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Личные заметки на Zaharov.info / Естествознание / GWT Java - Javascript Base64 encoder decoder algorithm |
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dimedrol
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# Дата: 25 Мар 2008 15:28 - Поправил: dimedrol
Ответить Working with GWT we often need to encode data on one side (server side) and to decode on other (client) side. So, finally I have found a working code! See: http://www.source-code.biz/snippets/java/2.htm On the server side (where I can use pure Java) I encode data with this class: package cisgwt.client.createissuebl; /** * A Base64 Encoder/Decoder. * * <p> * This class is used to encode and decode data in Base64 format as described in RFC 1521. * * <p> * This is "Open Source" software and released under the <a href="http://www.gnu.org/licenses/lgpl.html">GNU/LGPL</a> license.<br> * It is provided "as is" without warranty of any kind.<br> * Copyright 2003: Christian d'Heureuse, Inventec Informatik AG, Switzerland.<br> * Home page: <a href="http://www.source-code.biz">www.source-code.biz</a><br> * * <p> * Version history:<br> * 2003-07-22 Christian d'Heureuse (chdh): Module created.<br> * 2005-08-11 chdh: Lincense changed from GPL to LGPL.<br> * 2006-11-21 chdh:<br> * Method encode(String) renamed to encodeString(String).<br> * Method decode(String) renamed to decodeString(String).<br> * New method encode(byte[],int) added.<br> * New method decode(String) added.<br> */ public class Base64Coder { // Mapping table from 6-bit nibbles to Base64 characters. private static char[] map1 = new char[64]; static { int i=0; for (char c='A'; c<='Z'; c++) map1[i++] = c; for (char c='a'; c<='z'; c++) map1[i++] = c; for (char c='0'; c<='9'; c++) map1[i++] = c; map1[i++] = '+'; map1[i++] = '/'; } // Mapping table from Base64 characters to 6-bit nibbles. private static byte[] map2 = new byte[128]; static { for (int i=0; i<map2.length; i++) map2[i] = -1; for (int i=0; i<64; i++) map2[map1[i]] = (byte)i; } /** * Encodes a string into Base64 format. * No blanks or line breaks are inserted. * @param s a String to be encoded. * @return A String with the Base64 encoded data. */ public static String encodeString (String s) { return new String(encode(s.getBytes())); } /** * Encodes a byte array into Base64 format. * No blanks or line breaks are inserted. * @param in an array containing the data bytes to be encoded. * @return A character array with the Base64 encoded data. */ public static char[] encode (byte[] in) { return encode(in,in.length); } /** * Encodes a byte array into Base64 format. * No blanks or line breaks are inserted. * @param in an array containing the data bytes to be encoded. * @param iLen number of bytes to process in <code>in</code>. * @return A character array with the Base64 encoded data. */ public static char[] encode (byte[] in, int iLen) { int oDataLen = (iLen*4+2)/3; // output length without padding int oLen = ((iLen+2)/3)*4; // output length including padding char[] out = new char[oLen]; int ip = 0; int op = 0; while (ip < iLen) { int i0 = in[ip++] & 0xff; int i1 = ip < iLen ? in[ip++] & 0xff : 0; int i2 = ip < iLen ? in[ip++] & 0xff : 0; int o0 = i0 >>> 2; int o1 = ((i0 & 3) << 4) | (i1 >>> 4); int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6); int o3 = i2 & 0x3F; out[op++] = map1[o0]; out[op++] = map1[o1]; out[op] = op < oDataLen ? map1[o2] : '='; op++; out[op] = op < oDataLen ? map1[o3] : '='; op++; } return out; } /** * Decodes a string from Base64 format. * @param s a Base64 String to be decoded. * @return A String containing the decoded data. * @throws IllegalArgumentException if the input is not valid Base64 encoded data. */ public static String decodeString (String s) { return new String(decode(s)); } /** * Decodes a byte array from Base64 format. * @param s a Base64 String to be decoded. * @return An array containing the decoded data bytes. * @throws IllegalArgumentException if the input is not valid Base64 encoded data. */ public static byte[] decode (String s) { return decode(s.toCharArray()); } /** * Decodes a byte array from Base64 format. * No blanks or line breaks are allowed within the Base64 encoded data. * @param in a character array containing the Base64 encoded data. * @return An array containing the decoded data bytes. * @throws IllegalArgumentException if the input is not valid Base64 encoded data. */ public static byte[] decode (char[] in) { int iLen = in.length; if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4."); while (iLen > 0 && in[iLen-1] == '=') iLen--; int oLen = (iLen*3) / 4; byte[] out = new byte[oLen]; int ip = 0; int op = 0; while (ip < iLen) { int i0 = in[ip++]; int i1 = in[ip++]; int i2 = ip < iLen ? in[ip++] : 'A'; int i3 = ip < iLen ? in[ip++] : 'A'; if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127) throw new IllegalArgumentException ("Illegal character in Base64 encoded data."); int b0 = map2[i0]; int b1 = map2[i1]; int b2 = map2[i2]; int b3 = map2[i3]; if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0) throw new IllegalArgumentException ("Illegal character in Base64 encoded data."); int o0 = ( b0 <<2) | (b1>>>4); int o1 = ((b1 & 0xf)<<4) | (b2>>>2); int o2 = ((b2 & 3)<<6) | b3; out[op++] = (byte)o0; if (op<oLen) out[op++] = (byte)o1; if (op<oLen) out[op++] = (byte)o2; } return out; } // Dummy constructor. private Base64Coder() {} } // end class Base64Coder I use the following command: allData = Base64Coder.encodeString(allData); After passing all data to client's browser, in GWT I decode this incoming information with native Javascript function, found here: http://ecmanaut.blogspot.com/2007/11/javascript-base64-singleton.html Source code: // Based on public domain code by Tyler Akins <http://rumkin.com/> // Original code at http://rumkin.com/tools/compression/base64.php var Base64 = (function() { function encode_base64(data) { var out = "", c1, c2, c3, e1, e2, e3, e4; for (var i = 0; i < data.length; ) { c1 = data.charCodeAt(i++); c2 = data.charCodeAt(i++); c3 = data.charCodeAt(i++); e1 = c1 >> 2; e2 = ((c1 & 3) << 4) + (c2 >> 4); e3 = ((c2 & 15) << 2) + (c3 >> 6); e4 = c3 & 63; if (isNaN(c2)) e3 = e4 = 64; else if (isNaN(c3)) e4 = 64; out += tab.charAt(e1) + tab.charAt(e2) + tab.charAt(e3) + tab.charAt(e4); } return out; } function decode_base64(data) { var out = "", c1, c2, c3, e1, e2, e3, e4; for (var i = 0; i < data.length; ) { e1 = tab.indexOf(data.charAt(i++)); e2 = tab.indexOf(data.charAt(i++)); e3 = tab.indexOf(data.charAt(i++)); e4 = tab.indexOf(data.charAt(i++)); c1 = (e1 << 2) + (e2 >> 4); c2 = ((e2 & 15) << 4) + (e3 >> 2); c3 = ((e3 & 3) << 6) + e4; out += String.fromCharCode(c1); if (e3 != 64) out += String.fromCharCode(c2); if (e4 != 64) out += String.fromCharCode(c3); } return out; } var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; return { encode:encode_base64, decode:decode_base64 }; })(); I transformed needed function to this (GWT native javascript function - just copy and paste it): public static native String base64decode(final String data) /*-{ var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; var out = "", c1, c2, c3, e1, e2, e3, e4; for (var i = 0; i < data.length; ) { e1 = tab.indexOf(data.charAt(i++)); e2 = tab.indexOf(data.charAt(i++)); e3 = tab.indexOf(data.charAt(i++)); e4 = tab.indexOf(data.charAt(i++)); c1 = (e1 << 2) + (e2 >> 4); c2 = ((e2 & 15) << 4) + (e3 >> 2); c3 = ((e3 & 3) << 6) + e4; out += String.fromCharCode(c1); if (e3 != 64) out += String.fromCharCode(c2); if (e4 != 64) out += String.fromCharCode(c3); } return out; }-*/; This is working fine! final String decodedServerData = base64decode(dataFromServer); eof |