package com.ssish.wxmall.common.data; import java.io.ByteArrayOutputStream; import java.util.Random; /** * base64 * @author zhangkun 2019-01-02 21:52:00 * */ public class Base64 { private static final char[] chars64 = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' }; // map char to 6-bit int private static final int[] ints64 = new int[128]; static { for (int i = 0; i < 64; i++) { ints64[chars64[i]] = i; } } public static String encodeStr(String newStr) { if (newStr == null || newStr.length() == 0) return null; String encoded = encode(newStr.getBytes()); if (encoded == null || encoded.length() == 0) return null; return java.net.URLEncoder.encode(encoded); } /** Convert byte array into Base64 string */ public static final String encode(byte[] unencoded) { // Take 24-bits from three octets, translate into four encoded chars. // If necessary, pad with 0 bits on the right at the end // Use = signs as padding at the end to ensure encodedLength % 4 == 0 if (unencoded == null || unencoded.length == 0) return null; ByteArrayOutputStream out = new ByteArrayOutputStream((int) (unencoded.length * 1.37)); int byteCount = 0; int carryOver = 0; for (int i = 0; i < unencoded.length; i++) { int bc = (byteCount % 3); byte b = unencoded[i]; int lookup = 0; // First byte use first six bits, save last two bits if (bc == 0) { lookup = (b >> 2) & 0x3F; carryOver = b & 0x03; // last two bits out.write(chars64[lookup]); } else if (bc == 1) { // Second byte use previous two bits and first four new bits, // save last four bits lookup = ((carryOver << 4) | ((b >> 4) & 0x0F)); carryOver = b & 0x0F; // last four bits out.write(chars64[lookup]); } else if (bc == 2) { // Third byte use previous four bits and first two new bits, // then use last six new bits lookup = ((carryOver << 2) | ((b >> 6) & 0x03)); out.write(chars64[lookup]); lookup = b & 0x3F; // last six bits out.write(chars64[lookup]); carryOver = 0; } byteCount++; } if (byteCount % 3 == 1) { // one leftover int lookup = (carryOver << 4) & 0xF0; out.write(chars64[lookup]); out.write('='); out.write('='); } else if (byteCount % 3 == 2) { // two leftovers int lookup = (carryOver << 2) & 0x3C; out.write(chars64[lookup]); out.write('='); } return out.toString(); } /** Decode Base64 string back to byte array */ public static final byte[] decode(String encoded) { if (encoded == null || encoded.length() == 0) return null; byte[] bytes = encoded.getBytes(); ByteArrayOutputStream out = new ByteArrayOutputStream((int) (bytes.length * 0.67)); int byteCount = 0; int carryOver = 0; DECODE_LOOP : for (int i = 0; i < bytes.length; i++) { int ch = bytes[i]; // Read the next non-whitespace character //if (Character.isWhitespace((char)ch)) // continue; // The '=' sign is just padding; geffective end of stream if (ch == '=') break DECODE_LOOP; // Convert from raw form to 6-bit form int newbits = ints64[ch]; int bc = (byteCount % 4); if (bc == 0) { // First char save all six bits, go for another carryOver = newbits & 0x3F; } else if (bc == 1) { // second char use 6 previous bits and first 2 new bits int data = ((carryOver << 2) + ((newbits >> 4) & 0x03)); out.write(data); carryOver = newbits & 0x0F; // save 4 bits } else if (bc == 2) { // Third char use previous four bits and first four new bits, // save last two bits int data = ((carryOver << 4) + ((newbits >> 2) & 0x0F)); out.write(data); carryOver = newbits & 0x03; // save 2 bits } else if (bc == 3) { // Fourth char use previous two bits and all six new bits int data = ((carryOver << 6) + (newbits & 0x3F)); out.write(data); carryOver = 0; } byteCount++; } return out.toByteArray(); } /** * UNIT TEST */ public static String str = "This is a test"; public static void main(String[] args) throws Exception { //test1(args); test1(new String[]{"dfdfd"}); } private static void test1(String[] args) { if (args.length > 0) { str = args[0]; } printString("Start", str); String encoded = Base64.encode(str.getBytes()); printString("Encoded", encoded); String decoded = new String(Base64.decode(encoded)); printString("Decoded", decoded); System.err.println("** " + (decoded.equals(str) ? "SUCCESS" : "FAILURE")); } public static void test2(String[] args) throws Exception { int count = 30; if (args.length > 0) { count = Integer.parseInt(args[0]); } if (count <= 0) count = 30; byte[] data = new byte[count]; Random rand = new Random(); rand.nextBytes(data); printBytes("Source", data); String encoded = Base64.encode(data); printString("Encoded", encoded); byte[] bin = Base64.decode(encoded); printBytes("Final", bin); if (bin.length != data.length) { System.err.println("::FAILURE::"); return; } for (int i = 0; i < bin.length; i++) { if (bin[i] != data[i]) { System.err.println("::FAILURE::"); return; } } System.err.println("::SUCCESS::"); } private static void printString(String prompt, String s) { System.err.println("** " + prompt + "='" + s + "' (length=" + s.length() + ")"); } public static void printBytes(String prompt, byte[] data) { System.err.print("** " + prompt + " = ["); for (int i = 0; i < data.length; i++) { String sep = ","; if (i == 0) sep = ""; System.err.print(sep + data[i]); } System.err.println("] (length=" + data.length + ")"); } }
base64加密工具类
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转载自blog.csdn.net/qq_31594647/article/details/86645773
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