htmlfilter.java

JavaWeb高级特性书中源代码

package util;
public final class HTMLFilter
{	
	public static String filter(String message)
	{
		if (message == null)
		{
			return (null);
		}
		char content[] = new char[message.length()];
		message.getChars(0, message.length(), content, 0);
		StringBuffer result = new StringBuffer(content.length + 50);
		for (int i = 0; i < content.length; i++)
		{
			switch (content[i])
			{
				case '<':
					result.append("&lt;");
					break;
				case '>':
					result.append("&gt;");
					break;
				case '&':
					result.append("&amp;");
					break;
				case '"':
					result.append("&quot;");
					break;
				default:
					result.append(content[i]);
			}
		}
		return (result.toString());
	}
}