php做图片上传功能

小灰灰 2021-09-16 14:48 462阅读 0赞

今天来做一个图片上传功能的插件，首先做一个html文件：text.php

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>无标题文档</title>
    </head>
    
    <body>
    <h1>文件上传</h1>
    <div id="divPreview">
            <img id="imgHeadPhoto" src="noperson.jpg" style="width: 160px; height: 170px; border: solid 1px #d2e2e2;"
                alt="" />
    </div>
    
    <form action="upload.php" method="post" enctype="multipart/form-data">
    
        <input type="file" name="file" onchange="PreviewImage(this,'imgHeadPhoto','divPreview');" size="20" />
        <input  type="submit" value="上传"/>
    
    </form>
    </body>
    <script type="text/javascript">
            //js本地图片预览，兼容ie[6-9]、火狐、Chrome17+、Opera11+、Maxthon3
            function PreviewImage(fileObj, imgPreviewId, divPreviewId) {
                var allowExtention = ".jpg,.bmp,.gif,.png"; //允许上传文件的后缀名document.getElementById("hfAllowPicSuffix").value;
                var extention = fileObj.value.substring(fileObj.value.lastIndexOf(".") + 1).toLowerCase();
                var browserVersion = window.navigator.userAgent.toUpperCase();
                if (allowExtention.indexOf(extention) > -1) {
                    if (fileObj.files) {//HTML5实现预览，兼容chrome、火狐7+等
                        if (window.FileReader) {
                            var reader = new FileReader();
                            reader.onload = function (e) {
                                document.getElementById(imgPreviewId).setAttribute("src", e.target.result);
                            }
                            reader.readAsDataURL(fileObj.files[0]);
                        } else if (browserVersion.indexOf("SAFARI") > -1) {
                            alert("不支持Safari6.0以下浏览器的图片预览!");
                        }
                    } else if (browserVersion.indexOf("MSIE") > -1) {
                        if (browserVersion.indexOf("MSIE 6") > -1) {//ie6
                            document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
                        } else {//ie[7-9]
                            fileObj.select();
                            if (browserVersion.indexOf("MSIE 9") > -1)
                                fileObj.blur(); //不加上document.selection.createRange().text在ie9会拒绝访问
                            var newPreview = document.getElementById(divPreviewId + "New");
                            if (newPreview == null) {
                                newPreview = document.createElement("div");
                                newPreview.setAttribute("id", divPreviewId + "New");
                                newPreview.style.width = document.getElementById(imgPreviewId).width + "px";
                                newPreview.style.height = document.getElementById(imgPreviewId).height + "px";
                                newPreview.style.border = "solid 1px #d2e2e2";
                            }
                            newPreview.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale',src='" + document.selection.createRange().text + "')";
                            var tempDivPreview = document.getElementById(divPreviewId);
                            tempDivPreview.parentNode.insertBefore(newPreview, tempDivPreview);
                            tempDivPreview.style.display = "none";
                        }
                    } else if (browserVersion.indexOf("FIREFOX") > -1) {//firefox
                        var firefoxVersion = parseFloat(browserVersion.toLowerCase().match(/firefox\/([\d.]+)/)[1]);
                        if (firefoxVersion < 7) {//firefox7以下版本
                            document.getElementById(imgPreviewId).setAttribute("src", fileObj.files[0].getAsDataURL());
                        } else {//firefox7.0+                    
                            document.getElementById(imgPreviewId).setAttribute("src", window.URL.createObjectURL(fileObj.files[0]));
                        }
                    } else {
                        document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
                    }
                } else {
                    alert("仅支持" + allowExtention + "为后缀名的文件!");
                    fileObj.value = ""; //清空选中文件
                    if (browserVersion.indexOf("MSIE") > -1) {
                        fileObj.select();
                        document.selection.clear();
                    }
                    fileObj.outerHTML = fileObj.outerHTML;
                }
                return fileObj.value;    //返回路径
            }
        </script>
    </html>

做完后的效果：

![format_png][]

这样可以点击浏览选择图片，然后上传，现在我们再做怎样把选择的图片传到我们新建的img文件里来，在做一个php处理页面：upload.php

<?php
    //var_dump($_FILES["file"]);
    //array(5) { ["name"]=> string(17) "56e79ea2e1418.jpg" ["type"]=> string(10) "image/jpeg" ["tmp_name"]=> string(43) "C:\Users\asus\AppData\Local\Temp\phpD07.tmp" ["error"]=> int(0) ["size"]=> int(454445) } 
    //1.限制文件的类型，防止注入php或其他文件，提升安全
    //2.限制文件的大小，减少内存压力
    //3.防止文件名重复，提升用户体验
        //方法一：  修改文件名    一般为:时间戳+随机数+用户名
        // 方法二:建文件夹
        
    //4.保存文件
    
    //判断上传的文件是否出错,是的话，返回错误
    if($_FILES["file"]["error"])
    {
        echo $_FILES["file"]["error"];    
    }
    else
    {
        //没有出错
        //加限制条件
        //判断上传文件类型为png或jpg且大小不超过1024000B
        if(($_FILES["file"]["type"]=="image/png"||$_FILES["file"]["type"]=="image/jpeg")&&$_FILES["file"]["size"]<1024000)
        {
                //防止文件名重复
                $filename ="./img/".time().$_FILES["file"]["name"];
                //转码，把utf-8转成gb2312,返回转换后的字符串， 或者在失败时返回 FALSE。
                $filename =iconv("UTF-8","gb2312",$filename);
                 //检查文件或目录是否存在
                if(file_exists($filename))
                {
                    echo"该文件已存在";
                }
                else
                {  
                    //保存文件,   move_uploaded_file 将上传的文件移动到新位置  
                    move_uploaded_file($_FILES["file"]["tmp_name"],$filename);//将临时地址移动到指定地址    
                }        
        }
        else
        {
            echo"文件类型不对";
        }
    }

现在我们看看效果怎么样：

![format_png 1][]

这个img为空文件，一张图片都没有，现在选择一张图片

![format_png 2][]

![format_png 3][]

第一张，点击选择后，再看看img文件

![format_png 4][]

看看现在上传成功了

[format_png]: /images/20210726/78702fefb7f74c528ee6ee69eabe7251.png
[format_png 1]: /images/20210726/628eee87b74e4bf7aee56a24197dde28.png
[format_png 2]: /images/20210726/802d7443ffb5413fa752a8125739c1e1.png
[format_png 3]: /images/20210726/dad3b3e11c2749f384501c44f4916776.png
[format_png 4]: /images/20210726/ef8749576b96423d9af2a87c151bd018.png