执行视图输出
string Core_View::render( [ boolean $print = bool true ] )
参数列表
参数 类型 描述 默认值 boolean是否直接echo出,true: 是,false: 将执行完结果的HTML返回 bool true 
string public function render($print = true)
{
    if (empty($this->_file))
    {
        throw new Exception(__('You must set the file to use within your view before rendering'));
    }
    // Combine local and global data and capture the output
    $output = View::capture($this->_file, $this->_data);
    if ($print)
    {
        echo $output;
    }
    else
    {
        return $output;
    }
}