running linux find command through jsp

[Sonal Joshiabc]

Hi Guys,

I am trying to display names of all images in a particular directory (and all its subdirectories) using the below code.

<%
try 
	{
	String cmd = "find /usr/hmt/ -iname *.JPG -printf %f\n";

 if(cmd != null)
 {
 Process child = Runtime.getRuntime().exec(cmd);
 InputStream in = child.getInputStream();
 BufferedReader br = new BufferedReader(new InputStreamReader(in));
 String strLine;
 //Read File Line By Line
 while ((strLine = br.readLine()) != null) {
 // Print the content on the console
 out.print(strLine + "<BR>");

 }
 
in.close();
 try {child.waitFor();}
 catch (InterruptedException e) {e.printStackTrace();}
 } 
}
 catch (IOException e) {System.err.println(e);}
 
 %>

The code is working fine but I am unable to get the image names in separate lines. Please help

Current Output:
abc.jpguntitled.JPGvivek.jpg

Required Output:
abc.jpg
untitled.JPG
vivek.jpg

Also I want to create links to images such that when abc.jpg is clicked, it should open in same window, say in the right half window. Please help.

[Tim Holloway]

Please don't tell me that you want to do this in a professional webapp.

Not only is the practice of putting blocks of executable Java code in JSPs seriously discouraged, the java.io.File class has all the functionality needed to do a "find" operation in write-once/run-anywhere mode (including filtering names) and without the significant overhead of spawning an independent OS process.

As to why your sample is failing, however, I think it's because you're trying to read the command's input stream when you should be trying to read its output stream.

[Sonal Joshiabc]

Hi Tim,

I used locate command to find .jpg files

locate *.jpg

and used processbuilder to execute the command.
it is working now. Thanks for your reply

[Jesper de Jong]

Still, executing a native command in a JSP like this is an ugly, non-portable solution. Tim explained why:

Tim Holloway wrote:Not only is the practice of putting blocks of executable Java code in JSPs seriously discouraged, the java.io.File class has all the functionality needed to do a "find" operation in write-once/run-anywhere mode (including filtering names) and without the significant overhead of spawning an independent OS process.

Your solution is very inefficient, not scalable (when a lot of users use this functionality at the same time, lots of processes will be spawned on the server) and not portable (it will not work if you would have a server running Windows).

You can easily do this in pure Java using methods in the class java.io.File (look it up in the API documentation). That would make your code platform-independent and probably a lot faster.