public function test(){
    //创建一个redis对象
    $redis = new \Redis();
    //连接本地的 Redis 服务
    $redis->connect('127.0.0.1', 6379);
    //密码验证,如果没有可以不设置
    $redis->auth('123456');
    //查看服务是否运行
    echo "Server is running: " . $redis->ping();
    echo '<br/>';
    //设置缓存
    $redis->set('username','zhang san',3600);
    //获取缓存
    $user_name = $redis->get('username');
    var_dump($user_name);
  }

'DATA_CACHE_TYPE' => 'Redis'，
'REDIS_HOST' => '127.0.0.1',
'REDIS_PORT' => 6379,

  public function set_info(){
    S('study','123');    
  }
  public function get_info(){
    echo C('DATA_CACHE_TYPE');
    echo '<br/>';
    $a = S('study');
    echo $a;
  }

'REDIS_AUTH' => 123456,

  public function set_info(){
    $a = S('study','1223');
    VAR_dump($a);  //true
  }
  public function get_info(){
    echo C('DATA_CACHE_TYPE'); //Redis
    echo '<br/>';
    $a = S('study');
    echo $a; //1223
  }