在使用php codeigniter和pdf2text解析包含unicode字符串的pdf之后，它给出了空白结果

This is my controller function where i am extracting the pdf2text with class and storing it in database, as this function is not displaying any result it is giving blank page in the browser.

public function extract_text_trial()
        {
                    $path=base_url("upload/".$file);                
                    $a = new PDF2Text();
                    $a->setFilename($path); 
                    $a->decodePDF();
                    $s=$a->output();

                    $n=stristr($s,'District:');
                    $n1 = explode("
",$n);
                    $Dist= $n1[0];
                    print "$Dist";

                    $n=stristr($s,'Type of Information:');
                    $n1 = explode("
", $n);
                    $TOI= $n1[0];
                    print "$TOI";

                    $this->load->model('Uploadm');
            //store the extracted texts in the database
                    $data =$this->Uploadm-  >save_fir($District,$TypeofInformation);
                    $data['query']=$this->Uploadm->view_data();
                    $this->load->view('Uploadview',$data);
            }