Java实现Javascript中的unescape

public static String unescape(String src) {
StringBuffer tmp = new StringBuffer();
tmp.ensureCapacity(src.length());
int lastPos = 0, pos = 0;
char ch;
while (lastPos < src.length()) {
pos = src.indexOf("%", lastPos);
if (pos == lastPos) {
if (src.charAt(pos + 1) == 'u') {
ch = (char) Integer.parseInt(src.substring(pos + 2, pos + 6), 16);
tmp.append(ch);
lastPos = pos + 6;
}
else {
ch = (char) Integer.parseInt(src.substring(pos + 1, pos + 3), 16);
tmp.append(ch);
lastPos = pos + 3;
}
}
else {
if (pos == -1) {
tmp.append(src.substring(lastPos));
lastPos = src.length();
}
else {
tmp.append(src.substring(lastPos, pos));
lastPos = pos;
}
}
}
return tmp.toString();
}