JAVA 转义函数：跳过转义字符

package escape;
//java版本的escape和unescape函数
class EscapeUnescape {
public static String escape(String src) {
int i;
char j;
StringBuffer tmp = new StringBuffer();
tmp.ensureCapacity(src.length() * 6);
for (i = 0; i < src.length(); i++) {
j = src.charAt(i);
if (Character.isDigit(j) || Character.isLowerCase(j)
|| Character.isUpperCase(j))
tmp.append(j);
else if (j < 256) {
tmp.append("%");
if (j < 16)
tmp.append("0");
tmp.append(Integer.toString(j, 16));
} else {
tmp.append("%u");
tmp.append(Integer.toString(j, 16));
}
}
return tmp.toString();
}
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();
}
public static void main(String[] args) {
String tmp = "~!@#$%^&*()_+|\\=-,./?><;'][{}\"";
System.out.println("testing escape : " + tmp);
tmp = escape(tmp);
System.out.println(tmp);
System.out.println("testing unescape :" + tmp);
System.out.println(unescape(tmp));
}
}

testing escape : ~!@#$%^&*()_+|\=-,./?><;'][{}"
%7e%21%40%23%24%25%5e%26%2a%28%29%5f%2b%7c%5c%3d%2d%2c%2e%2f%3f%3e%3c%3b%27%5d%5b%7b%7d%22
testing unescape :%7e%21%40%23%24%25%5e%26%2a%28%29%5f%2b%7c%5c%3d%2d%2c%2e%2f%3f%3e%3c%3b%27%5d%5b%7b%7d%22
~!@#$%^&*()_+|\=-,./?><;'][{}"