/*注意,这里是userfile,$this->upload->do_upload(),这里do_upload默认上传文件的表单名为userfile;
当然也可以使用do_upload($filename),这里的$filename一定要和form_upload()里面的字符串一致.
我在这里范了糊涂,最后看了手册才明白,希望大家注意哦!
*/

代码:

function upload() {
$config['upload_path'] = './uploads/';
/*这里的uploads是相对于index.PHP的,也就是入口文件,这个千万不要弄错哦!
否则就会报错"The upload path does not appear to be valid.";
*/
$config['allowed_types'] = 'gif|jpg|png';
/*我试着去上传其它类型的文件,这里一定要注意顺序!
A problem was encountered while attempting to move the uploaded file to the final destination.
这个错误一般是上传文件的文件名不能是中文名,这个很郁闷!还未解决,大家可以用其它方法,重新改一下文件名就可以解决了!
$config['allowed_types'] = 'zip|gz|png|gif|jpg';(正确)
$config['allowed_types'] = 'png|gif|jpg|zip|gz';(错误)
*/
$config['max_size'] = '1024';
$config['max_width'] = '1024';
$config['max_height'] = '768';

$config['file_name'] = time(); //文件名不使用原始名
$this->load->library('upload',$config);
if(!$this->upload->do_upload()) {
echo $this->upload->display_errors();
}else{

$data['upload_data']=$this->upload->data(); //文件的一些信息
$img=$data['upload_data']['file_name']; //取得文件名

echo $img."
";

foreach($data['upload_data'] as $item => $value){
echo $item.":".$value."
";

}

}
}