Hex String to Image [英] Hex String to Image

问题描述

我有一个十六进制字符串，如下所示：

I have a hex string which looks like:

String hexImage ="0xFFD8FFE000104A46494600010200006400640000FFEC00114475636B79000100040000003C..."

我需要使用Java转换为图像。我已经尝试使用org.apache.commons.codec.binary.Hex类首先转换为字节数组。 FileOutputStream稍后将其转储到文件中。

Which I need to convert to an image using Java. I've tried converting to a byte array first with org.apache.commons.codec.binary.Hex class. FileOutputStream later dumps this to a file.

char[] charArr= hexImage.toCharArray();
byte[] byteArray = Hex.decodeHex(charArr);

然而，Hex类中的解析器会窒息，并带有Decoder异常：奇数个字符。无论我使用什么方法转换为字节数组，它都会失败。 fileformat肯定是JPEG。

however the parser in the Hex class chokes, with an Decoder exception : Odd number of characters. No matter what method I use to convert to a byte array, it fails. The fileformat is definitely a JPEG.

我尝试从字符串中删除 this 0xFF，但此时图像已损坏。 0xFF我认为是罪魁祸首 - 有什么想法我需要做些什么才能纠正这个问题？

I've tried removing this 0xFF from the string, but the image is corrupt at this point. 0xFF I assume is a the culprit - anyone any ideas on what do I need to do to correct this?

推荐答案

通常，每个人byte由2个十六进制数字表示，因此，如果你的HEX字符串中有一个奇数位数，那么它就有问题了。您可以尝试在开头填充0，例如：

Normally, each byte is represented by 2 hex digits, therefore, if you have an odd number of digits in your HEX string, then something is wrong with it. You can try padding it with 0 in the beginning, such as this:

String hexImage ="0xFFD8FFE000104A46494600010200006400640000FFEC00114475636B79000100040000003C...";
if(hexImage.length()%2 == 1)
    hexImage = "0x0" + hexImage.substring(2);

或最后，例如：

String hexImage ="0xFFD8FFE000104A46494600010200006400640000FFEC00114475636B79000100040000003C...";
if(hexImage.length()%2 == 1)
    hexImage += "0";

然而，这不能保证产生合适的图像。

However this is not guaranteed to produce a proper image.

总的来说，你应该检查你是如何获得十六进制字符串的。正确的字节序列应始终包含偶数个十六进制数字。

On the whole, you should check how you get your hex string. A proper byte sequence should always contain an even number of hex digits.

编辑：此外，正如Peter Lawrey在评论中指出的那样，应检查 decode 方法是否在字符串前面需要 0x 。

In addition, as Peter Lawrey indicated in his comment, you should check whether the decode method expects 0x in front of the string.

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