实现asp中htmlencode功能的jsp函数

public static String asHTML(String text) 
{ 
	if (text == null) 
		return ""; 
	StringBuffer results = null; 
	char[] orig = null; 
	int beg = 0, len = text.length(); 
	for (int i = 0; i < len; ++i) 
	{ 
		char c = text.charAt(i); 
		switch (c)
		{ 
			case 0: 
			case '&': 
			case '<': 
			case '>': 
			case '"': 
			if (results == null) 
			{ 
				orig = text.toCharArray(); 
				results = new StringBuffer(len+10); 
			} 
			if (i > beg) 
				results.append(orig, beg, i-beg); 
			beg = i + 1; 
			switch (c) 
			{ 
				default: // case 0: 
					continue; 
				case '&': 
					results.append("&"); 
					break; 
				case '<': 
					results.append("<"); 
					break; 
				case '>': 
					results.append(">"); 
					break; 
				case '"': 
					results.append("""); 
					break; 
			} 
			break; 
		} 
	} 
	if (results == null) 
		return text; 
	results.append(orig, beg, len-beg); 
	return results.toString(); 
}