In general the correct way to run an external program is:
- build you external program command line
- build the ProcessBuilder and Process
- build your own StreamRender
- execute your external program
- check the STDOUT and STDERR of your external program
- verify the exit status of your external program
you can achieve this sequence as described following:
String command = "mysql -u... -p... dbname < file.sql";
ProcessBuilder pb = new ProcessBuilder(command);
Process pr;
try {
pr = pb.start();
StreamRender outputStdout = new StreamRender(pr.getInputStream(), StreamRender.STDOUT);
// your STDOUT output here
outputStdout.start();
StreamRender outputStderr = new StreamRender(pr.getErrorStream(), StreamRender.STDERR);
// your STDERR outpu here
outputStderr.start();
pr.waitFor();
if (pr.exitValue() != 0) {
// your external program fails
} else {
// ok, your external program was executed correctly
}
} catch (Exception e) {
// ...
} finally {
// ...
}
StreamRender.java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
public class StreamRender extends Thread {
public static final String STDOUT = "STDOUT";
public static final String STDERR = "STDERR";
private InputStream inputStream;
private String inputType;
public StreamRender(InputStream inputStream, String inputType) {
this.inputStream = inputStream;
this.inputType = inputType;
}
public void run() {
try {
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader br = new BufferedReader(inputStreamReader);
String line = null;
while ((line = br.readLine()) != null) {
System.out.println(this.inputType + " > " + line);
}
} catch (IOException ioe) {
ioe.printStackTrace();
}
}