
1. 引言:理解Base64图片显示挑战
在web开发中,有时我们需要将图片数据直接存储在数据库中,而不是作为文件存储在服务器上。base64编码是一种将二进制数据转换为ascii字符串的方法,使其可以在文本环境中传输和存储。当我们将图片以base64格式存储在数据库(例如mysql的longblob类型)中时,一个常见的需求就是通过php脚本将其取出,并在html页面上显示。
然而,开发者在尝试显示这些Base64图片时,经常会遇到图片无法加载、显示为破损图标或空白区域的问题。这通常是由于对Base64图片在HTML 标签 src 属性中的正确格式理解不足,或者在PHP处理过程中进行了不必要的或错误的字符串操作。
2. Base64图片在HTML中的正确格式
要在HTML中直接嵌入Base64编码的图片,需要使用data: URI方案。其基本格式如下:
@@##@@][;base64],">
其中:
- mediatype:图片的MIME类型,例如 image/jpeg、image/png、image/gif 等。
- ;base64:指示数据是Base64编码的。
- :实际的Base64编码图片数据字符串。
一个完整的Base64图片URI示例如下:
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data:image/jpeg;base64,/9j/4AAQSkZJRgABAQEAAAAAAAD/2wBDAAwICQsJCAwLCgsODQwOEh4UEhEREiUaHBYeLCYuLSsmKikwNkU7MDNBNCkqPFI9QUdKTU5NLzpVW1RLWkVMTUr/... (省略大量Base64数据)
关键点: 数据库中存储的Base64图片数据,如果已经是这种带有data:image/...;base64,前缀的完整URI格式,那么在PHP中取出后,可以直接将其作为
摄像头画面
@@##@@' alt="摄像头画面">
%E5%9C%A8%E4%B8%8A%E8%BF%B0%E4%BB%A3%E7%A0%81%E4%B8%AD%EF%BC%8C%E5%85%B3%E9%94%AE%E7%9A%84%E6%94%B9%E5%8F%98%E6%98%AF%EF%BC%9A
- SELECT%20Video%20FROM%20video%EF%BC%9A%E6%98%8E%E7%A1%AE%E5%8F%AA%E9%80%89%E6%8B%A9Video%E5%88%97%EF%BC%8C%E9%81%BF%E5%85%8D%E4%BA%86%E4%B8%8D%E5%BF%85%E8%A6%81%E7%9A%84%E5%88%97%E6%95%B0%E6%8D%AE%E3%80%82
- %24row%20=%20mysqli_fetch_array(%24img_query);%EF%BC%9A%E8%8E%B7%E5%8F%96%E6%9F%A5%E8%AF%A2%E7%BB%93%E6%9E%9C%E3%80%82
- echo%20%24row[0];%EF%BC%9A%E7%9B%B4%E6%8E%A5%E8%BE%93%E5%87%BA%E6%95%B0%E7%BB%84%E4%B8%AD%E7%AC%AC%E4%B8%80%E4%B8%AA%E5%85%83%E7%B4%A0%EF%BC%88%E5%8D%B3Video%E5%88%97%E7%9A%84%E5%80%BC%EF%BC%89%EF%BC%8C%E8%BF%99%E4%B8%AA%E5%80%BC%E5%BA%94%E8%AF%A5%E5%B7%B2%E7%BB%8F%E6%98%AF%E5%AE%8C%E6%95%B4%E7%9A%84Base64%E6%95%B0%E6%8D%AEURI%E3%80%82
5.%20%E6%B3%A8%E6%84%8F%E4%BA%8B%E9%A1%B9%E4%B8%8E%E6%9C%80%E4%BD%B3%E5%AE%9E%E8%B7%B5
- %E6%95%B0%E6%8D%AE%E5%BA%93%E5%AD%97%E6%AE%B5%E7%B1%BB%E5%9E%8B%EF%BC%9A%20%E5%AD%98%E5%82%A8Base64%E7%BC%96%E7%A0%81%E5%9B%BE%E7%89%87%E6%95%B0%E6%8D%AE%E6%97%B6%EF%BC%8C%E5%BA%94%E4%BD%BF%E7%94%A8LONGBLOB%E6%88%96LONGTEXT%E7%B1%BB%E5%9E%8B%E3%80%82LONGBLOB%E9%80%82%E7%94%A8%E4%BA%8E%E4%BA%8C%E8%BF%9B%E5%88%B6%E6%95%B0%E6%8D%AE%EF%BC%8C%E8%80%8CLONGTEXT%E9%80%82%E7%94%A8%E4%BA%8E%E9%9D%9E%E5%B8%B8%E9%95%BF%E7%9A%84%E6%96%87%E6%9C%AC%E5%AD%97%E7%AC%A6%E4%B8%B2%E3%80%82%E7%94%B1%E4%BA%8EBase64%E7%BC%96%E7%A0%81%E5%90%8E%E7%9A%84%E6%95%B0%E6%8D%AE%E6%9C%AC%E8%B4%A8%E4%B8%8A%E6%98%AF%E5%AD%97%E7%AC%A6%E4%B8%B2%EF%BC%8CLONGTEXT%E9%80%9A%E5%B8%B8%E6%9B%B4%E5%90%88%E9%80%82%EF%BC%8C%E4%BD%86LONGBLOB%E4%B9%9F%E8%83%BD%E5%85%BC%E5%AE%B9%E5%AD%98%E5%82%A8%E3%80%82
- %E6%80%A7%E8%83%BD%E8%80%83%E9%87%8F%EF%BC%9A%20%E7%9B%B4%E6%8E%A5%E5%9C%A8HTML%E4%B8%AD%E5%B5%8C%E5%85%A5Base64%E5%9B%BE%E7%89%87%E4%BC%9A%E5%A2%9E%E5%8A%A0HTML%E6%96%87%E4%BB%B6%E7%9A%84%E5%A4%A7%E5%B0%8F%E3%80%82%E5%AF%B9%E4%BA%8E%E5%B0%91%E9%87%8F%E3%80%81%E8%BE%83%E5%B0%8F%E7%9A%84%E5%9B%BE%E7%89%87%EF%BC%8C%E8%BF%99%E7%A7%8D%E6%96%B9%E6%B3%95%E5%BE%88%E6%96%B9%E4%BE%BF%E3%80%82%E4%BD%86%E5%AF%B9%E4%BA%8E%E5%A4%A7%E9%87%8F%E6%88%96%E5%A4%A7%E5%B0%BA%E5%AF%B8%E5%9B%BE%E7%89%87%EF%BC%8C%E8%BF%99%E4%BC%9A%E6%98%BE%E8%91%97%E5%A2%9E%E5%8A%A0%E9%A1%B5%E9%9D%A2%E5%8A%A0%E8%BD%BD%E6%97%B6%E9%97%B4%E3%80%82%E5%9C%A8%E8%BF%99%E7%A7%8D%E6%83%85%E5%86%B5%E4%B8%8B%EF%BC%8C%E6%9B%B4%E5%A5%BD%E7%9A%84%E5%81%9A%E6%B3%95%E6%98%AF%E5%B0%86%E5%9B%BE%E7%89%87%E5%AD%98%E5%82%A8%E4%B8%BA%E6%96%87%E4%BB%B6%EF%BC%8C%E5%B9%B6%E5%9C%A8%E6%95%B0%E6%8D%AE%E5%BA%93%E4%B8%AD%E5%AD%98%E5%82%A8%E6%96%87%E4%BB%B6%E7%9A%84%E8%B7%AF%E5%BE%84%EF%BC%8C%E7%84%B6%E5%90%8E%E9%80%9A%E8%BF%87%E5%B8%B8%E8%A7%84%E7%9A%84
%E6%A0%87%E7%AD%BE%E5%BC%95%E7%94%A8%E5%9B%BE%E7%89%87URL%E3%80%82
- MIME%E7%B1%BB%E5%9E%8B%E5%8C%B9%E9%85%8D%EF%BC%9A%20%E7%A1%AE%E4%BF%9Ddata:%20URI%E4%B8%AD%E7%9A%84MIME%E7%B1%BB%E5%9E%8B%EF%BC%88%E4%BE%8B%E5%A6%82image/jpeg%EF%BC%89%E4%B8%8E%E5%AE%9E%E9%99%85%E7%9A%84%E5%9B%BE%E7%89%87%E7%B1%BB%E5%9E%8B%E4%B8%80%E8%87%B4%E3%80%82%E5%A6%82%E6%9E%9C%E4%B8%8D%E4%B8%80%E8%87%B4%EF%BC%8C%E6%B5%8F%E8%A7%88%E5%99%A8%E5%8F%AF%E8%83%BD%E6%97%A0%E6%B3%95%E6%AD%A3%E7%A1%AE%E6%B8%B2%E6%9F%93%E5%9B%BE%E7%89%87%E3%80%82
- %E5%AE%89%E5%85%A8%E6%80%A7%EF%BC%9A%20%E5%A6%82%E6%9E%9CBase64%E5%9B%BE%E7%89%87%E6%95%B0%E6%8D%AE%E6%98%AF%E7%94%A8%E6%88%B7%E4%B8%8A%E4%BC%A0%E7%9A%84%EF%BC%8C%E5%8A%A1%E5%BF%85%E8%BF%9B%E8%A1%8C%E4%B8%A5%E6%A0%BC%E7%9A%84%E9%AA%8C%E8%AF%81%E5%92%8C%E6%B8%85%E7%90%86%EF%BC%8C%E4%BB%A5%E9%98%B2%E6%AD%A2%E6%BD%9C%E5%9C%A8%E7%9A%84%E8%B7%A8%E7%AB%99%E8%84%9A%E6%9C%AC%EF%BC%88XSS%EF%BC%89%E6%94%BB%E5%87%BB%E3%80%82%E8%99%BD%E7%84%B6Base64%E7%BC%96%E7%A0%81%E6%9C%AC%E8%BA%AB%E4%B8%8D%E4%BC%9A%E6%89%A7%E8%A1%8C%E4%BB%A3%E7%A0%81%EF%BC%8C%E4%BD%86%E6%81%B6%E6%84%8F%E7%94%A8%E6%88%B7%E5%8F%AF%E8%83%BD%E4%BC%9A%E4%B8%8A%E4%BC%A0%E5%8C%85%E5%90%AB%E6%81%B6%E6%84%8F%E8%84%9A%E6%9C%AC%E7%9A%84%E5%9B%BE%E7%89%87%EF%BC%8C%E5%A6%82%E6%9E%9C%E8%BF%99%E4%BA%9B%E8%84%9A%E6%9C%AC%E5%9C%A8%E7%89%B9%E5%AE%9A%E4%B8%8A%E4%B8%8B%E6%96%87%E4%B8%AD%E8%A2%AB%E8%A7%A3%E6%9E%90%EF%BC%8C%E5%8F%AF%E8%83%BD%E4%BC%9A%E9%80%A0%E6%88%90%E5%AE%89%E5%85%A8%E9%97%AE%E9%A2%98%E3%80%82
- %E9%A1%B5%E9%9D%A2%E5%88%B7%E6%96%B0%EF%BC%9A%20%E7%A4%BA%E4%BE%8B%E4%BB%A3%E7%A0%81%E4%B8%AD%E4%BD%BF%E7%94%A8%E4%BA%86来实现每2秒自动刷新页面。这对于实时监控摄像头画面等场景很有用,但在其他不需要实时更新的场景中应避免使用,因为它会增加服务器负载和用户数据流量。
6. 总结
正确地在PHP和HTML中显示数据库存储的Base64图片,关键在于理解data: URI的格式,并确保从数据库中提取的数据是完整且未被额外修改的Base64数据URI。避免不必要的编码和字符串操作,直接将数据库中存储的完整Base64字符串输出到











