class:
public class SignonFilter implements Filter {
protected FilterConfig filterConfig;
// 过滤处理
public void doFilter(ServletRequest req, ServletResponse res,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest hreq =(HttpServletRequest)req;
HttpServletResponse hres = (HttpServletResponse)res;
HttpSession session = hreq.getSession();
String isLogin = " ";
isLogin = (String) session.getAttribute( "userName ");
//如果已经登陆
if(isLogin!=null){
chain.doFilter(req,res);
//如果未登陆
}else{
hres.sendRedirect( "login.jsp ");
chain.doFilter(req,res);
}
}
//销毁过滤器
public void destroy() {
this.filterConfig=null;
}
//初始化过滤器
public void init(FilterConfig arg0) throws ServletException {
this.filterConfig=arg0;
}
}
web.xml
<filter>
<filter-name> isLogin </filter-name>
<filter-class> com.cdclive.hotel.common.filter.SignonFilter </filter-class>
</filter>
<filter-mapping>
<filter-name> isLogin </filter-name>
<url-pattern> /member/* </url-pattern>
</filter-mapping>
当我登陆member下的一个页面的时候：
java.lang.IllegalStateException
org.apache.coyote.tomcat5.CoyoteResponseFacade.sendRedirect(CoyoteResponseFacade.java:352)
org.apache.jsp.member.accountsManage_jsp._jspService(accountsManage_jsp.java:112)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
com.cdclive.hotel.common.filter.EncodingFilter.doFilter(EncodingFilter.java:39)
com.cdclive.hotel.common.filter.SignonFilter.doFilter(SignonFilter.java:44)
这是为什么 小弟我对过滤器 没研究 大哥大姐们 耐心教一下
------解决方案--------------------
删掉第二个chain.doFilter(req,res);