Android 对字符串进行MD5 和base64 加密

对字符串进行MD5加密
/**
* MD5加密
* @param str 内容
* @param charset 编码方式
* @throws Exception
*/
@SuppressWarnings("unused")
public static String MD5(String str, String charset) throws Exception {
MessageDigest md = MessageDigest.getInstance("MD5");
md.update(str.getBytes(charset));
byte[] result = md.digest();
StringBuffer sb = new StringBuffer(32);
for (int i = 0; i < result.length; i++) {
int val = result[i] & 0xff;
if (val <= 0xf) {
sb.append("0");
}
sb.append(Integer.toHexString(val));
}
return sb.toString().toLowerCase();
}对字符串进行base64加密
/**
* base64编码
* @param str 内容
* @param charset 编码方式
* @throws UnsupportedEncodingException
*/
public static String base64(String str, String charset) throws UnsupportedEncodingException {
String encoded = base64Encode(str.getBytes(charset));
return encoded;
}

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', '+', '/' };

public static String base64Encode(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();
}