【发布时间】:2013-11-29 12:43:24
【问题描述】:
我正在开发一个使用 UDP 协议的 SMS 应用程序。我的应用程序需要执行以下操作,客户端向另一个客户端发送一条不超过 160 的消息,并且他/她知道另一个客户端 IP 地址。它将通过服务器发送,以防客户端离线。
我开始研究它,但后来我停止了!我对这些事情有疑问。
多个客户端如何发送到服务器?我搜索并读到了一种叫做多线程的东西,谁能解释一下或给我一个例子吗?
另外,我无法想象从客户端获取消息然后保存它的过程。我的意思是服务器如何知道哪个消息属于哪个客户端?
这是我正在处理的代码
服务器:
import java.io.*;
import java.net.*;
class Server {
public static void main(String args[]) throws Exception
{
DatagramSocket serverSocket = new DatagramSocket(9876);
byte[] receiveData = new byte[1024];
byte[] sendData = new byte[1024];
while(true)
{
DatagramPacket receivePacket =
new DatagramPacket(receiveData, receiveData.length);
serverSocket.receive(receivePacket);
String sentence = new String(receivePacket.getData());
InetAddress IPAddress = receivePacket.getAddress();
int port = receivePacket.getPort();
String senderSentence = "From "+IPAddress+" Msg "+sentence;
sendData = senderSentence.getBytes();
DatagramPacket sendPacket =
new DatagramPacket(sendData, sendData.length, IPAddress,
port);
serverSocket.send(sendPacket);
} } }
客户:
import java.io.*;
import java.net.*;
public class Client {
public static void main(String args[]) throws Exception
{
String sentence;
BufferedReader inFromUser =
new BufferedReader(new InputStreamReader(System.in));
DatagramSocket clientSocket = new DatagramSocket();
byte[] sendData = new byte[1024];
byte[] receiveData = new byte[1024];
do {
System.out.println("Enter a msg , NOTE: don't exceed 160 charcter");
sentence = inFromUser.readLine();
}
while(sentence.length() >= 160);
System.out.println("Enter the adress of the other user");
String ip=inFromUser.readLine();
InetAddress IPAddress = InetAddress.getByName(ip);
sendData = sentence.getBytes();
DatagramPacket sendPacket =
new DatagramPacket(sendData, sendData.length, IPAddress, 9876);
clientSocket.send(sendPacket);
DatagramPacket receivePacket =
new DatagramPacket(receiveData, receiveData.length);
clientSocket.receive(receivePacket);
String modifiedSentence =
new String(receivePacket.getData());
System.out.println("FROM SERVER:" + modifiedSentence);
clientSocket.close();
} }
谢谢~
【问题讨论】:
标签: java windows sockets udp sms