文件上传和下载实例源码，分享

效果图

首先是封装好的图片类（缩放及生成水印）

GDBasic.php

<?php /**  * GDBasic.php  * description GD基础类  */  namespace testLib;   class GDBasic {     protected static $_check =false;      //检查服务器环境中gd库     public static function check()     {         //当静态变量不为false         if(static::$_check)         {             return true;         }          //检查gd库是否加载         if(!function_exists("gd_info"))         {             throw new Exception('GD is not exists');         }          //检查gd库版本         $version = '';         $info = gd_info();         if(preg_match("/\d+\.\d+(?:\.\d+)?/", $info["GD Version"], $matches))         {             $version = $matches[0];         }          //当gd库版本小于2.0.1         if(!version_compare($version,'2.0.1','>='))         {             throw new Exception("GD requires GD version '2.0.1' or greater, you have " . $version);         }          self::$_check = true;         return self::$_check;     } }

Image.php

<?php /**  * Image.php  * description 图像类  */  namespace testLib;  require_once 'GDBasic.php';  class Image extends GDBasic {     protected $_width;     protected $_height;     protected $_im;     protected $_type;     protected $_mime;     protected $_real_path;           public function __construct($file)     {         //检查GD库         self::check();         $imageInfo = $this->createImageByFile($file);         $this->_width = $imageInfo['width'];         $this->_height = $imageInfo['height'];         $this->_im = $imageInfo['im'];         $this->_type = $imageInfo['type'];         $this->_real_path = $imageInfo['real_path'];         $this->_mime = $imageInfo['mime'];     }       /**      * 根据文件创建图像      * @param $file      * @return array      * @throws Exception      */     public function createImageByFile($file)     {         //检查文件是否存在         if(!file_exists($file))         {             throw new Exception('file is not exits');         }          //获取图像信息         $imageInfo = getimagesize($file);         $realPath = realpath($file);         if(!$imageInfo)         {             throw new Exception('file is not image file');         }          switch($imageInfo[2])         {             case IMAGETYPE_GIF:                 $im = imagecreatefromgif($file);                 break;             case IMAGETYPE_JPEG:                 $im = imagecreatefromjpeg($file);                 break;             case IMAGETYPE_PNG:                 $im = imagecreatefrompng($file);                 break;             default:                 throw  new Exception('image file must be png,jpeg,gif');         }          return array(             'width'     => $imageInfo[0],             'height'    => $imageInfo[1],             'type'      => $imageInfo[2],             'mime'      => $imageInfo['mime'],             'im'        => $im,             'real_path' => $realPath,         );      }      /**      * 缩略图      * @param  int $width 缩略图高度      * @param  int $height 缩略图宽度      * @return $this      * @throws Exception      */     public function resize($width, $height)     {         if(!is_numeric($width) || !is_numeric($height))         {             throw new Exception('image width or height must be number');         }         //根据传参的宽高获取最终图像的宽高         $srcW = $this->_width;          $srcH = $this->_height;          if($width <= 0 || $height <= 0)         {             $desW = $srcW;//缩略图高度             $desH = $srcH;//缩略图宽度         }         else         {             $srcP = $srcW / $srcH;//宽高比             $desP = $width / $height;               if($width > $srcW)             {                 if($height > $srcH)                 {                     $desW = $srcW;                     $desH = $srcH;                 }                 else                 {                     $desH = $height;                     $desW = round($desH * $srcP);                 }             }             else             {                 if($desP > $srcP)                 {                     $desW = $width;                     $desH = round($desW / $srcP);                 }                 else                 {                     $desH = $height;                     $desW = round($desH * $srcP);                 }             }         }          //PHP版本小于5.5         if(version_compare(PHP_VERSION, '5.5.0', '<'))         {             $desIm = imagecreatetruecolor($desW, $desH);             if(imagecopyresampled($desIm, $this->_im, 0, 0, 0, 0, $desW, $desH, $srcW, $srcH))             {                 imagedestroy($this->_im);                 $this->_im = $desIm;                 $this->_width = imagesx($this->_im);                 $this->_height = imagesy($this->_im);             }         }         else         {             if($desIm = imagescale($this->_im, $desW, $desH))             {                 $this->_im = $desIm;                 $this->_width = imagesx($this->_im);                 $this->_height = imagesy($this->_im);             }          }          return $this;     }       /**      * 根据百分比生成缩略图      * @param int $percent 1-100      * @return Image      * @throws Exception      */     public function resizeByPercent($percent)     {         if(intval($percent) <= 0)         {             throw new Exception('percent must be gt 0');         }          $percent = intval($percent) > 100 ? 100 : intval($percent);          $percent = $percent / 100;          $desW = $this->_width * $percent;         $desH = $this->_height * $percent;         return $this->resize($desW, $desH);     }       /**      * 图像旋转      * @param $degree      * @return $this      */     public function rotate($degree)     {         $degree = 360 - intval($degree);         $back = imagecolorallocatealpha($this->_im,0,0,0,127);         $im = imagerotate($this->_im,$degree,$back,1);         imagesavealpha($im,true);         imagedestroy($this->_im);         $this->_im = $im;         $this->_width = imagesx($this->_im);         $this->_height = imagesy($this->_im);         return $this;     }       /**      * 生成水印      * @param file $water 水印图片      * @param int $pct   透明度      * @return $this      */     public function waterMask($water ='',$pct = 60 )     {         //根据水印图像文件生成图像资源         $waterInfo = $this->createImageByFile($water);         imagecopymerge();         //销毁$this->_im         $this->_im = $waterInfo['im'];         $this->_width = imagesx($this->_im);         $this->_height = imagesy($this->_im);         return $this;      }        /**      * 图片输出      * @return bool      */     public function show()     {         header('Content-Type:' . $this->_mime);         if($this->_type == 1)         {             imagegif($this->_im);             return true;         }          if($this->_type == 2)         {             imagejpeg($this->_im, null, 80);             return true;         }          if($this->_type == 3)         {             imagepng($this->_im);             return true;         }     }      /**      * 保存图像文件      * @param $file      * @param null $quality      * @return bool      * @throws Exception      */     public function save($file, $quality = null)     {         //获取保存目的文件的扩展名         $ext = pathinfo($file, PATHINFO_EXTENSION);         $ext = strtolower($ext);         if(!$ext || !in_array($ext, array('jpg', 'jpeg', 'gif', 'png')))         {             throw new Exception('image save file must be jpg ,png,gif');         }          if($ext === 'gif')         {             imagegif($this->_im, $file);             return true;         }         if($ext === 'jpeg' || $ext === 'jpg')         {             if($quality > 0)             {                 if($quality < 1)                 {                     $quality = 1;                 }                 if($quality > 100)                 {                     $quality = 100;                 }                  imagejpeg($this->_im, $file, $quality);             }             else             {                 imagejpeg($this->_im, $file);             }             return true;         }          if($ext === 'png')         {             imagepng($this->_im, $file);             return true;         }      } }

style样式不是重点，先不放了

然后是ajax类封装的文件 ajax.js

let $ = new class {      constructor()     {         this.xhr = new XMLHttpRequest();         this.xhr.onreadystatechange = () => {             if (this.xhr.readyState == 4 && this.xhr.status == 200) {                 // process response text                 let response = this.xhr.responseText;                 if (this.type == "json") {                     response = JSON.parse(response);                 }                 this.callback(response);             }         }     }      get(url, parameters, callback, type = "text")     {         // url = test.php?username=zhangsan&age=20         // parameters = {"username": "zhangsan", "age": 20}         let data = this.parseParameters(parameters);         if (data.length > 0) {             url += "?" + data;         }         this.type = type;         this.callback = callback;         this.xhr.open("GET", url, true);         this.xhr.send();     }      post(url, parameters, callback, type = "text")     {         let data = this.parseParameters(parameters);         this.type = type;         this.callback = callback;         this.xhr.open("POST", url, true);         this.xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");         this.xhr.send(data);     }      parseParameters(parameters)     {         // username=zhangsan&age=20         let buildStr = "";         for (let key in parameters) {             let str = key + "=" + parameters[key];             buildStr += str + "&";         }         return buildStr.substring(0, buildStr.length - 1);     } };

首页文件index.php

<!DOCTYPE html> <html lang="zh-CN">  <head>     <meta charset="utf-8">     <meta http-equiv="X-UA-Compatible" content="IE=edge">     <meta name="viewport" content="width=device-width, initial-scale=1">     <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->     <title>文件上传和下载</title>     <!-- Bootstrap -->     <link href="style/css/bootstrap.min.css" rel="stylesheet">     <link href="style/css/site.min.css" rel="stylesheet">     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">     <style>         .projects .thumbnail .caption {             height: auto;             max-width: auto;         }         .image{             margin:10px auto;             border-radius:5px;             overflow:hidden;             border:1px solid #CCC;         }         .image .caption P{             text-align: center;         }     </style> </head>  <body>     <!--导航栏-->     <div class="navbar navbar-inverse navbar-fixed-top">         <div class="container">             <div class="navbar-header">                 <button class="navbar-toggle collapsed" type="button" data-toggle="collapse" data-target=".navbar-collapse">                   <span class="sr-only">Toggle navigation</span>                   <span class="icon-bar"></span>                   <span class="icon-bar"></span>                   <span class="icon-bar"></span>                 </button>                 <a class="navbar-brand hidden-sm" href="" onclick="_hmt.push(['_trackEvent', 'navbar', 'click', 'navbar-首页'])">XX网</a>             </div>             <div class="navbar-collapse collapse" role="navigation">                 <ul class="nav navbar-nav">                     <li class="hidden-sm hidden-md">                         <a href="" target="_blank"></a>                     </li>                     <li>                         <a href="" target="_blank"></a>                     </li>                 </ul>             </div>         </div>     </div>     <!--导航栏结束-->     <!--巨幕-->     <div class="jumbotron masthead">         <div class="container">             <h1>文件上传下载</h1>             <h2>实现文件的上传和下载功能</h2>             <p class="masthead-button-links">                 <form class="form-inline" onsubmit="return false;">                     <div class="form-group">                         <input type="search" class="form-control keywords" id="exampleInputName2" placeholder="输入搜索内容" name="keywords" value="">                         <button class="btn btn-default searchBtn" type="submit">搜索</button>                         <button type="button" class="btn btn-primary btn-default" data-toggle="modal" data-target="#myModal">  上传  </button>                     </div>                 </form>             </p>         </div>     </div>     <!--巨幕结束-->     <!-- 模态框 -->     <div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">         <div class="modal-dialog" role="document">             <form class="form-inline" action="upload_class.php" method="post" enctype="multipart/form-data">                 <input type="hidden" name="MAX_FILE_SIZE" value="10240000" />                 <div class="modal-content">                     <div class="modal-header">                         <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>                         <h4 class="modal-title" id="myModalLabel">上传图片</h4>                     </div>                     <div class="modal-body">                         <p>选择图片：</p><input type="file" id="image" name="test_pic[]">                         <br/>                         <p>图片描述：</p><textarea class="form-control" cols="75" name="description" id="info"></textarea>                         <br/><br/>                         <p>                           是否添加水印：                           <select name="mark">                             <option value="1">添加</option>                             <option value="0">不添加</option>                           </select>                         </p>                         <br/>                         <p>                           图片宽度比例：                             <select name="scale">                               <option value="800*600">800*600</option>                               <option value="600*450">600*450</option>                               <option value="400*300">400*300</option>                             </select>                         </p>                     </div>                     <div class="modal-footer">                         <button type="submit" class="btn btn-default" name="submit" id="submit" onclick="show(this)">上传</button>                         <button type="reset" class="btn btn-primary">重置</button>                     </div>                 </div>             </form>         </div>     </div>     <!--模态框结束-->      <div class="container projects">         <div class="projects-header page-header">             <h2>上传图片展示</h2>             <p>将上传的图片展示在页面中</p>         </div>         <div class="row pic_body">             <!-- 使用js显示图片 -->         </div>         <!--分页-->         <nav aria-label="Page navigation">class="pagination pagination-lg">                 <!-- 使用js显示页码 -->             </ul>         </nav>     </div>      <footer class="footer  container">         <div class="row footer-bottom">             <ul class="list-inline text-center">                 <h4><a href="class.test.com" target="_blank">class.test.com</a> | XX网</h4>             </ul>         </div>     </footer>      <!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->     <script src="style/js/jquery.min.js"></script>     <!-- Include all compiled plugins (below), or include individual files as needed -->     <script src="style/js/bootstrap.min.js"></script>     <script type="text/JavaScript">         function show(){           if(document.getElementById("image").value == ''){             alert('请选择图片');           }           if(document.getElementById("info").value == ''){             alert('请输入图片描述');           }         }     </script>     <!-- jQuery first, then Popper.js, then Bootstrap JS -->     <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>     <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>     <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>     <script src="style/js/Ajax.js"></script>     <script>         let pageNo = 1;         let kws = '';         let searchBtn = document.getElementsByClassName('searchBtn')[0];         searchBtn.onclick = function() {             let search = document.getElementsByClassName('keywords')[0];             let keywords = search.value;             requestData(pageNo, keywords);             kws = keywords;         };          let requestPage = function(page) {             requestData(page, kws);             pageNo = page;         };           let requestData = function(page_number, keywords) {             let pagination = document.getElementsByClassName('pagination')[0];             let pic_body = document.getElementsByClassName('pic_body')[0];             pic_body.innerHTML = '<p>class="fa fa-spinner fa-spin">;             $.get('search.php', {"page": page_number, "keywords": keywords}, function (res) {                 let divs = '';                 if (res.code == 1) {                     // 请求成功                     res.rows.forEach(function (item) {                         let div = '<div class="col-sm-6 col-md-3 col-lg-4"><div class="image"><a href="' + item.path + '" target="_blank"><img class="img-responsive" src="' + item.path + '" ></a><div class="caption"><p>' + item.info + '</p></div></div></div>';                         divs += div;                     });                     pic_body.innerHTML = divs;                       // 加载页码导航                     // previous                     let previousBtn = '';                     if (res.page_number == 1) {                         previousBtn = '<li class="page-item disabled"><a class="page-link" href="javascript:requestPage(' + (res.page_number - 1) + ');">Previous</a></li>';                     } else {                         previousBtn = '<li class="page-item"><a class="page-link" href="javascript:requestPage(' + (res.page_number - 1) + ');">Previous</a></li>';                     }                     // next                     let nextBtn = '';                     if (res.page_total == res.page_number) {                         nextBtn = '<li class="page-item disabled"><a class="page-link" href="javascript:requestPage(' + (res.page_number + 1) + ');">Next</a></li>';                     } else {                         nextBtn = '<li class="page-item"><a class="page-link" href="javascript:requestPage(' + (res.page_number + 1) + ');">Next</a></li>'                     }                      let pages = previousBtn;                     for (let page = 1; page <= res.page_total; page++) {                         let active = '';                         if (page == res.page_number) {                             active = 'active';                         }                         pages += '<li class="page-item ' + active + '"><a class="page-link" href="javascript:requestPage(' + page + ');">' + page + '</a></li>';                     }                     pages += nextBtn;                     pagination.innerHTML = pages;                 }                },'json');         };         requestData(1, '');     </script> </body> </html>

图片相关功能处理 upload_class.php

<?php  //接收传过来的数据 $description=$_POST['description'];//描述 $mark=$_POST['mark'];//水印 $scale=$_POST['scale'];//比例 800*600 $path='';//图片存储路径   //根据比例获取宽高 $width=substr($scale,0,3);//800 $height=substr($scale,4,3);//600   //上传图片并存储 require('UploadFile.php');  $upload = new UploadFile('test_pic'); $upload->setDestinationDir('./uploads'); $upload->setAllowMime(['image/jpeg', 'image/gif','image/png']); $upload->setAllowExt(['gif', 'jpeg','jpg','png']); $upload->setAllowSize(2*1024*1024); if ($upload->upload()) {     $filename=$upload->getFileName()[0];     $dir=$upload->getDestinationDir();     $path=$dir.'/'.$filename;//图片存储的实际路径      } else {     var_dump($upload->getErrors()); }   //根据比例调整图像 require_once './lib/Image.php'; $image = new testLibImage($path); //放大并保存 $image->resize($width,$height)->save($path);  $info = getimagesize($path); //根据不同的图像type 来创建图像 switch($info[2]) {     case 1://IMAGETYPE_GIF         $image = imagecreatefromgif($path);         break;     case IMAGETYPE_JPEG:         $image = imagecreatefromjpeg($path);         break;     case 3:         $image = imagecreatefrompng($path);         break;      default:         echo '图像格式不支持';         break;  }      //添加水印 if($mark==1){      $logo=imagecreatefrompng('./uploads/logo.png');     //添加水印     imagecopy($image,$logo,0,0,0,0,imagesx($logo),imagesy($logo));     //header('Content-type:image/png');     imagejpeg($image,$path); }  $dst_image=imagecreatetruecolor($width,$height); //拷贝源图像左上角起始 imagecopy( $dst_image, $image, 0, 0, 0, 0, $width, $height ); imagejpeg($dst_image,$path);  //存入数据库 $servername = "localhost"; $username = "root"; $password = "123456"; $dbname = "pic";  try { $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password); // 设置 PDO 错误模式，用于抛出异常 $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); $sql = "INSERT INTO pic(`path`, `mark`, `scale`,`info`) VALUES ('$path', '$mark', '$scale','$description')"; // 使用 exec() ，没有结果返回 $conn->exec($sql);     exit("<script>alert("图片上传成功!");window.location="index.php";</script>"); } catch(PDOException $e) {     echo $sql . "<br>" . $e->getMessage(); }

封装好的文件上传类 UploadFile.php

<?php /**  * Created by PhpStorm.  * User: JasonLee  * Date: 2018/11/11  * Time: 22:01  */  class UploadFile {      /**      *      */     const UPLOAD_ERROR = [         UPLOAD_ERR_INI_SIZE => '文件大小超出了php.ini当中的upload_max_filesize的值',         UPLOAD_ERR_FORM_SIZE => '文件大小超出了MAX_FILE_SIZE的值',         UPLOAD_ERR_PARTIAL => '文件只有部分被上传',         UPLOAD_ERR_NO_FILE => '没有文件被上传',         UPLOAD_ERR_NO_TMP_DIR => '找不到临时目录',         UPLOAD_ERR_CANT_WRITE => '写入磁盘失败',         UPLOAD_ERR_EXTENSION => '文件上传被扩展阻止',     ];      /**      * @var      */     protected $field_name;      /**      * @var string      */     protected $destination_dir;      /**      * @var array      */     protected $allow_mime;      /**      * @var array      */     protected $allow_ext;      /**      * @var      */     protected $file_org_name;      /**      * @var      */     protected $file_type;      /**      * @var      */     protected $file_tmp_name;      /**      * @var      */     protected $file_error;      /**      * @var      */     protected $file_size;      /**      * @var array      */     protected $errors;      /**      * @var      */     protected $extension;      /**      * @var      */     protected $file_new_name;      /**      * @var float|int      */     protected $allow_size;      /**      * UploadFile constructor.      * @param $keyName      * @param string $destinationDir      * @param array $allowMime      * @param array $allowExt      * @param float|int $allowSize      */     public function __construct($keyName, $destinationDir = './uploads', $allowMime = ['image/jpeg', 'image/gif'], $allowExt = ['gif', 'jpeg'], $allowSize = 2*1024*1024)     {         $this->field_name = $keyName;         $this->destination_dir = $destinationDir;         $this->allow_mime = $allowMime;         $this->allow_ext = $allowExt;         $this->allow_size = $allowSize;     }      /**      * @param $destinationDir      */     public function setDestinationDir($destinationDir)     {         $this->destination_dir = $destinationDir;     }      /**      * @param $allowMime      */     public function setAllowMime($allowMime)     {         $this->allow_mime = $allowMime;     }      /**      * @param $allowExt      */     public function setAllowExt($allowExt)     {         $this->allow_ext = $allowExt;     }      /**      * @param $allowSize      */     public function setAllowSize($allowSize)     {         $this->allow_size = $allowSize;     }      /**      * @return bool      */     public function upload()     {         // 判断是否为多文件上传         $files = [];         if (is_array($_FILES[$this->field_name]['name'])) {             foreach($_FILES[$this->field_name]['name'] as $k => $v) {                 $files[$k]['name'] = $v;                 $files[$k]['type'] = $_FILES[$this->field_name]['type'][$k];                 $files[$k]['tmp_name'] = $_FILES[$this->field_name]['tmp_name'][$k];                 $files[$k]['error'] = $_FILES[$this->field_name]['error'][$k];                 $files[$k]['size'] = $_FILES[$this->field_name]['size'][$k];             }         } else {             $files[] = $_FILES[$this->field_name];         }          foreach($files as $key => $file) {             // 接收$_FILES参数             $this->setFileInfo($key, $file);              // 检查错误             $this->checkError($key);              // 检查MIME类型             $this->checkMime($key);              // 检查扩展名             $this->checkExt($key);              // 检查文件大小             $this->checkSize($key);              // 生成新的文件名称             $this->generateNewName($key);              if (count((array)$this->getError($key)) > 0) {                 continue;             }             // 移动文件             $this->moveFile($key);         }         if (count((array)$this->errors) > 0) {             return false;         }         return true;     }      /**      * @return array      */     public function getErrors()     {         return $this->errors;     }      /**      * @param $key      * @return mixed      */     protected function getError($key)     {         return $this->errors[$key];     }      /**      *      */     protected function setFileInfo($key, $file)     {         // $_FILES  name type temp_name error size         $this->file_org_name[$key] = $file['name'];         $this->file_type[$key] = $file['type'];         $this->file_tmp_name[$key] = $file['tmp_name'];         $this->file_error[$key] = $file['error'];         $this->file_size[$key] = $file['size'];     }       /**      * @param $key      * @param $error      */     protected function setError($key, $error)     {         $this->errors[$key][] = $error;     }       /**      * @param $key      * @return bool      */     protected function checkError($key)     {         if ($this->file_error > UPLOAD_ERR_OK) {             switch($this->file_error) {                 case UPLOAD_ERR_INI_SIZE:                 case UPLOAD_ERR_FORM_SIZE:                 case UPLOAD_ERR_PARTIAL:                 case UPLOAD_ERR_NO_FILE:                 case UPLOAD_ERR_NO_TMP_DIR:                 case UPLOAD_ERR_CANT_WRITE:                 case UPLOAD_ERR_EXTENSION:                     $this->setError($key, self::UPLOAD_ERROR[$this->file_error]);                     return false;             }         }         return true;     }       /**      * @param $key      * @return bool      */     protected function checkMime($key)     {         if (!in_array($this->file_type[$key], $this->allow_mime)) {             $this->setError($key, '文件类型' . $this->file_type[$key] . '不被允许!');             return false;         }         return true;     }       /**      * @param $key      * @return bool      */     protected function checkExt($key)     {         $this->extension[$key] = pathinfo($this->file_org_name[$key], PATHINFO_EXTENSION);         if (!in_array($this->extension[$key], $this->allow_ext)) {             $this->setError($key, '文件扩展名' . $this->extension[$key] . '不被允许！');             return false;         }         return true;     }      /**      * @return bool      */     protected function checkSize($key)     {         if ($this->file_size[$key] > $this->allow_size) {             $this->setError($key, '文件大小' . $this->file_size[$key] . '超出了限定大小' . $this->allow_size);             return false;         }         return true;     }       /**      * @param $key      */     protected function generateNewName($key)     {         $this->file_new_name[$key] = uniqid() . '.' . $this->extension[$key];     }       /**      * @param $key      * @return bool      */     protected function moveFile($key)     {         if (!file_exists($this->destination_dir)) {             mkdir($this->destination_dir, 0777, true);         }         $newName = rtrim($this->destination_dir, '/') . '/' . $this->file_new_name[$key];         if (is_uploaded_file($this->file_tmp_name[$key]) && move_uploaded_file($this->file_tmp_name[$key], $newName)) {             return true;         }         $this->setError($key, '上传失败！');         return false;     }      /**      * @return mixed      */     public function getFileName()     {         return $this->file_new_name;     }      /**      * @return string      */     public function getDestinationDir()     {         return $this->destination_dir;     }      /**      * @return mixed      */     public function getExtension()     {         return $this->extension;     }      /**      * @return mixed      */     public function getFileSize()     {         return $this->file_size;     }  }

搜索功能实现 search.php

<?php  // 接收请求数据 $pageNo = $_GET['page'] ?? 1; $pageSize = 9;  // 接收查询参数 $keywords = $_GET['keywords'] ?? '';  $data = []; //模拟加载中的图标sleep(3); try {     $pdo = new PDO('mysql:host=localhost:3306;dbname=pic',         'root',         '123456',         [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]     );      // 请求mysql 查询记录总数     $sql = 'SELECT count(*) AS aggregate FROM pic';     if (strlen($keywords) > 0) {         $sql .= ' WHERE info like ?';     }     $stmt = $pdo->prepare($sql);     if (strlen($keywords) > 0) {         $stmt->bindValue(1, '%' . $keywords . '%', PDO::PARAM_STR);     }     $stmt->execute();     $total = $stmt->fetch(PDO::FETCH_ASSOC)['aggregate'];          // 计算最大页码，设置页码边界     $minPage = 1;     $maxPage = ceil($total / $pageSize); // 3.6     $pageNo = max($pageNo, $minPage);     $pageNo = min($pageNo, $maxPage);     $offset = ($pageNo - 1) * $pageSize;       $sql="SELECT `path`,`info` FROM pic ";     if (strlen($keywords) > 0) {         $sql .= ' WHERE info like ?';     }     $sql .= 'ORDER BY id DESC LIMIT ?, ?';     $stmt = $pdo->prepare($sql);     if (strlen($keywords) > 0) {         $stmt->bindValue(1, '%' . $keywords . '%', PDO::PARAM_STR);         $stmt->bindValue(2, (int)$offset, PDO::PARAM_INT);         $stmt->bindValue(3, (int)$pageSize, PDO::PARAM_INT);     } else {         $stmt->bindValue(1, (int)$offset, PDO::PARAM_INT);         $stmt->bindValue(2, (int)$pageSize, PDO::PARAM_INT);     }     $stmt->execute();     $results = $stmt->fetchAll(PDO::FETCH_ASSOC);     $data = [         'code' => 1,         'msg' => 'ok',         'rows' => $results,         'total_records' => (int)$total,         'page_number' => (int)$pageNo,         'page_size' => (int)$pageSize,         'page_total' => (int)$maxPage,     ];     } catch (PDOException $e) {     $data = [         'code' => 0,         'msg' => $e->getMessage(),         'rows' => [],         'total_records' => 0,         'page_number' => 0,         'page_size' => (int)$pageSize,         'page_total' => 0,     ]; }  header('Content-type: application/json'); echo json_encode($data);

最后数据库格式 

/* Navicat MySQL Data Transfer  Source Server         : localhost Source Server Version : 80012 Source Host           : localhost:3306 Source Database       : pic  Target Server Type    : MYSQL Target Server Version : 80012 File Encoding         : 65001  Date: 2020-01-14 16:22:49 */  SET FOREIGN_KEY_CHECKS=0;  -- ---------------------------- -- Table structure for pic -- ---------------------------- DROP TABLE IF EXISTS `pic`; CREATE TABLE `pic` (   `id` int(10) unsigned NOT NULL AUTO_INCREMENT,   `path` varchar(255) DEFAULT NULL,   `mark` tinyint(3) DEFAULT NULL,   `scale` varchar(255) DEFAULT NULL,   `info` varchar(255) DEFAULT NULL,   PRIMARY KEY (`id`) ) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;  -- ---------------------------- -- Records of pic -- ---------------------------- INSERT INTO `pic` VALUES ('1', './uploads/5e1d788084cc5.jpg', '1', '800*600', '这是测试图片1'); INSERT INTO `pic` VALUES ('2', './uploads/5e1d789766591.jpg', '1', '600*450', '这是测试图片2');

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