如何将base64位的字节数组转换成图片并显示

Posted 2023-05-15

不用保存成文件。

写一个servlet(假设名字是servletImg)，页面的参数就是 id，然后将从DB得到的图像的byte[]，通过流输出给页面。

页面还是 <img src="servletImg?id=1234" />

这样的逻辑，才行。 参考技术A 在C#中
图片到byte[]再到base64string的转换：
Bitmap bmp = new Bitmap(filepath);
MemoryStream ms = new MemoryStream();
bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
byte[] arr = new byte[ms.Length];
ms.Position = 0;
ms.Read(arr, 0, (int)ms.Length);
ms.Close();
string pic = Convert.ToBase64String(arr);
base64string到byte[]再到图片的转换：
byte[] imageBytes = Convert.FromBase64String(pic);
//读入MemoryStream对象
MemoryStream memoryStream = new MemoryStream(imageBytes, 0, imageBytes.Length);
memoryStream.Write(imageBytes, 0, imageBytes.Length);
//转成图片
Image image = Image.FromStream(memoryStream);

如何将图像的字节数组转换为表示 jpg 的 base64 编码字符串

【中文标题】如何将图像的字节数组转换为表示 jpg 的 base64 编码字符串

【英文标题】：How to convert byte array of an image to a base64 encoded string representing a jpg

【发布时间】：2015-08-21 02:16:36

【问题描述】：

我正在编写一个拍摄照片并上传照片的 Android 应用。

API 需要一个表示要上传的 jpg 的 base 64 编码字符串。

Camera API 给了我一个byte []。

如何将此字节数组转换为 base64 编码字符串，以确保保持 jpg 格式？

目前，我正在尝试String encoded = Base64.encodeToString(byteArray, Base64.NO_WRAP);

但这不知何故是无效的，在日志中给了我一堆AAAAAAAAAs，而不是真正的base64编码字符串。

感谢您的帮助

编辑：

其实，当我退出上面encoded的内容时，我得到了

 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

但是当它实际发布到服务器时（使用 Square 的 Retrofit 库），我会收到数十万个 AAAAAs，这会破坏服务器。

尽管如此，但记录的编码字符串似乎不够长，无法封装与 LG G3 中的照片相关的所有数据。

【问题讨论】：

Base64.encodeBase64(byteArray).toString()?

您尝试以哪种格式保存在服务器上????????

【参考方案1】：

使用

byte [] data = Base64.decode(base64str);

您需要在项目中引用 commons codec 才能使该代码正常工作。