java8解码以base64编码的图像

Question

我正在尝试使用java.util.Base64（java8）解码用base64字符串编码的图像。

这是base64编码的字符串：

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 29/j5+v/aAAwDAQACEQMRAD8AvazJDPdraSXEcIijMoLuF+c8J19OT+VaWn3QvLGG4GPnXkDse4/OoNJ+cXUzcvJcOCfZTtA/IVny3ktje3cMG0J5u/BGcEqpP6mgD//Z

可以在http://codebeautify.org/base64-to-image-converter

上解码

当我尝试将base64字符串解码为byte时。我收到此错误消息：

java.lang.IllegalArgumentException: Illegal base64 character 20

这是我的代码：

String base64Str = "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 29/j5+v/aAAwDAQACEQMRAD8AvazJDPdraSXEcIijMoLuF+c8J19OT+VaWn3QvLGG4GPnXkDse4/OoNJ+cXUzcvJcOCfZTtA/IVny3ktje3cMG0J5u/BGcEqpP6mgD//Z";
byte[] imageByteArray_new = Base64.getDecoder().decode(base64Str);

我不知道出了什么问题。请帮助，谢谢

Answer 1

您的编码字符串中有一个空格，这是base64中的非法字符。如果删除它，它仍会在链接到的转换器中生成相同的图像，现在也可以通过代码进行解码。

<强>更新

某些解码器（如您链接的解码器或Java中的Base64.getMimeDecoder()）会忽略非法字符，而其他解码器（如Base64.getDecoder()）则不允许使用它们。

Answer 2

当我通过@RequestParam接收到base64字符串时，遇到了相同的问题，它将“ +”接收为“”。

Base64.getDecoder().decode()给了我同样的异常（java.lang.IllegalArgumentException：非法的base64字符20） 和Base64.getMimeDecoder()只是忽略了空格，并以错误保存了图像。

修复：

public byte[] convertImage(String base64) { String base64Image = base64.replaceAll(" ", "+"); return byte[] imageBytes = java.util.Base64.getDecoder().decode(base64Image); }

对我有用。

Answer 3

是的，它也对我有用。非常感谢。

 String base64Image = base64.replaceAll(" ", "+");

查询-我会说这是临时解决方案，因为在加密的字符串中，如果为空或任何其他字符，将无法使用。