如何使用shell_exec()函数从php页面执行java命令？

Question

I'm trying to run a Java program from a PHP page, using the function shell_exec(), the problem is that always return an empty response. When run a command like: ls, whoami, which, it works. I think that is related to grant access for the www-data user, but I still can not find a way to do it.

I tried to modify the file /etc/sudoers with the command sudo visudo , for add to the end of the file the next line that suppose to grant access for execute the java command:

www-data ALL=NOPASSWD: /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java

and tried with this too:

www-data ALL=NOPASSWD: /usr/bin/java

I'm using next code to invoke the java command from the php page:

$result = shell_exec('java -version');

echo $result;

I expect the output of the invoked command, but the actual output is empty.

thanks in advance.

Answer 1

Try this code :

exec('java -version '.' 2>&1', $result);
var_dump($result);

Ref: https://medium.com/@jnheo/setting-up-a-web-service-php-to-spit-out-results-from-a-jar-file-213667eb008a

Answer 2

I just tested and it's working

<?php 
    $out = shell_exec('java 2>&1');
    echo '<pre>'.$out.'</pre>';
?> 

Reference : In the shell, what does " 2>&1 " mean?

Answer 3

This might work.

echo shell_exec("echo " . $command_to_exec . " > myfile.java && javac myfile.java && java myfile.java");

executes only one line of java code.