package com.jarvis.base.util;
import java.io.*;
/**
* @Title: Base64Util.java
* @Package com.jarvis.base.util
* @Description:Base64工具类
* @author Jack
* @date 2017年9月2日 下午5:10:32
* @version V1.0
*/
public final class Base64Util
{
private static final int BASELENGTH = 255;
private static final int LOOKUPLENGTH = 64;
private static final int TWENTYFOURBITGROUP = 24;
private static final int EIGHTBIT = 8;
private static final int SIXTEENBIT = 16;
// private static final int SIXBIT = 6;
private static final int FOURBYTE = 4;
// private static final int TWOBYTE = 2;
private static final int SIGN = -128;
private static final byte PAD = (byte) '=';
private static byte[] base64Alphabet = new byte[BASELENGTH];
private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];
static
{
for (int i = 0; i < BASELENGTH; i++)
{
base64Alphabet[i] = -1;
}
for (int i = 'Z'; i >= 'A'; i--)
{
base64Alphabet[i] = (byte) (i - 'A');
}
for (int i = 'z'; i >= 'a'; i--)
{
base64Alphabet[i] = (byte) (i - 'a' + 26);
}
for (int i = '9'; i >= '0'; i--)
{
base64Alphabet[i] = (byte) (i - '0' + 52);
}
base64Alphabet['+'] = 62;
base64Alphabet['/'] = 63;
for (int i = 0; i <= 25; i++)
{
lookUpBase64Alphabet[i] = (byte) ('A' + i);
}
for (int i = 26, j = 0; i <= 51; i++, j++)
{
lookUpBase64Alphabet[i] = (byte) ('a' + j);
}
for (int i = 52, j = 0; i <= 61; i++, j++)
{
lookUpBase64Alphabet[i] = (byte) ('0' + j);
}
lookUpBase64Alphabet[62] = (byte) '+';
lookUpBase64Alphabet[63] = (byte) '/';
}
public static boolean isBase64(String isValidString)
{
return isArrayByteBase64(isValidString.getBytes());
}
public static boolean isBase64(byte octect)
{
// shall we ignore white space? JEFF??
return (octect == PAD || base64Alphabet[octect] != -1);
}
public static boolean isArrayByteBase64(byte[] arrayOctect)
{
int length = arrayOctect.length;
if (length == 0)
{
// shouldn't a 0 length array be valid base64 data?
// return false;
return true;
}
for (int i = 0; i < length; i++)
{
if (!isBase64(arrayOctect[i]))
{
return false;
}
}
return true;
}
/**
* Encode String object;
*
* @param src String object to be encoded.
* @return encoded String;
*/
public static String encodeString(String src)
{
return encode(src);
}
public static String encodeBytes(byte[] src)
{
if (src == null || src.length == 0) {
return null;
}
byte[] bytes = encode(src);
return new String(bytes);
}
/**
* Encode String object;
*
* @param src String object to be encoded.
* @return encoded String;
*/
public static String encode(String src)
{
String target = null;
if (src != null)
{
byte[] bts1 = src.getBytes();
byte[] bts2 = encode(bts1);
if (bts2 != null)
{
target = new String(bts2);
}
}
return target;
}
/**
* Encodes hex octects into Base64.
*
* @param binaryData Array containing binary data to encode.
* @return Base64-encoded data.
*/
public static byte[] encode(byte[] binaryData)
{
int lengthDataBits = binaryData.length * EIGHTBIT;
int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
byte encodedData[] = null;
if (fewerThan24bits != 0)
{
// data not divisible by 24 bit
encodedData = new byte[(numberTriplets + 1) * 4];
}
else
{
// 16 or 8 bit
encodedData = new byte[numberTriplets * 4];
}
byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;
int encodedIndex = 0;
int dataIndex = 0;
int i = 0;
for (i = 0; i < numberTriplets; i++)
{
dataIndex = i * 3;
b1 = binaryData[dataIndex];
b2 = binaryData[dataIndex + 1];
b3 = binaryData[dataIndex + 2];
l = (byte) (b2 & 0x0f);
k = (byte) (b1 & 0x03);
encodedIndex = i * 4;
byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc);
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)];
encodedData[encodedIndex + 2] = lookUpBase64Alphabet[(l << 2) | val3];
encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];
}
// form integral number of 6-bit groups
dataIndex = i * 3;
encodedIndex = i * 4;
if (fewerThan24bits == EIGHTBIT)
{
b1 = binaryData[dataIndex];
k = (byte) (b1 & 0x03);
byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];
encodedData[encodedIndex + 2] = PAD;
encodedData[encodedIndex + 3] = PAD;
}
else if (fewerThan24bits == SIXTEENBIT)
{
b1 = binaryData[dataIndex];
b2 = binaryData[dataIndex + 1];
l = (byte) (b2 & 0x0f);
k = (byte) (b1 & 0x03);
byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)];
encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];
encodedData[encodedIndex + 3] = PAD;
}
return encodedData;
}
public static String decode(String src)
{
String target = null;
if (src != null)
{
byte[] bts1 = src.getBytes();
byte[] bts2 = decode(bts1);
if (bts2 != null)
{
target = new String(bts2);
}
}
return target;
}
public static String decode(String src, String charSet) throws UnsupportedEncodingException
{
String target = null;
if (src != null)
{
byte[] bts1 = src.getBytes();
byte[] bts2 = decode(bts1);
if (bts2 != null)
{
target = new String(bts2, charSet);
}
}
return target;
}
/**
* Decodes Base64 data into octects
*
* @param base64Data Byte array containing Base64 data
* @return Array containing decoded data.
*/
public static byte[] decode(byte[] base64Data)
{
// handle the edge case, so we don't have to worry about it later
if (base64Data.length == 0)
{
return null;
}
int numberQuadruple = base64Data.length / FOURBYTE;
byte decodedData[] = null;
byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;
// Throw away anything not in base64Data
int encodedIndex = 0;
int dataIndex = 0;
{
// this sizes the output array properly - rlw
int lastData = base64Data.length;
// ignore the '=' padding
while (base64Data[lastData - 1] == PAD)
{
if (--lastData == 0)
{
return new byte[0];
}
}
decodedData = new byte[lastData - numberQuadruple];
}
for (int i = 0; i < numberQuadruple; i++)
{
dataIndex = i * 4;
marker0 = base64Data[dataIndex + 2];
marker1 = base64Data[dataIndex + 3];
b1 = base64Alphabet[base64Data[dataIndex]];
b2 = base64Alphabet[base64Data[dataIndex + 1]];
if (marker0 != PAD && marker1 != PAD)
{
// No PAD e.g 3cQl
b3 = base64Alphabet[marker0];
b4 = base64Alphabet[marker1];
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
decodedData[encodedIndex + 1] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
decodedData[encodedIndex + 2] = (byte) (b3 << 6 | b4);
}
else if (marker0 == PAD)
{
// Two PAD e.g. 3c[Pad][Pad]
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
}
else if (marker1 == PAD)
{
// One PAD e.g. 3cQ[Pad]
b3 = base64Alphabet[marker0];
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
decodedData[encodedIndex + 1] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
}
encodedIndex += 3;
}
return decodedData;
}
/**
* 隐藏工具类的构造方法
*/
protected Base64Util()
{
throw new UnsupportedOperationException();
}
/**
* 文件读取缓冲区大小
*/
private static final int CACHE_SIZE = 1024;
/** *//**
* <p>
* BASE64字符串解码为二进制数据
* </p>
*
* @param base64
* @return
* @throws Exception
*/
public static byte[] decodeString(String base64) throws Exception {
return Base64Util.decode(base64.getBytes());
}
/** *//**
* <p>
* 二进制数据编码为BASE64字符串
* </p>
*
* @param bytes
* @return
* @throws Exception
*/
public static String encodeByte(byte[] bytes) throws Exception {
return new String(Base64Util.encode(bytes));
}
/** *//**
* <p>
* 将文件编码为BASE64字符串
* </p>
* <p>
* 大文件慎用，可能会导致内存溢出
* </p>
*
* @param filePath 文件绝对路径
* @return
* @throws Exception
*/
public static String encodeFile(String filePath) throws Exception {
byte[] bytes = fileToByte(filePath);
return encodeByte(bytes);
}
/** *//**
* <p>
* BASE64字符串转回文件
* </p>
*
* @param filePath 文件绝对路径
* @param base64 编码字符串
* @throws Exception
*/
public static void decodeToFile(String filePath, String base64) throws Exception {
byte[] bytes = decodeString(base64);
byteArrayToFile(bytes, filePath);
}
/** *//**
* <p>
* 文件转换为二进制数组
* </p>
*
* @param filePath 文件路径
* @return
* @throws Exception
*/
public static byte[] fileToByte(String filePath) throws Exception {
byte[] data = new byte[0];
File file = new File(filePath);
if (file.exists()) {
FileInputStream in = new FileInputStream(file);
ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
in.close();
data = out.toByteArray();
}
return data;
}
/** *//**
* <p>
* 二进制数据写文件
* </p>
*
* @param bytes 二进制数据
* @param filePath 文件生成目录
*/
public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {
InputStream in = new ByteArrayInputStream(bytes);
File destFile = new File(filePath);
if (!destFile.getParentFile().exists()) {
destFile.getParentFile().mkdirs();
}
destFile.createNewFile();
OutputStream out = new FileOutputStream(destFile);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
in.close();
}
}
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