如何使用PHP设置$ PATH？

My site is being hosted on a shared server so I don't have su access. I needed to run a piece of code with java but it's not available on the server. So I got a self-extracting version of java and put it on the server in my home directory. Then I gave executable permissions to java and I try running the code. I have to use relative paths when running the file because of the restrictions of the server.

Trying to run the java file ../java/bin/java -jar 'javafile.jar' gives me the following:

error while loading shared libraries: libjli.so: cannot open shared object file: No such file or directory

I looked and libjli.so is located at ../java/lib/i386/jli/libjli.so. So I'm thinking that because I'm running java using a relative path it doesn't exactly know how to look for the other files. I'm hoping that if I can add absolute/path/to/java/bin to $PATH then this issue will be resolved.

So once I'm running my PHP, I can use dirname(__FILE__) to get the full path of my java bin directory. I've tried the following code:

exec('export PATH='.$bin_path.':$PATH', $output, $return);
print_r(array(getenv('PATH'), $output, $return));

Prints:
Array(
  [0] => /usr/local/admin/bin:/usr/local/admin/bin/servers:/sbin:/usr/sbin:/usr/local/sbin:/usr/local/bin:/bin:/usr/bin,
  [1] => Array(),
  [2] => 0
)

So nothing was added to $PATH, no output was given, and the command returned a successful exit value. Is it just the restriction of the server that is preventing me from getting this working?

Firstly, this is not going to work.

exec('export PATH='.$bin_path.':$PATH', $output, $return);

It will launch a child process with a shell, run the export command in the shell, and then the shell will exit. But the export command only changes $PATH for that shell.

I'm not sure, but I suspect that you need to use putenv.

I'm hoping that if I can add absolute/path/to/java/bin to $PATH then this issue will be resolved.

Well, it could only help if you used a simple command name for invoking the java command.

And it would be simpler to just run java using the full absolute pathname; e.g. "/absolute/path/to/java/bin/java"