Java实现的utf8，gbk，unicode编码相互转换的代码

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();
}

}
//转自: http://www.sharejs.com/codes/java/5422[/code]