I'm trying to develop a client-server exchange program, and when I try to send data from client to server, I'm running into a SocketException. I've looked at other answers but none of them fit my exact case; I have two calls to osw.write, and only one of them works.
Client:
package me.primesearch.client;
import java.math.BigInteger;
import java.net.*;
import java.io.*;
public class PrimeSearchClient {
public static void main(String[] args) throws IOException{
Socket connection = null;
try{
/** Define a host server */
String host = "localhost";
/** Define a port */
int port = 25564;
StringBuffer instr = new StringBuffer();
System.out.println("SocketClient initialized");
/** Obtain an address object of the server */
InetAddress address = InetAddress.getByName(host);
/** Establish a socket connetion */
connection = new Socket(address, port);
/** Instantiate a BufferedOutputStream object */
BufferedOutputStream bos = new BufferedOutputStream(connection.
getOutputStream());
/** Instantiate a BufferedInputStream object for reading
/** Instantiate a BufferedInputStream object for reading
* incoming socket streams.
*/
BufferedInputStream bis = new BufferedInputStream(connection.
getInputStream());
/**Instantiate an InputStreamReader with the optional
* character encoding.
*/
InputStreamReader isr = new InputStreamReader(bis, "US-ASCII");
/**Read the socket's InputStream and append to a StringBuffer */
int c;
/** Instantiate an OutputStreamWriter object with the optional character
* encoding.
*/
OutputStreamWriter osw = new OutputStreamWriter(bos, "US-ASCII");
while(true){
String process = "drq " + (char) 13;
/** Write across the socket connection and flush the buffer */
osw.write(process);
osw.flush();
while ( (c = isr.read()) != 13)
instr.append( (char) c);
for(int i=0;i<50;i++){
BigInteger offset=new BigInteger(instr.toString()).add(BigInteger.valueOf(i));
if(isProbablyPrime(offset)){
process = "pri" + " " + offset + " " + (offset.divide(new BigInteger("50"))).toString() + (char) 13;
System.out.println(process);
/** Write across the socket connection and flush the buffer */
osw.write(process); //This doesn't work
osw.flush();
System.out.println("Prime found at " + offset);
}
}
}
} catch(IOException e) {
e.printStackTrace();
} finally {
connection.close();
}
}
public static boolean isProbablyPrime(BigInteger n) {
if(n.longValue()!=0){
BigInteger lessOne = n.subtract(BigInteger.ONE);
// get the next prime from one less than number and check with the number
return lessOne.nextProbablePrime().compareTo(n) == 0;
}
return false;
}
}
Server:
package me.primesearch.server;
import java.net.*;
import java.io.*;
public class PrimeSearchServer implements Runnable {
private Socket connection;
@SuppressWarnings("unused")
private int ID;
PrimeSearchServer(Socket s, int i) {
this.connection = s;
this.ID = i;
}
@SuppressWarnings("resource")
public static void main(String[] args) {
int port = 25564;
int count = 0;
try{
ServerSocket socket1 = new ServerSocket(port);
System.out.println("MultipleSocketServer Initialized");
while (true) {
Socket connection = socket1.accept();
Runnable runnable = new PrimeSearchServer(connection, ++count);
Thread thread = new Thread(runnable);
thread.start();
}
}
catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void run() {
try {
BufferedInputStream is = new BufferedInputStream(connection.getInputStream());
InputStreamReader isr = new InputStreamReader(is);
int character;
StringBuffer process = new StringBuffer();
while((character = isr.read()) != 13) {
process.append((char)character);
}
System.out.println(process);
String returnCode="0";
if(process.toString().split(" ")[0].equals("drq")){
System.out.println("Job request recieved");
File file = new File("packages.txt");
//Process input
try (BufferedReader br = new BufferedReader(new FileReader(file))) {
String line;
String prevLine="";
boolean i = false;
int count=0;
while ((line = br.readLine()) != null) {
System.out.println("Looking for a package to send");
// process the line.
if(line.equals("0")){
System.out.println("Sending package " + count);
returnCode = Integer.toString(count);
i = true;
break;
}
prevLine = line;
count++;
System.out.println("No packages found");
}
if(!i){
returnCode = prevLine;
try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("packages.txt", true)))) {
System.out.println("Creating new package");
out.println("0");
returnCode=Integer.toString(count);
}catch (IOException e) {
e.printStackTrace();
}
}
}
} else if (process.toString().split(" ")[0].equals("pri")){
System.out.println("Prime request recieved");
try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("primes.txt", true)))) {
out.println(Integer.parseInt(process.toString().split(" ")[1]));
}catch (IOException e) {
e.printStackTrace();
}
updateLine(Integer.parseInt(process.toString().split(" ")[2]));
}
BufferedOutputStream os = new BufferedOutputStream(connection.getOutputStream());
OutputStreamWriter osw = new OutputStreamWriter(os, "US-ASCII");
osw.write(returnCode + (char)13);
osw.flush();
process = new StringBuffer();
}
catch (Exception e) {
System.out.println(e);
}
finally {
try {
connection.close();
}
catch (IOException e){
e.printStackTrace();
}
}
}
private void updateLine(int lines) throws IOException {
String data="packages.txt";
BufferedReader file = new BufferedReader(new FileReader(data));
String input = "";
String line;
for(int i=0;i<lines;i++){
input+=file.readLine()+System.lineSeparator();
}
file.readLine();
while ((line = file.readLine()) != null)
input += line + System.lineSeparator();
FileOutputStream os = new FileOutputStream(data);
os.write(input.getBytes());
file.close();
os.close();
}
}
Sorry if the indenting on the code looks a bit strange, I'm not used to using stack overflow.
