exec（）php总是返回数组（size = 0）为空吗？

Question

I'm trying to execute jar file in my php program. I'm testing with this simple example :

exec('java -jar "C:\wamp\www\Hello.jar" myName', $output);
var_dump($output);

but it always printing

array (size=0)
  empty

BTW the jar file does System.out.println("hello "+args[0]); and I'm testing it in cmd and it is working fine.

Please help I'm struggling with this problem since two days.

Answer 1

try this:

exec('java -jar \"C:\wamp\www\Hello.jar" myName', $output);

instead of

exec('java -jar "C:\wamp\www\Hello.jar" myName', $output);

Answer 2

尝试

exec("/path_to_java -jar C:\wamp\www\Hello.jar myName", $output); 

Answer 3

1. You have to escape backslashes: replace \\ with \\\\
2. You should build CMD and JAR strings separately. (Good programming)
3. Redirect errors to output with 2>&1 to display errors in output.

Simple:

$JAR = 'C:\\wamp\\www\\Hello.jar';
$CMD = sprintf(
    'java -Xmx32m -jar %s myName 2>&1'
    ,escapeshellarg($JAR)
);
exec($CMD, $Output, $Status);
var_dump($CMD, $Output, $Status);