将Data-URL转换为BufferedImage [英] Convert Data-URL to BufferedImage

问题描述

我有一个来自图像文件的数据URL，必须将其传递给另一个函数。沿着从Data-URL到BufferedImage的这条路径，它需要是一个byteArray。

I have a Data-URL from an image file and have to pass it through to another function. Along this path from Data-URL to the BufferedImage it needs to be a byteArray.

我的方法如下：

String dataUrl;
byte[] imageData = dataUrl.getBytes();

// pass the byteArray along the path

// create BufferedImage from byteArray
BufferedImage inputImage = ImageIO.read(new ByteArrayInputStream(imageData));

// If the picture is null, then throw an unsupported image exception.
if (inputImage == null) {
    throw new UnknownImageFormatException();
}

问题是，它总是抛出UnknownImageFormatException异常，这意味着inputImage为null ，这意味着，ImageIO.read无法识别图像类型。

The problem is, it always throws the UnknownImageFormatException Exception, which means inputImage is null, which means, the ImageIO.read did not recognize the imagetype.

我使用ImageIO.getReaderFormatNames（）来获取支持的文件名，并得到以下列表： / p>

I've used ImageIO.getReaderFormatNames() to get the supported Filenames and got the following list:

Supported Formats: 
jpg, BMP, bmp, JPG, jpeg, wbmp, png, JPEG, PNG, WBMP, GIF, gif

我尝试传递的dataURL如下： data：image / png; base64，... 或数据：image / jpg; base64，...

The dataURLs I try to pass are like: data:image/png;base64,... or data:image/jpg;base64,...

据我所知，这些都在支持的文件列表中，因此应该被识别。

As far as I understand, those are in the supported filelist and therefor should be recognized.

在这种情况下还有什么可能导致inputImage为null ？更有趣的是，我该如何解决呢？

What else could cause the inputImage to be null in this case? And more interesting, how do I solve it?

推荐答案

由于评论已经说明图像数据是Base64编码的。要检索二进制数据，您必须删除类型/编码标头，然后将Base64内容解码为二进制数据。

As the comments already said the image data is Base64 encoded. To retrieve the binary data you have to strip the type/encoding headers, then decode the Base64 content to binary data.

String encodingPrefix = "base64,";
int contentStartIndex = dataUrl.indexOf(encodingPrefix) + encodingPrefix.length();
byte[] imageData = Base64.decodeBase64(dataUrl.substring(contentStartIndex));

我使用 org.apache.commons.codec.binary.Base64 ，其他Base64解码器也可以正常工作。

I use org.apache.commons.codec.binary.Base64 from apaches common-codec, other Base64 decoders should work as well.

这篇关于将Data-URL转换为BufferedImage的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！