Copy-pasted from: http://www.wikihow.com/Encode-a-String-to-Base64-With-Java
public class Base64 { private static final String base64code = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz" + "0123456789" + "+/"; private static final int splitLinesAt = 76; public static byte[] zeroPad(int length, byte[] bytes) { byte[] padded = new byte[length]; // initialized to zero by JVM System.arraycopy(bytes, 0, padded, 0, bytes.length); return padded; } public static String encode(String string) { String encoded = ""; byte[] stringArray; try { stringArray = string.getBytes("UTF-8"); // use appropriate encoding string! } catch (Exception ignored) { stringArray = string.getBytes(); // use locale default rather than croak } // determine how many padding bytes to add to the output int paddingCount = (3 - (stringArray.length % 3)) % 3; // add any necessary padding to the input stringArray = zeroPad(stringArray.length + paddingCount, stringArray); // process 3 bytes at a time, churning out 4 output bytes // worry about CRLF insertions later for (int i = 0; i < stringArray.length; i += 3) { int j = ((stringArray[i] & 0xff) << 16) + ((stringArray[i + 1] & 0xff) << 8) + (stringArray[i + 2] & 0xff); encoded = encoded + base64code.charAt((j >> 18) & 0x3f) + base64code.charAt((j >> 12) & 0x3f) + base64code.charAt((j >> 6) & 0x3f) + base64code.charAt(j & 0x3f); } // replace encoded padding nulls with "=" return splitLines(encoded.substring(0, encoded.length() - paddingCount) + "==".substring(0, paddingCount)); } public static String splitLines(String string) { String lines = ""; for (int i = 0; i < string.length(); i += splitLinesAt) { lines += string.substring(i, Math.min(string.length(), i + splitLinesAt)); lines += "\r\n"; } return lines; } public static void main(String[] args) { for (int i = 0; i < args.length; i++) { System.err.println("encoding \"" + args[i] + "\""); System.out.println(encode(args[i])); } } }
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