Sending buffered image over socket from client to server - sockets

Question

I am trying to send the images captured from client to server,images are captured using robot class and writing to client socket. In server i am reading the buffered image and writing into server local storage area.I want client capture the screenshots at a regular interval and send to server.server reads the images and stores in its repository.
public class ServerDemo {
public static void main(String[] args) {
try {
ServerSocket serversocket=new ServerSocket(6666);
System.out.println("server listening..........");
while(true)
{
Thread ts=new Thread( new ServerThread(serversocket.accept()));
ts.start();
System.out.println("server thread started.........");
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
ServerThread.java
public class ServerThread implements Runnable {
Socket s;
BufferedImage img = null;
String savelocation="d:\\Screenshot\\";
public ServerThread(Socket server) {
this.s=server;
}
#Override
public void run() {
try {
System.out.println("trying to read Image");
img = ImageIO.read(s.getInputStream());
System.out.println("Image Reading successful.....");
} catch (IOException e) {
System.out.println(e);
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
File save_path=new File(savelocation);
save_path.mkdirs();
try {
ImageIO.write(img, "JPG",new File(savelocation+"img-"+System.currentTimeMillis()+".jpg"));
System.out.println("Image writing successful......");
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println(e);
e.printStackTrace();
}
}
}
ClientDemo.java
public class ClientDemo {
public static void main(String[] args) throws InterruptedException {
try {
Socket client=new Socket("localhost", 6666);
while(true)
{
System.out.println("Hello");
Thread th=new Thread(new ClientThread(client));
th.start();
System.out.println("Thread started........");
th.sleep(1000*60);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
ClientThread.java
public class ClientThread implements Runnable{
Socket c;
public ClientThread(Socket client) {
this.c=client;
}
#Override
public void run() {
try {
System.out.println("client");
//while(true){
Dimension size=Toolkit.getDefaultToolkit().getScreenSize();
Robot robot=new Robot();
BufferedImage img=robot.createScreenCapture(new Rectangle(size));
System.out.println("Going to capture client screen");
ImageIO.write(img, "JPG", c.getOutputStream());
System.out.println("Image capture from client success...!");
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (AWTException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Server Console
server listening..........
server thread started.........
trying to read Image
Image Reading successful.....
Image writing successful......
Client console
Hello
Thread started........
client
Going to capture client screen
Image capture from client success...!
Hello
Thread started........
client
Going to capture client screen
Hello
Thread started........
client
Going to capture client screen
Repeat like this.This code works perfectly for first time after that it fails.Each time runs it capture the images only once.What change i have to make to capture and write the images at regular intervals...Please help me

Answer 1

Try this in ClientDemo.java
while(true)
{
System.out.println("Hello");
Socket client=new Socket("localhost", 6666);
Thread th=new Thread(new ClientThread(client));
th.start();
System.out.println("Thread started........");
th.sleep(1000*60);
}
And make sure that you close the client socket once the thread(ClientThread.java) is completed may be in finally block or at the end of code.

Answer 2

You don't need ImageIO for the server end of this. Just send and receive bytes:
while ((count = in.read(buffer()) > 0)
{
out.write(buffer, 0, count);
}

Answer 3

I see the problem is in the server. The first time it accepts a connection from the client,Thread ts=new Thread( new ServerThread(serversocket.accept())); but the client only connects once Socket client=new Socket("localhost", 6666); When the first transfer is completed the server stay again in the accept waiting for the client to make the connect which never happen again. Therefore either you should issue only one accept and use that socket for every transfer or close both sockets, at the client and server, and make the accept/connect again.