jsp防止通过url访问没有权限的页面

用 javax.servlet.Filter

例1、登录验证

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {

HttpServletRequest req = (HttpServletRequest) request;
HttpServletResponse res = (HttpServletResponse) response;

if(req.getSession(true).getAttribute("登录标记")==null){
res.sendRedirect("登陆页面");
return;
} else {
chain.doFilter(request, response);
}
}

<web-app ...>
<filter>
<filter-name>名字随便起</filter-name>
<filter-class>wyf.web.servlet.filter.WangyfPrintFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>这里的名字要与上面的名字一致</filter-name>
<url-pattern>这里填写要保护的路径 * 表示一切(如/user/*)</</url-pattern>
<dispatcher>REQUEST</dispatcher>