Java 如何在局域网中找到在线用户?
我目前正在开发一个小型的点对点应用程序,用户可以在局域网内相互聊天。我目前已经实现了以下代码,以便由一个在线用户广播Java 如何在局域网中找到在线用户?,java,android,networking,lan,Java,Android,Networking,Lan,我目前正在开发一个小型的点对点应用程序,用户可以在局域网内相互聊天。我目前已经实现了以下代码,以便由一个在线用户广播 import java.io.*; import java.net.*; class BroadcastOnline extends Thread{ public void run(){ try{ String string = "a"; DatagramSocket serverSocket = new D
import java.io.*;
import java.net.*;
class BroadcastOnline extends Thread{
public void run(){
try{
String string = "a";
DatagramSocket serverSocket = new DatagramSocket();
InetAddress IPAddress = InetAddress.getByName("255.255.255.255");
byte[] sendData = new byte[1];
sendData = string.getBytes();
for(;;){
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 9877);
serverSocket.send(sendPacket);
Thread.sleep(1000);
}
} catch (Exception e){}
}
}
我用下面的代码找到了那些在线的人
import java.io.*;
import java.net.*;
class FindUsers {
InetAddress ad;
String ipaddress;
String onlineUsers[] = new String [10];
FindUsers() throws Exception{
DatagramSocket clientSocket = new DatagramSocket(9877);
int count=0;
byte[] receiveData = new byte[1];
for(int i=0;i<=9;i++){
DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
clientSocket.receive(receivePacket);
String sentence = new String( receivePacket.getData());
ad = receivePacket.getAddress();
ipaddress = ad.getHostAddress();
onlineUsers[i]=ipaddress;
count++;
}
}
}
import java.io.*;
导入java.net。*;
类FindUsers{
地址广告;
字符串地址;
字符串onlineUsers[]=新字符串[10];
FindUsers()引发异常{
DatagramSocket客户端套接字=新DatagramSocket(9877);
整数计数=0;
字节[]接收数据=新字节[1];
对于(int i=0;i您需要在BroadcastOnline类中广播如下名称:
byte[] sendData = new byte[15];
String name = nameField.getText();
sendData = name.getBytes();
for(;;){
DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 9877);
serverSocket.send(sendPacket);
Thread.sleep(1000);
}
**当然,需要捕获上面的异常
要查找联机用户,请实现以下代码
import java.io.*;
import java.net.*;
import java.util.List;
import java.util.ArrayList;
public class FindUsers{
InetAddress inetAddress;
List<String> ipList = new ArrayList<String>();
List<String> nameList = new ArrayList<String>();
String ipAddress;
String name;
DatagramSocket clientSocket;
DatagramPacket receivePacket;
int count=0;
byte[] receiveData;
long futureTime;
Thread collect;
boolean refresh = true;
public FindUsers(){
futureTime = System.currentTimeMillis()+1100;
try{
clientSocket = new DatagramSocket(9877);
}
catch(IOException e){
e.printStackTrace();
System.out.println(e.toString());
}
collect = new Thread(new Runnable(){
public void run(){
for(;;){
receiveData = new byte[15];
receivePacket = new DatagramPacket(receiveData, receiveData.length);
try{
clientSocket.receive(receivePacket);
inetAddress = receivePacket.getAddress();
ipAddress = inetAddress.getHostAddress();
}
catch(IOException e){
//e.printStackTrace();
}
if(!ipList.contains(ipAddress)){
name = new String( receivePacket.getData());
ipList.add(ipAddress);
nameList.add(name);
receiveData = null;
}
try{
Thread.sleep(10);
}
catch(InterruptedException e){
//System.out.println("\nInterrupted!");
return;
}
}
}
});
collect.start();
while(System.currentTimeMillis()<=futureTime){
//do nothing.
}
clientSocket.close();
collect.interrupt();
int size = nameList.size();
if (size==0){
System.out.println("No online servers.");
}
else{
for(int i = 0; i< nameList.size();i++){
System.out.println(nameList.get(i)+ ": "+ ipList.get(i));
}
}
}
public static void main(String[] args){
FindUsers f = new FindUsers();
}
}
import java.io.*;
导入java.net。*;
导入java.util.List;
导入java.util.ArrayList;
公共类查找器{
InetAddress InetAddress;
List ipList=新建ArrayList();
列表名称列表=新的ArrayList();
字符串地址;
字符串名;
DatagramSocket客户端套接字;
数据包接收数据包;
整数计数=0;
字节[]接收数据;
未来时间长;
线程收集;
布尔刷新=真;
公共金融机构(){
futureTime=System.currentTimeMillis()+1100;
试一试{
clientSocket=newdatagramsocket(9877);
}
捕获(IOE异常){
e、 printStackTrace();
System.out.println(例如toString());
}
collect=new线程(new Runnable(){
公开募捐{
对于(;;){
receiveData=新字节[15];
receivePacket=新数据包(receiveData,receiveData.length);
试一试{
clientSocket.receive(receivePacket);
inetAddress=receivePacket.getAddress();
ipAddress=inetAddress.getHostAddress();
}
捕获(IOE异常){
//e、 printStackTrace();
}
如果(!ipList.contains(ipAddress)){
name=新字符串(receivePacket.getData());
ipList.add(ipAddress);
姓名列表。添加(姓名);
receiveData=null;
}
试一试{
睡眠(10);
}
捕捉(中断异常e){
//System.out.println(“\nInterrupted!”);
返回;
}
}
}
});
collect.start();
while(System.currentTimeMillis())您真的不应该直接捕获异常。除非我使用另一个循环,如:while(serverIsOpen){…}
因此,当您将其设置为false时,线程将退出。这是我的旧代码和短代码。我知道异常功能。请忽略它,如果有,请给我解决方案。@rekireMore或更少您的代码就可以了。我只会改进它,为服务器搜索添加一个超时。我不确定您的调用是否真的会阻塞(但我认为是这样)如果只有一台服务器,则需要10秒钟才能看到服务器。这可以用更好的方法完成。