userfilter.java

J2EE平台是一种比较 优秀的开发平台 此为其上一个比较大的案例开发

package UserAdmin;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
 * @version 	1.0
 * @author
 */
public class UserFilter implements Filter {
	/**
	* @see javax.servlet.Filter#void ()
	*/
	public void destroy() {
	}
	/**
	* @see javax.servlet.Filter#void (javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
	*/
	public void doFilter(
		ServletRequest req,
		ServletResponse resp,
		FilterChain chain)
		throws ServletException, IOException {
		
		HttpServletRequest request=(HttpServletRequest)req;
		HttpSession session = request.getSession();
		HttpServletResponse response = (HttpServletResponse) resp;
		String user = (String) session.getAttribute("user");
		boolean iscookie=false;
		Cookie[] cookieArray = request.getCookies();
		for (int i = cookieArray.length - 1; i >= 0; i--) {
			Cookie c = null;
			Cookie cookie = cookieArray[i];
			if (cookie.getName().equals("user")){
				response.addCookie(c);
				iscookie=true;
			}
		}
		if (user == null&&iscookie==false)
			((HttpServletResponse) resp).sendRedirect(
				"./UserAdmin/nologin.jsp");
		chain.doFilter(req, resp);
	}
	/**
	* Method init.
	* @param config
	* @throws javax.servlet.ServletException
	*/
	public void init(FilterConfig config) throws ServletException {
	}
}