PHP实现文件上传和下载的示例代码

1.效果图

2.首先是封装好的图片类（缩放及生成水印）

1.GDBasic.php

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<?php /**   * GDBasic.php   * description GD基础类   */   namespace test\Lib;     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 ;      } }

2.Image.php

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<?php /**   * Image.php   * description 图像类   */   namespace test\Lib;   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

3.ajax类封装文件

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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);      } };

1.index.php

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<!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 = "external nofollow"  rel = "stylesheet" >      < link href = "style/css/site.min.css" rel = "external nofollow"  rel = "stylesheet" >      < link rel = "stylesheet" href = "https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css" rel = "external nofollow" >      < 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 = " rel=" external nofollow" _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 = " rel=" external nofollow"  rel = "external nofollow" _blank"></ a >                      </ li >                      < li >                          < a href = "" target = " rel=" external nofollow"  rel = "external nofollow" _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" style = "text-align:center" >              < ul 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" rel = "external nofollow"  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 style = "text-align:center" >< i class = "fa fa-spinner fa-spin" style = "font-size:24px" ></ i > 加载中...</ p >';              $.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 + '" rel = "external nofollow"  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) + ');" rel = "external nofollow"  rel = "external nofollow" >Previous</ a ></ li >';                      } else {                          previousBtn = '< li class = "page-item" >< a class = "page-link" href = "javascript:requestPage(' + (res.page_number - 1) + ');" rel = "external nofollow"  rel = "external nofollow" >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) + ');" rel = "external nofollow"  rel = "external nofollow" >Next</ a ></ li >';                      } else {                          nextBtn = '< li class = "page-item" >< a class = "page-link" href = "javascript:requestPage(' + (res.page_number + 1) + ');" rel = "external nofollow"  rel = "external nofollow" >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 + ');" rel = "external nofollow" >' + page + '</ a ></ li >';                      }                      pages += nextBtn;                      pagination.innerHTML = pages;                  }                },'json');          };          requestData(1, ''); </ script > </ body > </ html >

2.图片相关功能处理

upload_class.php

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<?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 \test\Lib\Image( $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(); }

3.封装好的文件上传类

UploadFile.php

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<?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;      }   }

4.搜索功能实现

search.php

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<?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 );

4.最后数据库格式 

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/* 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' ,

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原文链接：https://mp.weixin.qq.com/s/xa62IMg7Uom0BPL8IoFeLA