Filter进行权限控制

import javax.servlet.Filter; import javax.servlet.ServletException; import javax.servlet.FilterConfig; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.FilterChain; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpSession; import java.io.IOException; public class LoginFilter implements Filter{ public void init(FilterConfig filterConfig) throws ServletException{ } public void destroy(){ } public void doFilter(ServletRequest request1, ServletResponse response, FilterChain chain) throws IOException, ServletException{ HttpServletRequest request = ( HttpServletRequest )request1; HttpSession session = request.getSession(); String str = (String)session.getAttribute("login"); if("ok".equals(str)){ chain.doFilter(request , response); }else{ String query = request.getQueryString(); String uri1 = request.getRequestURI() ; String path; if(query != null){ path = uri1+"?"+query; }else{ path = uri1; } System.out.println(path); request.setAttribute("path",path); request.getRequestDispatcher("/login.jsp").forward(request1,response); } } }