Try reading the file in chunks from Server while writing to client output stream rather than creating a temp byte array and reading entire file into memory. What if requested file is large? Also close the new Socket on server-side in a finally block so socket is closed even if an exception is thrown.
Server Side:
Socket newCon = ss.accept();
FileInputStream is = null;
OutputStream out = null;
try {
InputStream sin = newCon.getInputStream();
DataInputStream sdata = new DataInputStream(sin);
String location = sdata.readUTF();
System.out.println("location=" + location);
File toSend = new File(location);
// TODO: validate file is safe to access here
if (!toSend.exists()) {
System.out.println("File does not exist");
return;
}
is = new FileInputStream(toSend);
out = newCon.getOutputStream();
int bytesRead;
byte[] buffer = new byte[4096];
while ((bytesRead = is.read(buffer)) != -1) {
out.write(buffer, 0, bytesRead);
}
out.flush();
} finally {
if (out != null)
try {
out.close();
} catch(IOException e) {
}
if (is != null)
try {
is.close();
} catch(IOException e) {
}
newCon.close();
}
If you use Apache Common IOUtils library then you can reduce much of the code to read/write files to streams. Here 5-lines down to one line.
org.apache.commons.io.IOUtils.copy(is, out);
Note that having a server that serves files by absolute path to remote clients is potentially dangerous and the target file should be restricted to a given directory and/or set of file types. Don't want to serve out system-level files to unauthenticated clients.