缓存无法正常工作

Question

I am using the cache concept first time in codeigniter.I just followed the guidelines specified in codeigniter tutorials.But cache is not clearing after the time specified.Code is as follows:

$this->load->driver('cache');
if ( ! $foo = $this->cache->get('foo'))
{
 echo 'Saving to the cache!<br />';
 $foo = 'foobarbaz!';
 $this->cache->save('foo', $foo, 120);
}

echo $foo; 

After two minutes what will be the value of $foo? Whether i have to do any other settings?

Answer 1

$cache = $this->cache->get('cache_data');
if ($cache) {
   echo $data = $this->cache->get('cache_data');
} else {
   echo 'Cache is not set';
   $this->cache->save('cache_data','data',3600);
}

I tried this code also.But every time it will execute the else part.

Answer 2

if ( ! $data = $this->cache->get('cache_data'))
{
     $data = array();// your data
     $this->cache->save('cache_data', $data, 600000);
}