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Subject:
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how to call an external program?
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Posted By:
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schockp
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Post Date:
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11/12/2003 5:24:45 AM
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I was wondering if it's possible to call an external program? Each time there's a modification in a table, I want to call another program with the modifications made.
Is there any good tutorial about this? Are there any restrictions on calling an external program?
Pieter
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Reply By:
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stratmo
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Reply Date:
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11/13/2003 6:13:10 AM
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hello schockp!
it's popssible. please think of the security drwbacks involved doing this.
please consult
http://asktom.oracle.com/pls/ask/f?p=4950:8:6057230915856871718::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:952229840241,
there is a brief explanation for solving your problem. (sadly it's unix-only (no offence meant here!))
i found an example in my personal archive which also is able to do MS-Windows-calls. I got it out of the internet, but i couldn't find it once more.
/*=========================================*/
/* ProcessRunner.java
* @author: Charles Bell
* @version: June 21, 2001*/
import java.io.*;
/** Executes the String arguments, displays the commands being executed, and displays
* any results.
*/
public class ProcessRunner {
/** Instantiates a class and runs the commands passed in the aguments.
*/
public static void main(String[] args) {
ProcessRunner runner = new ProcessRunner();
String[] command = args;
//{ "exp oli/admin@dbtitan file = olitest.dmp log = olitest.log" };
runner.runCommand(command);
}
/** Runs the commands in a process and displays the results.
*/
public void runCommand(String[] args) {
int number = args.length;
try {
String[] commands;
if (System.getProperty("os.name").compareToIgnoreCase("windows")
> 0) {
commands = new String[number + 2];
commands[0] = "command.com";
//for Windows 95, 98, ME. etc.
if (System.getProperty("os.name").compareToIgnoreCase("nt")
> 0) {
commands[0] = "cmd.exe"; //for Windows NT
}
commands[1] = "/c";
for (int i = 0; i < number; i++) {
commands[i + 2] = args[i];
}
} else {
commands = new String[number];
for (int i = 0; i < number; i++) {
commands[i] = args[i];
}
}
System.out.print("Executing: ");
for (int i = 0; i < commands.length; i++) {
System.out.print(commands[i] + " ");
}
Runtime runtime = Runtime.getRuntime();
Process process = runtime.exec(commands);
// Because some native platforms only provide limited buffer size
// for standard input and output streams, failure to promptly write
// the input stream or read the output stream of the subprocess
// may cause the subprocess to block, and even deadlock.
CheckStream csin = new CheckStream(process.getInputStream());
CheckStream cserr = new CheckStream(process.getErrorStream());
csin.start();
cserr.start();
System.out.print("Waiting for command process to terminate.");
int done = process.waitFor();
process.destroy();
System.out.println("... Done.");
} catch (InterruptedException ie) {
System.out.println("InterruptedException: " + ie.getMessage());
} catch (IOException ioe) {
System.out.println("IOException: " + ioe.getMessage());
}
} /** Inner class for checking the results if any of an InputStream. */
class CheckStream extends Thread {
BufferedReader br;
String lineread = "";
/** Constructor needs an InputStream to form an anonymous
* InputStreamReader which is used to create a BufferedReader
* for reading the stream.
*/
CheckStream(InputStream is) {
this.br = new BufferedReader(new InputStreamReader(is));
}
/** Reads the input stream and displays anything returned.
**/
public void run() {
try {
while ((lineread = br.readLine()) != null) {
System.out.println(lineread);
}
} catch (IOException ioe) {
System.out.println("IOException: " + ioe.getMessage());
}
}
}
}
/*=======================================*/
I hope this helps. wrap this java.method in pl/sql-procedure, grant the privileges needed and it should work.
Bye!
Oli
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Reply By:
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schockp
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Reply Date:
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11/13/2003 6:41:10 AM
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Thank you Oli! As soon as I have some time I'll take a look at it.
Pieter
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