
*/
public static String decodeUnicode(final String dataStr) {
int start = 0;
int end = 0;
final StringBuffer buffer = new StringBuffer();
while (start > -1) {
end = dataStr.indexOf("\\u", start + 2);
String charStr = "";
if (end == -1) {
charStr = dataStr.substring(start + 2, dataStr.length());
} else {
charStr = dataStr.substring(start + 2, end);
}
char letter = (char) Integer.parseInt(charStr, 16); // 16进制parse整形字符串。
buffer.append(new Character(letter).toString());
start = end;
}
return buffer.toString();
}
}