securefilter.java

一个JAVA的小例子 大家不放运行一下 熟悉一下

package com.abc.dl.filters;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

public class SecureFilter implements Filter{

	public void destroy() {	}

	public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException {
		HttpServletRequest request = 
			(HttpServletRequest) arg0;
		
		HttpSession session = request.getSession();
		
		String s = (String) session.getAttribute("login");
		if (s==null) {
			request.getRequestDispatcher("/login.html").forward(arg0, arg1);
			return;
		}
		if (s.equals("true")) {
			arg2.doFilter(arg0, arg1);
		}
		else {
			request.getRequestDispatcher("/login.html").forward(arg0, arg1);
		}	
	}

	public void init(FilterConfig arg0) throws ServletException {}
	
}