Base64加解密

来源：互联网发布：java引用传递编辑：程序博客网时间：2024/06/11 15:55

import java.io.UnsupportedEncodingException;public class Base64 {    private static char[] base64EncodeChars = new char[]{            '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', '+', '/'};    private static byte[] base64DecodeChars = new byte[]{            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,            52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,            -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,            15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,            -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,            41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1};       public static String encode(byte[] data) {        StringBuffer sb = new StringBuffer();        int len = data.length;        int i = 0;        int b1, b2, b3;        while (i < len) {            b1 = data[i++] & 0xff;            if (i == len) {                sb.append(base64EncodeChars[b1 >>> 2]);                sb.append(base64EncodeChars[(b1 & 0x3) << 4]);                sb.append("==");                break;            }            b2 = data[i++] & 0xff;            if (i == len) {                sb.append(base64EncodeChars[b1 >>> 2]);                sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);                sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);                sb.append("=");                break;            }            b3 = data[i++] & 0xff;            sb.append(base64EncodeChars[b1 >>> 2]);            sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);            sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);            sb.append(base64EncodeChars[b3 & 0x3f]);        }        return sb.toString();    }       public static byte[] decode(String str) throws UnsupportedEncodingException {        StringBuffer sb = new StringBuffer();        byte[] data = str.getBytes("US-ASCII");        int len = data.length;        int i = 0;        int b1, b2, b3, b4;        while (i < len) {                       do {                b1 = base64DecodeChars[data[i++]];            } while (i < len && b1 == -1);            if (b1 == -1) break;                       do {                b2 = base64DecodeChars                        [data[i++]];            } while (i < len && b2 == -1);            if (b2 == -1) break;            sb.append((char) ((b1 << 2) | ((b2 & 0x30) >>> 4)));                       do {                b3 = data[i++];                if (b3 == 61) return sb.toString().getBytes("iso8859-1");                b3 = base64DecodeChars[b3];            } while (i < len && b3 == -1);            if (b3 == -1) break;            sb.append((char) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));                       do {                b4 = data[i++];                if (b4 == 61) return sb.toString().getBytes("iso8859-1");                b4 = base64DecodeChars[b4];            } while (i < len && b4 == -1);            if (b4 == -1) break;            sb.append((char) (((b3 & 0x03) << 6) | b4));        }        return sb.toString().getBytes("iso8859-1");    }    public static void main(String[] args) throws UnsupportedEncodingException {        String s = "忆君迢迢隔青天，昔日横波目，今作流泪泉，不信妾断肠，归来看取明镜前！";        System.out.println("加密前：" + s);        String x = encode(s.getBytes());        System.out.println("加密后：" + x);        String x1 = new String(decode(x));        System.out.println("解密后：" + x1);    }}

加密前：忆君迢迢隔青天，昔日横波目，今作流泪泉，不信妾断肠，归来看取明镜前！
加密后：5b+G5ZCb6L+i6L+i6ZqU6Z2S5aSp77yM5piU5pel5qiq5rOi55uu77yM5LuK5L2c5rWB5rOq5rOJ77yM5LiN5L+h5aa+5pat6IKg77yM5b2S5p2l55yL5Y+W5piO6ZWc5YmN77yB
解密后：忆君迢迢隔青天，昔日横波目，今作流泪泉，不信妾断肠，归来看取明镜前！

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