I have a base64 string like this = "pCZXOVjpnlePyDk6znZrSw==" i need a encoder/decoder to convert it to decimal string like this = "84587163248712923874"
Is there any codec that do it?
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Jeff Mercado
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Sajad Bahmani
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Language, platform, context? It's also unclear what digits those are meant to be... please give more information. – Jon Skeet Sep 23 '11 at 11:31
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encode/decode base64 to a string that contain only digits. java – Sajad Bahmani Sep 23 '11 at 11:34
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That base 64 string decodes to the 16 bytes A426573958E99E578FC8393ACE766B4B whats their relationship to the number? – Alex K. Sep 23 '11 at 11:39
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base64 is base64. However, the encoder works only on bytes, so you must convert your characters to bytes before encoding, and convert back after decoding. – Hot Licks Sep 23 '11 at 11:44
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http://stackoverflow.com/questions/469695/decode-base64-data-in-java tells you how to decode a base64 string, as for what you get back; if its an encoded decimal string that's what you will get, if its a picture of a cat, then you'll get that. – Alex K. Sep 23 '11 at 11:45
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You probably need a two stage process:
- Convert the Base64 string to a byte array.
- Convert the byte array to a number.
16 bytes is too big for a Java long so I assume that you will need a BigInteger. There is a BigInteger constructor that takes a byte array as parameter, though you will need to be careful with the sign bit. The toString() method for the BigInteger will give you the string you want.
rossum
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Base64 encode/decode is part of the default libraries now (finally). Look at the class javax.xml.bind.DatatypeConverter. In there you will find two methods printBase64Binary and parseBase64Binary (along with a few other conversion routines).
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This tells how to parse base64, but not how to convert the result (a byte array) to a decimal string. – LarsH May 17 '18 at 00:24