<?php
$conn = mysqli_connect("localhost","root","root","world");
if(empty($_GET['id'])){
$result = $conn->query("SELECT id, length(data) FROM files LIMIT 20");
if($result->num_rows == 0){
print "No images!\n";
print "<a href=\"index3.php\">Click here to add one</a>\n";
exit();
}
while($row = $result->fetch_row()){
print "<a href=\"$_SERVER[PHP_SELF]?id=$row[0]\">";
print "image $row[0] ($row[1] bytes)</a><br />\n";
}
exit();
}
$stmt = $conn->prepare("SELECT data FROM files WHERE id = ?");
$stmt->bind_param("i", $_GET['id']);
$stmt->execute();
$data = null;
$stmt->bind_result($data);
if(!$stmt->fetch()){
die("No such image");
}
header("Content-type: image/jpeg");
print $data;
运行效果:
![](https://img-blog.csdnimg.cn/20200508022216970.jpg)
点击链接后:
![](https://img-blog.csdnimg.cn/20200508022338460.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2VzYW53ZWI=,size_16,color_FFFFFF,t_70)
脚本说明:刚加载时没有GET传参,也就是empty($_GET['id'])==true,程序会把文件数据表中的数据列表显示出来,包括ID和字节数,字节数是通过SQL语句中的length(data)获取的.有可能数据库中没有一条记录,这时会提示增加一条,然后exit(),程序就不会向下执行了.
如有$_GET['id']有值,则构造SQL语句,绑定BLOB字段内容到$data变量,由于是$data不是普通文本,所以还要设置对应的MIME类型,这里是jpg图片,所以用header("Content-type: image/jpeg");告诉浏览器,要以图片的形式来接收字节码.