java实现UTF-8，GBK，Unicode编码相互转换，代码如下：

public class UTF2GBK {

public String gbk2utf8(String gbk) {

String l_temp = GBK2Unicode(gbk);

l_temp = unicodeToUtf8(l_temp);

return l_temp;

}

public String utf82gbk(String utf) {

String l_temp = utf8ToUnicode(utf);

l_temp = Unicode2GBK(l_temp);

return l_temp;

}

/**

*

* @param str

* @return String

*/

public static String GBK2Unicode(String str) {

StringBuffer result = new StringBuffer();

for (int i = 0; i < str.length(); i++) {

char chr1 = (char) str.charAt(i);

if (!isNeedConvert(chr1)) {

result.append(chr1);

continue;

}

result.append("\\u" + Integer.toHexString((int) chr1));

}

return result.toString();

}

/**

*

* @param dataStr

* @return String

*/

public static String Unicode2GBK(String dataStr) {

int index = 0;

StringBuffer buffer = new StringBuffer();

int li_len = dataStr.length();

while (index < li_len) {

if (index >= li_len - 1

|| !"\\u".equals(dataStr.substring(index, index + 2))) {

buffer.append(dataStr.charAt(index));

index++;

continue;

}

String charStr = "";

charStr = dataStr.substring(index + 2, index + 6);

char letter = (char) Integer.parseInt(charStr, 16);

buffer.append(letter);

index += 6;

}

return buffer.toString();

}

public static boolean isNeedConvert(char para) {

return ((para & (0x00FF)) != para);

}

/**

* utf-8 转unicode

*

* @param inStr

* @return String

*/

public static String utf8ToUnicode(String inStr) {

char[] myBuffer = inStr.toCharArray();

StringBuffer sb = new StringBuffer();

for (int i = 0; i < inStr.length(); i++) {

UnicodeBlock ub = UnicodeBlock.of(myBuffer[i]);

if (ub == UnicodeBlock.BASIC_LATIN) {

sb.append(myBuffer[i]);

} else if (ub == UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS) {

int j = (int) myBuffer[i] - 65248;

sb.append((char) j);

} else {

short s = (short) myBuffer[i];

String hexS = Integer.toHexString(s);

String unicode = "\\u" + hexS;

sb.append(unicode.toLowerCase());

}

}

return sb.toString();

}

/**

*

* @param theString

* @return String

*/

public static String unicodeToUtf8(String theString) {

char aChar;

int len = theString.length();

StringBuffer outBuffer = new StringBuffer(len);

for (int x = 0; x < len;) {

aChar = theString.charAt(x++);

if (aChar == '\\') {

aChar = theString.charAt(x++);

if (aChar == 'u') {

// Read the xxxx

int value = 0;

for (int i = 0; i < 4; i++) {

aChar = theString.charAt(x++);

switch (aChar) {

case '0':

case '1':

case '2':

case '3':

case '4':

case '5':

case '6':

case '7':

case '8':

case '9':

value = (value << 4) + aChar - '0';

break;

case 'a':

case 'b':

case 'c':

case 'd':

case 'e':

case 'f':

value = (value << 4) + 10 + aChar - 'a';

break;

case 'A':

case 'B':

case 'C':

case 'D':

case 'E':

case 'F':

value = (value << 4) + 10 + aChar - 'A';

break;

default:

throw new IllegalArgumentException(

"Malformed \\uxxxx encoding.");

}

}

outBuffer.append((char) value);

} else {

if (aChar == 't')

aChar = '\t';

else if (aChar == 'r')

aChar = '\r';

else if (aChar == 'n')

aChar = '\n';

else if (aChar == 'f')

aChar = '\f';

outBuffer.append(aChar);

}

} else

outBuffer.append(aChar);

}

return outBuffer.toString();

}

}