背景
最近在項目中需要使用到AES、RSA、MD5、SHA的加解密，整理了工具類，放出來記錄一下，完整的源碼已經放到github上。
加解密
AES
/**
* AES 工具類
*/
public class AESUtil {
private final static String SHA1PRNG = "SHA1PRNG";
@IntDef({Cipher.ENCRYPT_MODE, Cipher.DECRYPT_MODE})
@interface AESType {}
/**
* Aes加密/解密
*
* @param content 字符串
* @param password 密鑰
* @param type 加密：{@link Cipher#ENCRYPT_MODE}，解密：{@link Cipher#DECRYPT_MODE}
* @return 加密/解密結果字符串
*/
public static String aes(String content, String password, @AESType int type) {
try {
KeyGenerator generator = KeyGenerator.getInstance("AES");
SecureRandom secureRandom;
if (android.os.Build.VERSION.SDK_INT >= 24) {
secureRandom = SecureRandom.getInstance(SHA1PRNG, new CryptoProvider());
} else if (android.os.Build.VERSION.SDK_INT >= 17) {
secureRandom = SecureRandom.getInstance(SHA1PRNG, "Crypto");
} else {
secureRandom = SecureRandom.getInstance(SHA1PRNG);
}
secureRandom.setSeed(password.getBytes());
generator.init(128, secureRandom);
SecretKey secretKey = generator.generateKey();
byte[] enCodeFormat = secretKey.getEncoded();
SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
@SuppressLint("GetInstance") Cipher cipher = Cipher.getInstance("AES");
cipher.init(type, key);
if (type == Cipher.ENCRYPT_MODE) {
byte[] byteContent = content.getBytes("utf-8");
return parseByte2HexStr(cipher.doFinal(byteContent));
} else {
byte[] byteContent = parseHexStr2Byte(content);
return new String(cipher.doFinal(byteContent));
}
} catch (NoSuchAlgorithmException | BadPaddingException | IllegalBlockSizeException |
UnsupportedEncodingException | InvalidKeyException | NoSuchPaddingException |
NoSuchProviderException e) {
e.printStackTrace();
}
return null;
}
}
RSA
/**
* RSA 工具類
*/
public class RSAUtil {
/**
* 隨機獲取密鑰(公鑰和私鑰), 客戶端公鑰加密，服務器私鑰解密
*
* @return 結果密鑰對
* @throws Exception 異常
*/
public static Map<String, Object> getKeyPair() throws Exception {
KeyPairGenerator keyPairGen = getKeyPairGenerator();
keyPairGen.initialize(1024);
KeyPair keyPair = keyPairGen.generateKeyPair();
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
Map<String, Object> keyMap = new HashMap<>(2);
keyMap.put("RSAPublicKey", publicKey);
keyMap.put("RSAPrivateKey", privateKey);
return keyMap;
}
/**
* 獲取公鑰/私鑰
*
* @param keyMap 密鑰對
* @param isPublicKey true：獲取公鑰，false：獲取私鑰
* @return 獲取密鑰字符串
*/
public static String getKey(Map<String, Object> keyMap, boolean isPublicKey) {
Key key = (Key) keyMap.get(isPublicKey ? "RSAPublicKey" : "RSAPrivateKey");
return new String(Base64.encode(key.getEncoded(), Base64.DEFAULT));
}
/**
* 獲取數字簽名
*
* @param data 二進制位
* @param privateKey 私鑰(BASE64編碼)
* @return 數字簽名結果字符串
* @throws Exception 異常
*/
public static String sign(byte[] data, String privateKey) throws Exception {
byte[] keyBytes = Base64.decode(privateKey.getBytes(), Base64.DEFAULT);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = getKeyFactory();
PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Signature signature = Signature.getInstance("MD5withRSA");
signature.initSign(privateK);
signature.update(data);
return new String(Base64.encode(signature.sign(), Base64.DEFAULT));
}
/**
* 數字簽名校驗
*
* @param data 二進位組
* @param publicKey 公鑰(BASE64編碼)
* @param sign 數字簽名字符串
* @return true：校驗成功，false：校驗失敗
* @throws Exception 異常
*/
public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
byte[] keyBytes = Base64.decode(publicKey.getBytes(), Base64.DEFAULT);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = getKeyFactory();
PublicKey publicK = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance("MD5withRSA");
signature.initVerify(publicK);
signature.update(data);
return signature.verify(Base64.decode(sign.getBytes(), Base64.DEFAULT));
}
/**
* 獲取 KeyFactory
*
* @throws NoSuchAlgorithmException 異常
*/
private static KeyFactory getKeyFactory() throws NoSuchAlgorithmException,
NoSuchProviderException {
KeyFactory keyFactory;
if (Build.VERSION.SDK_INT >= 16) {
keyFactory = KeyFactory.getInstance("RSA", "BC");
} else {
keyFactory = KeyFactory.getInstance("RSA");
}
return keyFactory;
}
/**
* 獲取 KeyFactory
*
* @throws NoSuchAlgorithmException 異常
*/
private static KeyPairGenerator getKeyPairGenerator() throws NoSuchProviderException,
NoSuchAlgorithmException {
KeyPairGenerator keyPairGen;
if (Build.VERSION.SDK_INT >= 16) {
keyPairGen = KeyPairGenerator.getInstance("RSA", "BC");
} else {
keyPairGen = KeyPairGenerator.getInstance("RSA");
}
return keyPairGen;
}
/**
* Rsa公鑰加密類型
*/
public static final int RSA_PUBLIC_ENCRYPT = 0;
/**
* Rsa公鑰解密類型
*/
public static final int RSA_PUBLIC_DECRYPT = 1;
/**
* Rsa私鑰加密類型
*/
public static final int RSA_PRIVATE_ENCRYPT = 2;
/**
* Rsa私鑰解密類型
*/
public static final int RSA_PRIVATE_DECRYPT = 3;
@IntDef({RSA_PUBLIC_ENCRYPT, RSA_PUBLIC_DECRYPT, RSA_PRIVATE_ENCRYPT, RSA_PRIVATE_DECRYPT})
@interface RSAType {}
/**
* Rsa加密/解密（一般情況下，公鑰加密私鑰解密）
*
* @param data 源數據
* @param string 密鑰(BASE64編碼)
* @param type 操作類型：{@link #RSA_PUBLIC_ENCRYPT}，{@link #RSA_PUBLIC_DECRYPT
* }，{@link #RSA_PRIVATE_ENCRYPT}，{@link #RSA_PRIVATE_DECRYPT}
* @return 加密/解密結果字符串
* @throws Exception 異常
*/
public static byte[] rsa(byte[] data, String string, @RSAType int type) throws Exception {
byte[] keyBytes = Base64.decode(string, Base64.DEFAULT);
Key key;
KeyFactory keyFactory = getKeyFactory();
if (type == RSA_PUBLIC_ENCRYPT || type == RSA_PUBLIC_DECRYPT) {
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
key = keyFactory.generatePublic(x509KeySpec);
} else {
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
key = keyFactory.generatePrivate(pkcs8KeySpec);
}
// 對數據加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段加密
if (type == RSA_PUBLIC_ENCRYPT || type == RSA_PRIVATE_ENCRYPT) {
cipher.init(Cipher.ENCRYPT_MODE, key);
while (inputLen - offSet > 0) {
if (inputLen - offSet > 117) {
cache = cipher.doFinal(data, offSet, 117);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
out.flush();
i++;
offSet = i * 117;
}
} else {
cipher.init(Cipher.DECRYPT_MODE, key);
while (inputLen - offSet > 0) {
if (inputLen - offSet > 128) {
cache = cipher.doFinal(data, offSet, 128);
// 當最前面的數據是0，解密工具會錯誤的認爲這是padding，因此導致長度不正確
if (cache.length < 117) {
byte[] temp = new byte[117];
System.arraycopy(cache, 0, temp, 117 - cache.length, cache.length);
cache = temp;
}
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
out.flush();
i++;
offSet = i * 128;
}
}
byte[] result = out.toByteArray();
out.close();
return result;
}
}
MD5
/**
* MD5 工具類
*/
public class MD5Util {
/**
* MD5加密
*
* @param string 加密字符串
* @return 加密結果字符串
* @see #md5(String, String)
*/
public static String md5(@NonNull String string) {
return TextUtils.isEmpty(string) ? "" : md5(string, "");
}
/**
* MD5加密(加鹽)
*
* @param string 加密字符串
* @param slat 加密鹽值key
* @return 加密結果字符串
*/
public static String md5(@NonNull String string, String slat) {
if (TextUtils.isEmpty(string)) return "";
try {
MessageDigest md5 = MessageDigest.getInstance("MD5");
byte[] bytes = md5.digest((string + slat).getBytes());
String result = "";
for (byte b : bytes) {
String temp = Integer.toHexString(b & 0xff);
if (temp.length() == 1) {
temp = "0" + temp;
}
result += temp;
}
return result;
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
return "";
}
/**
* MD5加密(多次)
*
* @param string 加密字符串
* @param times 重複加密次數
* @return 加密結果字符串
*/
public static String md5(@NonNull String string, int times) {
if (TextUtils.isEmpty(string)) return "";
String md5 = string;
for (int i = 0; i < times; i++) md5 = md5(md5);
return md5;
}
/**
* MD5加密(文件)
* 可用於文件校驗。
*
* @param file 加密文件
* @return md5 數值
*/
public static String md5(@NonNull File file) {
if (!file.isFile()) {
return "";
}
MessageDigest digest = null;
FileInputStream in = null;
byte buffer[] = new byte[1024];
int len;
try {
digest = MessageDigest.getInstance("MD5");
in = new FileInputStream(file);
while ((len = in.read(buffer, 0, 1024)) != -1) {
digest.update(buffer, 0, len);
}
} catch (Exception e) {
e.printStackTrace();
return "";
}finally {
CloseUtils.close(in);
}
BigInteger bigInt = new BigInteger(1, digest.digest());
return bigInt.toString(16);
}
}
SHA
/**
* SHA 工具類
*/
public class SHAUtil {
public final static String SHA224 = "sha-224";
public final static String SHA256 = "sha-256";
public final static String SHA384 = "sha-384";
public final static String SHA512 = "sha-512";
@StringDef({SHA224, SHA256, SHA384, SHA512})
@interface SHAType {}
/**
* Sha加密
*
* @param string 加密字符串
* @param type 加密類型 ：{@link #SHA224}，{@link #SHA256}，{@link #SHA384}，{@link #SHA512}
* @return SHA加密結果字符串
*/
public static String sha(String string, @Nullable @SHAType String type) {
if (TextUtils.isEmpty(string)) return "";
if (TextUtils.isEmpty(type)) type = SHA256;
try {
MessageDigest md5 = MessageDigest.getInstance(type);
byte[] bytes = md5.digest((string).getBytes());
String result = "";
for (byte b : bytes) {
String temp = Integer.toHexString(b & 0xff);
if (temp.length() == 1) {
temp = "0" + temp;
}
result += temp;
}
return result;
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
return "";
}
}
GZip
public class GzipUtils {
/**
* 字符串的壓縮
*
* @param str 待壓縮的字符串
*
* @return 返回壓縮後的字符串
*/
public static String compress(String str) {
if (null == str || str.length() <= 0) {
return "";
}
ByteArrayOutputStream out = null;
GZIPOutputStream gzip = null;
try {
// 創建一個新的 byte 數組輸出流
out = new ByteArrayOutputStream();
// 使用默認緩衝區大小創建新的輸出流
gzip = new GZIPOutputStream(out);
// 將 b.length 個字節寫入此輸出流
gzip.write(str.getBytes());
gzip.close();
// 使用指定的 charsetName，通過解碼字節將緩衝區內容轉換爲字符串
return out.toString("UTF-8");
} catch (IOException exception) {
exception.printStackTrace();
} finally {
if (out != null) {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (gzip != null) {
try {
gzip.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return "";
}
/**
* 字符串的解壓
*
* @param str 對字符串解壓
*
* @return 返回解壓縮後的字符串
*/
public static String unCompress(String str) {
if (null == str || str.length() <= 0) {
return str;
}
return unCompress(str);
}
/**
* 字符串的解壓
*
* @param str 對字符串解壓
*
* @return 返回解壓縮後的字符串
*/
public static String unCompress(byte[] str) {
if (null == str || str.length <= 0) {
return "";
}
ByteArrayOutputStream out = null;
GZIPInputStream gzip = null;
try {
// 創建一個新的 byte 數組輸出流
out = new ByteArrayOutputStream();
// 創建一個 ByteArrayInputStream，使用 buf 作爲其緩衝區數組
ByteArrayInputStream in = new ByteArrayInputStream(str);
// 使用默認緩衝區大小創建新的輸入流
gzip = new GZIPInputStream(in);
byte[] buffer = new byte[256];
int n = 0;
// 將未壓縮數據讀入字節數組
while ((n = gzip.read(buffer)) >= 0) {
// 將指定 byte 數組中從偏移量 off 開始的 len 個字節寫入此 byte數組輸出流
out.write(buffer, 0, n);
}
// 使用指定的 charsetName，通過解碼字節將緩衝區內容轉換爲字符串
return out.toString("UTF-8");
} catch (IOException exception) {
exception.printStackTrace();
} finally {
if (out != null) {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (gzip != null) {
try {
gzip.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return "";
}
public static boolean isGzip(byte[] dataArr) {
if (dataArr == null || dataArr.length <= 0) {
return false;
}
int b0 = dataArr[0];
int b1 = dataArr[1];
int b = ((b1 & 0xFF) << 8 | b0);
return b == GZIPInputStream.GZIP_MAGIC;
}
}
加解密中用到的工具類
- BaseUtils
public class BaseUtils {
/**
* 二進位組轉十六進制字符串
*
* @param buf 二進位組
* @return 十六進制字符串
*/
public static String parseByte2HexStr(byte buf[]) {
StringBuilder sb = new StringBuilder();
for (byte b : buf) {
String hex = Integer.toHexString(b & 0xFF);
if (hex.length() == 1) {
hex = '0' + hex;
}
sb.append(hex.toUpperCase());
}
return sb.toString();
}
/**
* 十六進制字符串轉二進位組
*
* @param hexStr 十六進制字符串
* @return 二進位組
*/
public static byte[] parseHexStr2Byte(String hexStr) {
if (hexStr.length() < 1) return null;
byte[] result = new byte[hexStr.length() / 2];
for (int i = 0; i < hexStr.length() / 2; i++) {
int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
result[i] = (byte) (high * 16 + low);
}
return result;
}
}
- Base64
/**
* Utilities for encoding and decoding the Base64 representation of
* binary data. See RFCs <a
* href="http://www.ietf.org/rfc/rfc2045.txt">2045</a> and <a
* href="http://www.ietf.org/rfc/rfc3548.txt">3548</a>.
*/
public class Base64 {
/**
* Default values for encoder/decoder flags.
*/
public static final int DEFAULT = 0;
/**
* Encoder flag bit to omit the padding '=' characters at the end
* of the output (if any).
*/
public static final int NO_PADDING = 1;
/**
* Encoder flag bit to omit all line terminators (i.e., the output
* will be on one long line).
*/
public static final int NO_WRAP = 2;
/**
* Encoder flag bit to indicate lines should be terminated with a
* CRLF pair instead of just an LF. Has no effect if {@code
* NO_WRAP} is specified as well.
*/
public static final int CRLF = 4;
/**
* Encoder/decoder flag bit to indicate using the "URL and
* filename safe" variant of Base64 (see RFC 3548 section 4) where
* {@code -} and {@code _} are used in place of {@code +} and
* {@code /}.
*/
public static final int URL_SAFE = 8;
/**
* Flag to pass to {@link Base64OutputStream} to indicate that it
* should not close the output stream it is wrapping when it
* itself is closed.
*/
public static final int NO_CLOSE = 16;
// --------------------------------------------------------
// shared code
// --------------------------------------------------------
/* package */ static abstract class Coder {
public byte[] output;
public int op;
/**
* Encode/decode another block of input data. this.output is
* provided by the caller, and must be big enough to hold all
* the coded data. On exit, this.opwill be set to the length
* of the coded data.
*
* @param finish true if this is the final call to process for
* this object. Will finalize the coder state and
* include any final bytes in the output.
* @return true if the input so far is good; false if some
* error has been detected in the input stream..
*/
public abstract boolean process(byte[] input, int offset, int len, boolean finish);
/**
* @return the maximum number of bytes a call to process()
* could produce for the given number of input bytes. This may
* be an overestimate.
*/
public abstract int maxOutputSize(int len);
}
// --------------------------------------------------------
// decoding
// --------------------------------------------------------
/**
* Decode the Base64-encoded data in input and return the data in
* a new byte array.
* <p>
* <p>The padding '=' characters at the end are considered optional, but
* if any are present, there must be the correct number of them.
*
* @param str the input String to decode, which is converted to
* bytes using the default charset
* @param flags controls certain features of the decoded output.
* Pass {@code DEFAULT} to decode standard Base64.
* @throws IllegalArgumentException if the input contains
* incorrect padding
*/
public static byte[] decode(String str, int flags) {
return decode(str.getBytes(), flags);
}
/**
* Decode the Base64-encoded data in input and return the data in
* a new byte array.
* <p>
* <p>The padding '=' characters at the end are considered optional, but
* if any are present, there must be the correct number of them.
*
* @param input the input array to decode
* @param flags controls certain features of the decoded output.
* Pass {@code DEFAULT} to decode standard Base64.
* @throws IllegalArgumentException if the input contains
* incorrect padding
*/
public static byte[] decode(byte[] input, int flags) {
return decode(input, 0, input.length, flags);
}
/**
* Decode the Base64-encoded data in input and return the data in
* a new byte array.
* <p>
* <p>The padding '=' characters at the end are considered optional, but
* if any are present, there must be the correct number of them.
*
* @param input the data to decode
* @param offset the position within the input array at which to start
* @param len the number of bytes of input to decode
* @param flags controls certain features of the decoded output.
* Pass {@code DEFAULT} to decode standard Base64.
* @throws IllegalArgumentException if the input contains
* incorrect padding
*/
public static byte[] decode(byte[] input, int offset, int len, int flags) {
// Allocate space for the most data the input could represent.
// (It could contain less if it contains whitespace, etc.)
Decoder decoder = new Decoder(flags, new byte[len * 3 / 4]);
if (!decoder.process(input, offset, len, true)) {
throw new IllegalArgumentException("bad base-64");
}
// Maybe we got lucky and allocated exactly enough output space.
if (decoder.op == decoder.output.length) {
return decoder.output;
}
// Need to shorten the array, so allocate a new one of the
// right size and copy.
byte[] temp = new byte[decoder.op];
System.arraycopy(decoder.output, 0, temp, 0, decoder.op);
return temp;
}
/* package */ static class Decoder extends Coder {
/**
* Lookup table for turning bytes into their position in the
* Base64 alphabet.
*/
private static final int DECODE[] = {
-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, -2, -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,
-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, -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, -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,
};
/**
* Decode lookup table for the "web safe" variant (RFC 3548
* sec. 4) where - and _ replace + and /.
*/
private static final int DECODE_WEBSAFE[] = {
-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, -1, -1, 62, -1, -1,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -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, 63,
-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,
-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, -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, -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,
};
/**
* Non-data values in the DECODE arrays.
*/
private static final int SKIP = -1;
private static final int EQUALS = -2;
/**
* States 0-3 are reading through the next input tuple.
* State 4 is having read one '=' and expecting exactly
* one more.
* State 5 is expecting no more data or padding characters
* in the input.
* State 6 is the error state; an error has been detected
* in the input and no future input can "fix" it.
*/
private int state; // state number (0 to 6)
private int value;
final private int[] alphabet;
public Decoder(int flags, byte[] output) {
this.output = output;
alphabet = ((flags & URL_SAFE) == 0) ? DECODE : DECODE_WEBSAFE;
state = 0;
value = 0;
}
/**
* @return an overestimate for the number of bytes {@code
* len} bytes could decode to.
*/
public int maxOutputSize(int len) {
return len * 3 / 4 + 10;
}
/**
* Decode another block of input data.
*
* @return true if the state machine is still healthy. false if
* bad base-64 data has been detected in the input stream.
*/
public boolean process(byte[] input, int offset, int len, boolean finish) {
if (this.state == 6) return false;
int p = offset;
len += offset;
// Using local variables makes the decoder about 12%
// faster than if we manipulate the member variables in
// the loop. (Even alphabet makes a measurable
// difference, which is somewhat surprising to me since
// the member variable is final.)
int state = this.state;
int value = this.value;
int op = 0;
final byte[] output = this.output;
final int[] alphabet = this.alphabet;
while (p < len) {
// Try the fast path: we're starting a new tuple and the
// next four bytes of the input stream are all data
// bytes. This corresponds to going through states
// 0-1-2-3-0. We expect to use this method for most of
// the data.
//
// If any of the next four bytes of input are non-data
// (whitespace, etc.), value will end up negative. (All
// the non-data values in decode are small negative
// numbers, so shifting any of them up and or'ing them
// together will result in a value with its top bit set.)
//
// You can remove this whole block and the output should
// be the same, just slower.
if (state == 0) {
while (p + 4 <= len &&
(value = ((alphabet[input[p] & 0xff] << 18) |
(alphabet[input[p + 1] & 0xff] << 12) |
(alphabet[input[p + 2] & 0xff] << 6) |
(alphabet[input[p + 3] & 0xff]))) >= 0) {
output[op + 2] = (byte) value;
output[op + 1] = (byte) (value >> 8);
output[op] = (byte) (value >> 16);
op += 3;
p += 4;
}
if (p >= len) break;
}
// The fast path isn't available -- either we've read a
// partial tuple, or the next four input bytes aren't all
// data, or whatever. Fall back to the slower state
// machine implementation.
int d = alphabet[input[p++] & 0xff];
switch (state) {
case 0:
if (d >= 0) {
value = d;
++state;
} else if (d != SKIP) {
this.state = 6;
return false;
}
break;
case 1:
if (d >= 0) {
value = (value << 6) | d;
++state;
} else if (d != SKIP) {
this.state = 6;
return false;
}
break;
case 2:
if (d >= 0) {
value = (value << 6) | d;
++state;
} else if (d == EQUALS) {
// Emit the last (partial) output tuple;
// expect exactly one more padding character.
output[op++] = (byte) (value >> 4);
state = 4;
} else if (d != SKIP) {
this.state = 6;
return false;
}
break;
case 3:
if (d >= 0) {
// Emit the output triple and return to state 0.
value = (value << 6) | d;
output[op + 2] = (byte) value;
output[op + 1] = (byte) (value >> 8);
output[op] = (byte) (value >> 16);
op += 3;
state = 0;
} else if (d == EQUALS) {
// Emit the last (partial) output tuple;
// expect no further data or padding characters.
output[op + 1] = (byte) (value >> 2);
output[op] = (byte) (value >> 10);
op += 2;
state = 5;
} else if (d != SKIP) {
this.state = 6;
return false;
}
break;
case 4:
if (d == EQUALS) {
++state;
} else if (d != SKIP) {
this.state = 6;
return false;
}
break;
case 5:
if (d != SKIP) {
this.state = 6;
return false;
}
break;
}
}
if (!finish) {
// We're out of input, but a future call could provide
// more.
this.state = state;
this.value = value;
this.op = op;
return true;
}
// Done reading input. Now figure out where we are left in
// the state machine and finish up.
switch (state) {
case 0:
// Output length is a multiple of three. Fine.
break;
case 1:
// Read one extra input byte, which isn't enough to
// make another output byte. Illegal.
this.state = 6;
return false;
case 2:
// Read two extra input bytes, enough to emit 1 more
// output byte. Fine.
output[op++] = (byte) (value >> 4);
break;
case 3:
// Read three extra input bytes, enough to emit 2 more
// output bytes. Fine.
output[op++] = (byte) (value >> 10);
output[op++] = (byte) (value >> 2);
break;
case 4:
// Read one padding '=' when we expected 2. Illegal.
this.state = 6;
return false;
case 5:
// Read all the padding '='s we expected and no more.
// Fine.
break;
}
this.state = state;
this.op = op;
return true;
}
}
// --------------------------------------------------------
// encoding
// --------------------------------------------------------
/**
* Base64-encode the given data and return a newly allocated
* String with the result.
*
* @param input the data to encode
* @param flags controls certain features of the encoded output.
* Passing {@code DEFAULT} results in output that
* adheres to RFC 2045.
*/
public static String encodeToString(byte[] input, int flags) {
try {
return new String(encode(input, flags), "US-ASCII");
} catch (UnsupportedEncodingException e) {
// US-ASCII is guaranteed to be available.
throw new AssertionError(e);
}
}
/**
* Base64-encode the given data and return a newly allocated
* String with the result.
*
* @param input the data to encode
* @param offset the position within the input array at which to
* start
* @param len the number of bytes of input to encode
* @param flags controls certain features of the encoded output.
* Passing {@code DEFAULT} results in output that
* adheres to RFC 2045.
*/
public static String encodeToString(byte[] input, int offset, int len, int flags) {
try {
return new String(encode(input, offset, len, flags), "US-ASCII");
} catch (UnsupportedEncodingException e) {
// US-ASCII is guaranteed to be available.
throw new AssertionError(e);
}
}
/**
* Base64-encode the given data and return a newly allocated
* byte[] with the result.
*
* @param input the data to encode
* @param flags controls certain features of the encoded output.
* Passing {@code DEFAULT} results in output that
* adheres to RFC 2045.
*/
public static byte[] encode(byte[] input, int flags) {
return encode(input, 0, input.length, flags);
}
/**
* Base64-encode the given data and return a newly allocated
* byte[] with the result.
*
* @param input the data to encode
* @param offset the position within the input array at which to
* start
* @param len the number of bytes of input to encode
* @param flags controls certain features of the encoded output.
* Passing {@code DEFAULT} results in output that
* adheres to RFC 2045.
*/
public static byte[] encode(byte[] input, int offset, int len, int flags) {
Encoder encoder = new Encoder(flags, null);
// Compute the exact length of the array we will produce.
int output_len = len / 3 * 4;
// Account for the tail of the data and the padding bytes, if any.
if (encoder.do_padding) {
if (len % 3 > 0) {
output_len += 4;
}
} else {
switch (len % 3) {
case 0: break;
case 1: output_len += 2; break;
case 2: output_len += 3; break;
}
}
// Account for the newlines, if any.
if (encoder.do_newline && len > 0) {
output_len += (((len - 1) / (3 * Encoder.LINE_GROUPS)) + 1) *
(encoder.do_cr ? 2 : 1);
}
encoder.output = new byte[output_len];
encoder.process(input, offset, len, true);
assert encoder.op == output_len;
return encoder.output;
}
/* package */ static class Encoder extends Coder {
/**
* Emit a new line every this many output tuples. Corresponds to
* a 76-character line length (the maximum allowable according to
* <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>).
*/
public static final int LINE_GROUPS = 19;
/**
* Lookup table for turning Base64 alphabet positions (6 bits)
* into output bytes.
*/
private static final byte ENCODE[] = {
'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', '+', '/',
};
/**
* Lookup table for turning Base64 alphabet positions (6 bits)
* into output bytes.
*/
private static final byte ENCODE_WEBSAFE[] = {
'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', '-', '_',
};
final private byte[] tail;
/* package */ int tailLen;
private int count;
final public boolean do_padding;
final public boolean do_newline;
final public boolean do_cr;
final private byte[] alphabet;
public Encoder(int flags, byte[] output) {
this.output = output;
do_padding = (flags & NO_PADDING) == 0;
do_newline = (flags & NO_WRAP) == 0;
do_cr = (flags & CRLF) != 0;
alphabet = ((flags & URL_SAFE) == 0) ? ENCODE : ENCODE_WEBSAFE;
tail = new byte[2];
tailLen = 0;
count = do_newline ? LINE_GROUPS : -1;
}
/**
* @return an overestimate for the number of bytes {@code
* len} bytes could encode to.
*/
public int maxOutputSize(int len) {
return len * 8 / 5 + 10;
}
public boolean process(byte[] input, int offset, int len, boolean finish) {
// Using local variables makes the encoder about 9% faster.
final byte[] alphabet = this.alphabet;
final byte[] output = this.output;
int op = 0;
int count = this.count;
int p = offset;
len += offset;
int v = -1;
// First we need to concatenate the tail of the previous call
// with any input bytes available now and see if we can empty
// the tail.
switch (tailLen) {
case 0:
// There was no tail.
break;
case 1:
if (p + 2 <= len) {
// A 1-byte tail with at least 2 bytes of
// input available now.
v = ((tail[0] & 0xff) << 16) |
((input[p++] & 0xff) << 8) |
(input[p++] & 0xff);
tailLen = 0;
} ;
break;
case 2:
if (p + 1 <= len) {
// A 2-byte tail with at least 1 byte of input.
v = ((tail[0] & 0xff) << 16) |
((tail[1] & 0xff) << 8) |
(input[p++] & 0xff);
tailLen = 0;
}
break;
}
if (v != -1) {
output[op++] = alphabet[(v >> 18) & 0x3f];
output[op++] = alphabet[(v >> 12) & 0x3f];
output[op++] = alphabet[(v >> 6) & 0x3f];
output[op++] = alphabet[v & 0x3f];
if (--count == 0) {
if (do_cr) output[op++] = '\r';
output[op++] = '\n';
count = LINE_GROUPS;
}
}
// At this point either there is no tail, or there are fewer
// than 3 bytes of input available.
// The main loop, turning 3 input bytes into 4 output bytes on
// each iteration.
while (p + 3 <= len) {
v = ((input[p] & 0xff) << 16) |
((input[p + 1] & 0xff) << 8) |
(input[p + 2] & 0xff);
output[op] = alphabet[(v >> 18) & 0x3f];
output[op + 1] = alphabet[(v >> 12) & 0x3f];
output[op + 2] = alphabet[(v >> 6) & 0x3f];
output[op + 3] = alphabet[v & 0x3f];
p += 3;
op += 4;
if (--count == 0) {
if (do_cr) output[op++] = '\r';
output[op++] = '\n';
count = LINE_GROUPS;
}
}
if (finish) {
// Finish up the tail of the input. Note that we need to
// consume any bytes in tail before any bytes
// remaining in input; there should be at most two bytes
// total.
if (p - tailLen == len - 1) {
int t = 0;
v = ((tailLen > 0 ? tail[t++] : input[p++]) & 0xff) << 4;
tailLen -= t;
output[op++] = alphabet[(v >> 6) & 0x3f];
output[op++] = alphabet[v & 0x3f];
if (do_padding) {
output[op++] = '=';
output[op++] = '=';
}
if (do_newline) {
if (do_cr) output[op++] = '\r';
output[op++] = '\n';
}
} else if (p - tailLen == len - 2) {
int t = 0;
v = (((tailLen > 1 ? tail[t++] : input[p++]) & 0xff) << 10) |
(((tailLen > 0 ? tail[t++] : input[p++]) & 0xff) << 2);
tailLen -= t;
output[op++] = alphabet[(v >> 12) & 0x3f];
output[op++] = alphabet[(v >> 6) & 0x3f];
output[op++] = alphabet[v & 0x3f];
if (do_padding) {
output[op++] = '=';
}
if (do_newline) {
if (do_cr) output[op++] = '\r';
output[op++] = '\n';
}
} else if (do_newline && op > 0 && count != LINE_GROUPS) {
if (do_cr) output[op++] = '\r';
output[op++] = '\n';
}
assert tailLen == 0;
assert p == len;
} else {
// Save the leftovers in tail to be consumed on the next
// call to encodeInternal.
if (p == len - 1) {
tail[tailLen++] = input[p];
} else if (p == len - 2) {
tail[tailLen++] = input[p];
tail[tailLen++] = input[p + 1];
}
}
this.op = op;
this.count = count;
return true;
}
}
private Base64() { } // don't instantiate
}
- CloseUtils
public class CloseUtils {
public static void close(Closeable closeable) {
if (null == closeable) return;
try {
closeable.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
- TextUtils
public class TextUtils {
public static boolean isEmpty(String str){
return null == str || str.isEmpty();
}
}