servletutil.java

servlet学习代码

package jsp.servlet.util;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;

public class ServletUtil {
	public static String filter(String param){
		
		StringBuffer filtered = new StringBuffer("");
		char c;
		for(int i = 0; i<param.length(); i++){
			 c = param.charAt(i);
			 switch(c){
				 case '>': filtered.append("&gt;"); break;
				 case '<': filtered.append("&lt;"); break;
				 case '"': filtered.append("&quot;"); break;
				 case '&': filtered.append("&amp;"); break;	
				 default:filtered.append(c);
			 }
		}
		return filtered.toString();	
	}
	
	public static int getIntParamater(HttpServletRequest request, 
			String paramName, int defaultValue){
		
		String paramStr = request.getParameter(paramName);
		int paramInt;
		try{
			paramInt = Integer.parseInt(paramStr);
		}catch(NumberFormatException e){
			paramInt = defaultValue;
		}
		return paramInt;		
	}
	
	public static Cookie getCookie(HttpServletRequest request, 
			String cookieName, String defaultValue){
		Cookie[] cookies =  request.getCookies();
		String cookieValue = "";
		if(cookies != null){
			for(int i=0; i<cookies.length; i++){
				if(cookies[i].getName().equals(cookieName)){
					cookieValue = cookies[i].getValue();
				}
			}
		}if(cookieValue.equals("")){
			cookieValue = defaultValue;
		}
		Cookie c = new Cookie(cookieName, cookieValue);;		
		return c;
	}
	
}