Java XxteaUtils工具类

import java.io.UnsupportedEncodingException;

public class XxteaUtils {
/**
* Encrypt data with key.
*
* @param data
* @param key
* @return
*/
public static byte[] encrypt(byte[] data, byte[] key) {
if (data.length == 0) {
return data;
}
return toByteArray(encrypt(toIntArray(data, true), toIntArray(key, false)), false);
}

/**
* Decrypt data with key.
*
* @param data
* @param key
* @return
*/
public static byte[] decrypt(byte[] data, byte[] key) {
if (data.length == 0) {
return data;
}
return toByteArray(decrypt(toIntArray(data, false), toIntArray(key, false)), true);
}

/**
* Encrypt data with key.
*
* @param v
* @param k
* @return
*/
public static int[] encrypt(int[] v, int[] k) {
int n = v.length - 1;
if (n < 1) {
return v;
}
if (k.length < 4) {
int[] key = new int[4];
System.arraycopy(k, 0, key, 0, k.length);
k = key;
}
int z = v
, y = v[0], delta = 0x9E3779B9, sum = 0, e;
int p, q = 6 + 52 / (n + 1);
while (q-- > 0) {
sum = sum + delta;
e = sum >>> 2 & 3;
for (p = 0; p < n; p++) {
y = v[p + 1];
z = v[p] += (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
}
y = v[0];
z = v
+= (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
}
return v;
}

/**
* Decrypt data with key.
*
* @param v
* @param k
* @return
*/
public static int[] decrypt(int[] v, int[] k) {
int n = v.length - 1;
if (n < 1) {
return v;
}
if (k.length < 4) {
int[] key = new int[4];
System.arraycopy(k, 0, key, 0, k.length);
k = key;
}
int z = v
, y = v[0], delta = 0x9E3779B9, sum, e;
int p, q = 6 + 52 / (n + 1);
sum = q * delta;
while (sum != 0) {
e = sum >>> 2 & 3;
for (p = n; p > 0; p--) {
z = v[p - 1];
y = v[p] -= (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
}
z = v
;
y = v[0] -= (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
sum = sum - delta;
}
return v;
}

/**
* Convert byte array to int array.
*
* @param data
* @param includeLength
* @return
*/
private static int[] toIntArray(byte[] data, boolean includeLength) {
int n = (((data.length & 3) == 0) ? (data.length >>> 2) : ((data.length >>> 2) + 1));
int[] result;
if (includeLength) {
result = new int[n + 1];
result
= data.length;
} else {
result = new int
;
}
n = data.length;
for (int i = 0; i < n; i++) {
result[i >>> 2] |= (0x000000ff & data[i]) << ((i & 3) << 3);
}
return result;
}

/**
* Convert int array to byte array.
*
* @param data
* @param includeLength
* @return
*/
private static byte[] toByteArray(int[] data, boolean includeLength) {
int n;
if (includeLength) {
n = data[data.length - 1];
} else {
n = data.length << 2;
}

byte[] result = new byte
;
for (int i = 0; i < n; i++) {
result[i] = (byte) (data[i >>> 2] >>> ((i & 3) << 3));
}
return result;
}

/**
* 字节数组转换为hex字符串
*
* @param bArray
* @return
*/
private static final String bytesToHexString(byte[] bArray) {
StringBuffer sb = new StringBuffer(bArray.length);

for (int i = 0; i < bArray.length; ++i) {
String sTemp = Integer.toHexString(0xFF & bArray[i]);
if (sTemp.length() < 2)
sb.append(0);
sb.append(sTemp.toUpperCase());
}
return sb.toString();
}

/**
* hex字符串转换为字节数组
*
* @param str
* @return
*/
private static byte[] hexToBytes(String str) {
if (str == null) {
return null;
}

char[] hex = str.toCharArray();

int length = hex.length / 2;
byte[] raw = new byte[length];
for (int i = 0; i < length; ++i) {
int high = Character.digit(hex[(i * 2)], 16);
int low = Character.digit(hex[(i * 2 + 1)], 16);
int value = high << 4 | low;
if (value > 127)
value -= 256;
raw[i] = (byte) value;
}
return raw;
}

/**
* 使用XXTea 算法加密字符串
*
* @param plain
*            被加密的字符串
* @param charset
*            字符集
* @param key
*            密钥
* @return 加密之后的hex 字符串
* @throws UnsupportedEncodingException
*/
public static String encryptStr(String plain, String charset, String key) throws Exception {
if (plain == null || charset == null || key == null) {
return null;
}
byte[] bytes = encrypt(plain.getBytes(charset), key.getBytes(charset));

return bytesToHexString(bytes);
}

/**
* 使用XXTea 算法解密字符串
*
* @param hexStr
*            加密之后的hex 字符串
* @param charset
*            字符集
* @param key
*            密钥
* @return 解密之后的字符串
* @throws UnsupportedEncodingException
*/
public static String decryptStr(String hexStr, String charset, String key) throws Exception {
if (hexStr == null || charset == null || key == null) {
return null;
}
byte[] bytes = decrypt(hexToBytes(hexStr), key.getBytes(charset));

return new String(bytes, charset);
}
}