Java实现Escape

public class EscapeUtil {  
	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 String isoToGB(String src) {
		String strRet = null;
		try {
			strRet = new String(src.getBytes("ISO_8859_1"), "GB2312");
		} catch (Exception e) {

		}
		return strRet;
	}

	public static String isoToUTF(String src) {
		String strRet = null;
		try {
			strRet = new String(src.getBytes("ISO_8859_1"), "UTF-8");
		} catch (Exception e) {

		}
		return strRet;
	}
 
	 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();
		}
}