BASE64加密解密(字符串)

[JAVA] BASE64 使用JDK中的方法编码和解码

BASE64 编码是一种常用的字符编码，在很多地方都会用到。JDK 中提供了非常方便的 BASE64Encoder 和 BASE64Decoder，用它们可以非常方便的完成基于 BASE64 的编码和解码。下面是本人编的两个小的函数，分别用于 BASE64
的编码和解码：

// 将 s 进行 BASE64 编码
public static String getBASE64(String s) {
if (s == null) return null;
return (new sun.misc.BASE64Encoder()).encode( s.getBytes() );
}

// 将 BASE64 编码的字符串 s 进行解码
public static String getFromBASE64(String s) {
if (s == null) return null;
BASE64Decoder decoder = new BASE64Decoder();
try {
byte[] b = decoder.decodeBuffer(s);
return new String(b);
} catch (Exception e) {
return null;
}
}

[ANDROID] BASE64加密解密(字符串)

import java.io.ByteArrayOutputStream;

public class Base64Util {
private static final 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', '+', '/' };

private static byte[] base64DecodeChars = new byte[] { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -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, -1, -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 };

private Base64Util() {
}

/**
* 将字节数组编码为字符串
*
* @param data
*/
public static String encode(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();
}

/**
* 将base64字符串解码为字节数组
*
* @param str
*/
public static byte[] decode(String str) {
byte[] data = str.getBytes();
int len = data.length;
ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
int i = 0;
int b1, b2, b3, b4;

while (i < len) {

/* b1 */
do {
b1 = base64DecodeChars[data[i++]];
} while (i < len && b1 == -1);
if (b1 == -1) {
break;
}

/* b2 */
do {
b2 = base64DecodeChars[data[i++]];
} while (i < len && b2 == -1);
if (b2 == -1) {
break;
}
buf.write((int) ((b1 << 2) | ((b2 & 0x30) >>> 4)));

/* b3 */
do {
b3 = data[i++];
if (b3 == 61) {
return buf.toByteArray();
}
b3 = base64DecodeChars[b3];
} while (i < len && b3 == -1);
if (b3 == -1) {
break;
}
buf.write((int) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));

/* b4 */
do {
b4 = data[i++];
if (b4 == 61) {
return buf.toByteArray();
}
b4 = base64DecodeChars[b4];
} while (i < len && b4 == -1);
if (b4 == -1) {
break;
}
buf.write((int) (((b3 & 0x03) << 6) | b4));
}
return buf.toByteArray();
}
}

[ANDROID] BASE64 编码解码(数据流)

Base64编解码类

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public class Base64 {
private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();

/** Base64 encode the given data */
public static String encode(byte[] data) {
int start = 0;
int len = data.length;
StringBuffer buf = new StringBuffer(data.length * 3 / 2);

int end = len - 3;
int i = start;
int n = 0;

while (i <= end) {
int d = ((((int) data[i]) & 0x0ff) << 16)
| ((((int) data[i + 1]) & 0x0ff) << 8 )
| (((int) data[i + 2]) & 0x0ff);

buf.append(legalChars[(d >> 18) & 63]);
buf.append(legalChars[(d >> 12) & 63]);
buf.append(legalChars[(d >> 6) & 63]);
buf.append(legalChars[d & 63]);

i += 3;

if (n++ >= 14) {
n = 0;
buf.append(" ");
}
}

if (i == start + len - 2) {
int d = ((((int) data[i]) & 0x0ff) << 16 )
| ((((int) data[i + 1]) & 255) << 8 );

buf.append(legalChars[(d >> 18) & 63]);
buf.append(legalChars[(d >> 12) & 63]);
buf.append(legalChars[(d >> 6) & 63]);
buf.append("=");
} else if (i == start + len - 1) {
int d = (((int) data[i]) & 0x0ff) << 16;

buf.append(legalChars[(d >> 18) & 63]);
buf.append(legalChars[(d >> 12) & 63]);
buf.append("==");
}

return buf.toString();
}

private static int decode(char c) {
if (c >= 'A' && c <= 'Z')
return ((int) c) - 65;
else if (c >= 'a' && c <= 'z')
return ((int) c) - 97 + 26;
else if (c >= '0' && c <= '9')
return ((int) c) - 48 + 26 + 26;
else
switch (c) {
case '+':
return 62;
case '/':
return 63;
case '=':
return 0;
default:
throw new RuntimeException("unexpected code: " + c );
}
}

/**
* Decodes the given Base64 encoded String to a new byte array. The byte
* array holding the decoded data is returned.
*/

public static byte[] decode(String s) {

ByteArrayOutputStream bos = new ByteArrayOutputStream();
try {
decode(s, bos);
} catch (IOException e) {
throw new RuntimeException();
}
byte[] decodedBytes = bos.toByteArray();
try {
bos.close();
bos = null;
} catch (IOException ex) {
System.err.println("Error while decoding BASE64: " + ex.toString());
}
return decodedBytes;
}

private static void decode(String s, OutputStream os) throws IOException {
int i = 0;

int len = s.length();

while (true) {
while (i < len && s.charAt(i) <= ' ')
i++;

if (i == len)
break;

int tri = (decode(s.charAt(i)) << 18 )
+ (decode(s.charAt(i + 1)) << 12 )
+ (decode(s.charAt(i + 2)) << 6 )
+ (decode(s.charAt(i + 3)));

os.write((tri >> 16 ) & 255 );
if (s.charAt(i + 2) == '=')
break;
os.write((tri >> 8 ) & 255);
if (s.charAt(i + 3) == '=')
break;
os.write(tri & 255);

i += 4;
}
}
}

调用代码:

private static String inputStream2String(InputStream is) throws IOException{
ByteArrayOutputStream   baos   =   new   ByteArrayOutputStream();
int   i=-1;
while((i=is.read())!=-1){
baos.write(i);
}

baos.flush();
baos.close();
return Base64.encode(baos.toByteArray());

}