Java 我有两个android应用程序,一个可以在特定IP通过LAN发送字符串,另一个用于接收,但我想通过LAN广播字符串?
我想通过LAN广播字符串,但当我将客户端代码中的服务器IP更改为255.255.255.255时,它不会广播。为了通过LAN广播字符串,我应该做什么?我应该在客户端代码中做些什么,以便不同IP上的所有侦听端口可以同时接收字符串 我的客户端或发送字符串的代码是:Java 我有两个android应用程序,一个可以在特定IP通过LAN发送字符串,另一个用于接收,但我想通过LAN广播字符串?,java,android,sockets,udp,udpclient,Java,Android,Sockets,Udp,Udpclient,我想通过LAN广播字符串,但当我将客户端代码中的服务器IP更改为255.255.255.255时,它不会广播。为了通过LAN广播字符串,我应该做什么?我应该在客户端代码中做些什么,以便不同IP上的所有侦听端口可以同时接收字符串 我的客户端或发送字符串的代码是: public class MainActivity extends Activity { private Socket socket; private static final int SERVERPORT = 6000
public class MainActivity extends Activity {
private Socket socket;
private static final int SERVERPORT = 6000;
private static final String SERVER_IP = "192.168.1.10";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Thread(new ClientThread()).start();
}
public void onClick(View view) {
try {
EditText et = (EditText) findViewById(R.id.EditText01);
String str = et.getText().toString();
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
out.println(str);
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
class ClientThread implements Runnable {
@Override
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
socket = new Socket(serverAddr, SERVERPORT);
} catch (UnknownHostException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
}
public class MainActivity extends Activity {
private ServerSocket serverSocket;
Handler updateConversationHandler;
Thread serverThread = null;
private TextView text;
public static final int SERVERPORT = 6000;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text = (TextView) findViewById(R.id.text2);
updateConversationHandler = new Handler();
this.serverThread = new Thread(new ServerThread());
this.serverThread.start();
}
@Override
protected void onStop() {
super.onStop();
try {
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
class ServerThread implements Runnable {
public void run() {
Socket socket = null;
try {
serverSocket = new ServerSocket(SERVERPORT);
} catch (IOException e) {
e.printStackTrace();
}
while (!Thread.currentThread().isInterrupted()) {
try {
socket = serverSocket.accept();
CommunicationThread commThread = new CommunicationThread(socket);
new Thread(commThread).start();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class CommunicationThread implements Runnable {
private Socket clientSocket;
private BufferedReader input;
public CommunicationThread(Socket clientSocket) {
this.clientSocket = clientSocket;
try {
this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
while (!Thread.currentThread().isInterrupted()) {
try {
String read = input.readLine();
updateConversationHandler.post(new updateUIThread(read));
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class updateUIThread implements Runnable {
private String msg;
public updateUIThread(String str) {
this.msg = str;
}
@Override
public void run() {
text.setText(text.getText().toString()+"Client Says: "+ msg + "\n");
}
}
}
我的服务器或接收字符串的代码是:
public class MainActivity extends Activity {
private Socket socket;
private static final int SERVERPORT = 6000;
private static final String SERVER_IP = "192.168.1.10";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Thread(new ClientThread()).start();
}
public void onClick(View view) {
try {
EditText et = (EditText) findViewById(R.id.EditText01);
String str = et.getText().toString();
PrintWriter out = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())), true);
out.println(str);
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
class ClientThread implements Runnable {
@Override
public void run() {
try {
InetAddress serverAddr = InetAddress.getByName(SERVER_IP);
socket = new Socket(serverAddr, SERVERPORT);
} catch (UnknownHostException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}
}
public class MainActivity extends Activity {
private ServerSocket serverSocket;
Handler updateConversationHandler;
Thread serverThread = null;
private TextView text;
public static final int SERVERPORT = 6000;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text = (TextView) findViewById(R.id.text2);
updateConversationHandler = new Handler();
this.serverThread = new Thread(new ServerThread());
this.serverThread.start();
}
@Override
protected void onStop() {
super.onStop();
try {
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
class ServerThread implements Runnable {
public void run() {
Socket socket = null;
try {
serverSocket = new ServerSocket(SERVERPORT);
} catch (IOException e) {
e.printStackTrace();
}
while (!Thread.currentThread().isInterrupted()) {
try {
socket = serverSocket.accept();
CommunicationThread commThread = new CommunicationThread(socket);
new Thread(commThread).start();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class CommunicationThread implements Runnable {
private Socket clientSocket;
private BufferedReader input;
public CommunicationThread(Socket clientSocket) {
this.clientSocket = clientSocket;
try {
this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
while (!Thread.currentThread().isInterrupted()) {
try {
String read = input.readLine();
updateConversationHandler.post(new updateUIThread(read));
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class updateUIThread implements Runnable {
private String msg;
public updateUIThread(String str) {
this.msg = str;
}
@Override
public void run() {
text.setText(text.getText().toString()+"Client Says: "+ msg + "\n");
}
}
}
Socket
是TCP套接字。使用TCP无法进行广播。如果要使用TCP,则不能进行广播,必须为每个客户端打开一个连接,并通过每个连接分别发送数据
DatagramSocket
是一个UDP套接字。可以使用UDP进行广播。但是,需要注意的是,UDP不能保证您的消息实际到达。为了保证消息到达,您必须实现某种确认/重试协议,但如果这样做,您还可以使用TCP,因为它就是这样做的
编辑:下面评论中的另一个问题和我的回答。OP写道:
那么,我将如何获得局域网中监听设备的IP,以便单独建立连接
这里的主题是设备或服务发现,这是一个常见的挑战。有很多选择。以下是一些,没有特定顺序:
选项6以极低的发现性能和潜在的高系统资源利用率为代价,避免了手动配置。选项3-5寻求优化发现过程。您说过“您必须为每个客户端打开一个连接,并通过每个连接分别发送数据”,那么我将如何获得LAN中侦听设备的IP以便分别建立连接@Jason CI已将我对您评论的回答整合到上述答案中,并在此处删除了我的评论。