Convert OutputStream data to String

[Amar Naik]

How do i convert a OutputStream data to String. Since OutputStream can only write, i am trouble in converting it to String. Here is my full java code

import java.util.*;
import java.io.*;
import java.net.*;
 

public class jinvoker
{
 
public static int invoke(String program) throws java.io.IOException, java.lang.InterruptedException
{
System.out.println("invoking program: " + program);
Process p = Runtime.getRuntime().exec(program);
int exitValue = p.waitFor();
OutputStream obj = new FileOutputStream("file1.txt");
    obj=p.getOutputStream();
    ByteArrayOutputStream byte1=new ByteArrayOutputStream();
    obj.write(byte1.toByteArray());
    String s=byte1.toString();
    System.out.println("jj: " +s);
return exitValue;
}
 
public static void main(String[] argv)
{
try
{
System.out.println("invoker start");
int retval = invoke("c:\\Program Files\\IBM\\OnDemand for WinNT\\bin\\arsdate -g");
System.out.println("invoker end: returned " + retval);
}
catch(java.io.IOException e)
{
System.out.println("IOException caught: " + e);
}
catch(java.lang.InterruptedException e)
{
System.out.println("InterruptedException caught: " + e);
}
 
}
}    

[David McCombs]

You mean how do I write a String with an OutputStream?

Look at the API docs, you can't only byte[] or int. String does have a method that converts the String to byte[]. However, if you read the FileOutputStream docs it tells you this:

FileOutputStream is meant for writing streams of raw bytes such as image data. For writing streams of characters, consider using FileWriter.

Or you can use ObjectOutputStream and call writeUTF(), but FileWriter is a better option.
[ May 01, 2007: Message edited by: David McCombs ]

[Amar Naik]

Once i get the output Runtime.getRuntime().exec(program), i want to display the output as string.

The "process API" has a method "getOutputStream()" which gives me the output in OutputStream . I want to convert this output to String;

[Campbell Ritchie]

This old article about altering Streams might help.

[Joanne Neal]

A Process's OutputStream is what you use to write data to the Process. If you want to see what the Process is outputting, read the InputStream and ErrorStream

[Paul Clapham]

The getOutputStream() method gets you an OutputStream you can use to write data to the stdin of the Process you created. As such, the idea of converting that to a String doesn't make any sense.

But if your actual goal is to read the data from the stdout of the Process and put it into a String, then the getInputStream() method gets you stdout data. (It is always a good idea to state your actual goal when you post a question, rather than asking how to implement the idea you had to achieve that goal. That way when it turns out your idea is wrong, you have still asked your question.)

Process p = Runtime.getRuntime().exec(...);
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
StringBuffer sb = new StringBuffer();
String line;
while ((line = br.readLine()) != null) {
  sb.append(line).append("\n");
}
String answer = sb.toString();

[ May 01, 2007: Message edited by: Paul Clapham ]

[David McCombs]

Ok, I misunderstood your question. But I think you are misunderstanding what getOutputStream() does. It returns an OutputStream object so you can write to whatever it is connected to. It does not give you the output. You can call toString() but it will not give you any useful information.

An OutputStream is for writing to an underlying process, file, stdout, socket, whatever.

[Amar Naik]

thanks everybody