base64的java实现方法

package cn.eshore.mismp.sms.ws.send;public class Base64 {/** * 将原始数据编码为base64编码 */static public char[] encode(byte[] data) {char[] out = new char[((data.length + 2) / 3) * 4];for (int i = 0, index = 0; i < data.length; i += 3, index += 4) {boolean quad = false;boolean trip = false;int val = (0xFF & (int) data[i]);val <<= 8;if ((i + 1) < data.length) {val |= (0xFF & (int) data[i + 1]);trip = true;}val <<= 8;if ((i + 2) < data.length) {val |= (0xFF & (int) data[i + 2]);quad = true;}out[index + 3] = alphabet[(quad ? (val & 0x3F) : 64)];val >>= 6;out[index + 2] = alphabet[(trip ? (val & 0x3F) : 64)];val >>= 6;out[index + 1] = alphabet[val & 0x3F];val >>= 6;out[index + 0] = alphabet[val & 0x3F];}return out;}/** * 将base64编码的数据解码成原始数据 */static public byte[] decode(char[] data) {int len = ((data.length + 3) / 4) * 3;if (data.length > 0 && data[data.length - 1] == '=')--len;if (data.length > 1 && data[data.length - 2] == '=')--len;byte[] out = new byte[len];int shift = 0;int accum = 0;int index = 0;for (int ix = 0; ix < data.length; ix++) {int value = codes[data[ix] & 0xFF];if (value >= 0) {accum <<= 6;shift += 6;accum |= value;if (shift >= 8) {shift -= 8;out[index++] = (byte) ((accum >> shift) & 0xff);}}}if (index != out.length)throw new Error("miscalculated data length!");return out;}static private char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=".toCharArray();static private byte[] codes = new byte[256];static {for (int i = 0; i < 256; i++)codes[i] = -1;for (int i = 'A'; i <= 'Z'; i++)codes[i] = (byte) (i - 'A');for (int i = 'a'; i <= 'z'; i++)codes[i] = (byte) (26 + i - 'a');for (int i = '0'; i <= '9'; i++)codes[i] = (byte) (52 + i - '0');codes['+'] = 62;codes['/'] = 63;}public static void main(String[] args) throws Exception {// 加密成base64String strSrc = "林";String strOut = new String(Base64.encode(strSrc.getBytes("GB18030")));System.out.println(strOut);String strOut2 = new String(Base64.decode(strOut.toCharArray()),"GB18030");System.out.println(strOut2);}}