Java 停止并等待UDP服务器
我正在尝试编写一个Java停止等待UDP服务器,我已经完成了这一步,但我不确定下一步该怎么做。我希望客户端向服务器发送消息,设置超时,等待响应,如果没有响应,则重新发送数据包,如果没有响应,则增加序列号,直到达到10,并与服务器保持发送和接收消息 我已经走了这么远,我该怎么解决这个问题Java 停止并等待UDP服务器,java,sockets,udp,Java,Sockets,Udp,我正在尝试编写一个Java停止等待UDP服务器,我已经完成了这一步,但我不确定下一步该怎么做。我希望客户端向服务器发送消息,设置超时,等待响应,如果没有响应,则重新发送数据包,如果没有响应,则增加序列号,直到达到10,并与服务器保持发送和接收消息 我已经走了这么远,我该怎么解决这个问题 import java.io.*; import java.net.*; public class Client { public static void main(String args[]) throw
import java.io.*;
import java.net.*;
public class Client {
public static void main(String args[]) throws Exception {
byte[] sendData = new byte[1024];
byte[] receiveData = new byte[1024];
InetAddress IPAddress = null;
try {
IPAddress = InetAddress.getByName("localhost");
} catch (UnknownHostException exception) {
System.err.println(exception);
}
//Create a datagram socket object
DatagramSocket clientSocket = new DatagramSocket();
while(true) {
String sequenceNo = "0";
sendData = sequenceNo.getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 6789);
clientSocket.send(sendPacket);
clientSocket.setSoTimeout(1);
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
if(clientSocket.receive(receivePacket)==null)
{
clientSocet.send(sendPacket);
}else { //message sent and acknowledgement received
sequenceNo++; //increment sequence no.
//Create a new datagram packet to get the response
String modifiedSentence = sequenceNo;
//Print the data on the screen
System.out.println("From : " + modifiedSentence);
//Close the socket
if(sequenceNo >= 10 ) {
clientSocket.close();
}
}}}}
我看到的第一个问题(除了会停止代码编译的错误输入变量名)是套接字超时:如果套接字超时过期,
receive
函数将抛出一个SocketTimeoutException
,而您的代码不处理它,因此,结果不能与null
进行比较。相反,您需要这样做:
try {
clientSocket.receive(receivePacket);
sequenceNo++;
... // rest of the success path
} catch (SocketTimeoutException ex) {
clientSocket.send(sendPacket);
}