JAVA网络编程一题，分全给，谢谢，急。

我给你一个吧，写得比较简单，再实现什么功能，自己修改吧
server
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import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class TestServer {

public static void main(String[] args) throws IOException {

ServerSocket server = new ServerSocket(9999);
while(true) {
Socket s = server.accept();
InputStream in = s.getInputStream();
DataInputStream dis = new DataInputStream(in);
int a = dis.readInt();
int b = dis.readInt();
int sum = a+b;

OutputStream os = s.getOutputStream();
DataOutputStream dos = new DataOutputStream(os);
dos.writeInt(sum);
dos.flush();
s.close();

}
}

}
=====
client

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import java.io.DataInputS