Java web过滤器验证登录（避免未经登录进入主页）

来源：互联网发布：小贷软件编辑：程序博客网时间：2024/05/16 08:13

1.首先写一个权限过滤filter类,实现Filter接口

 1 import java.io.IOException; 2  3 import javax.servlet.Filter; 4 import javax.servlet.FilterChain; 5 import javax.servlet.FilterConfig; 6 import javax.servlet.ServletException; 7 import javax.servlet.ServletRequest; 8 import javax.servlet.ServletResponse; 9 import javax.servlet.http.HttpServletRequest;10 import javax.servlet.http.HttpServletResponse;11 import javax.servlet.http.HttpSession;12 13 public class LoginFilter implements Filter {14 15     @Override16     public void init(FilterConfig filterConfig) throws ServletException {17         // TODO Auto-generated method stub18 19     }20 21     @Override22     public void doFilter(ServletRequest request, ServletResponse response,23             FilterChain chain) throws IOException, ServletException {24         // 获得在下面代码中要用的request,response,session对象25         HttpServletRequest servletRequest = (HttpServletRequest) request;26         HttpServletResponse servletResponse = (HttpServletResponse) response;27         HttpSession session = servletRequest.getSession();28 29         // 获得用户请求的URI30         String path = servletRequest.getRequestURI();31         //System.out.println(path);32         33         // 从session里取员工工号信息34         String empId = (String) session.getAttribute("empId");35 36         /*创建类Constants.java，里面写的是无需过滤的页面37         for (int i = 0; i < Constants.NoFilter_Pages.length; i++) {38 39             if (path.indexOf(Constants.NoFilter_Pages[i]) > -1) {40                 chain.doFilter(servletRequest, servletResponse);41                 return;42             }43         }*/44         45         // 登陆页面无需过滤46         if(path.indexOf("/login.jsp") > -1) {47             chain.doFilter(servletRequest, servletResponse);48             return;49         }50 51         // 判断如果没有取到员工信息,就跳转到登陆页面52         if (empId == null || "".equals(empId)) {53             // 跳转到登陆页面54             servletResponse.sendRedirect("/JingXing_OA/login.jsp");55         } else {56             // 已经登陆,继续此次请求57             chain.doFilter(request, response);58         }59 60     }61 62     @Override63     public void destroy() {64         // TODO Auto-generated method stub65 66     }67 68 }

2.然后在web.xml里配置需要登陆权限验证的JSP文件:
a.如果是某个具体的JSP文件(如a.jsp)需要登陆验证

 1 <!-- 配置登陆过滤器 --> 2 <filter> 3         <filter-name>login</filter-name> 4         <filter-class>com.jingxing.oa.filter.LoginFilter</filter-class> 5     </filter> 6  7     <filter-mapping> 8         <filter-name>login</filter-name> 9         <url-pattern>/*</url-pattern>10 </filter-mapping>

b.如果是某一个目录(如a/目录)整个目录下的文件都需要登陆验证:

 1 <!-- 配置登陆过滤器 --> 2     <filter> 3         <filter-name>login</filter-name> 4         <filter-class>com.jingxing.oa.filter.LoginFilter</filter-class> 5     </filter> 6  7     <filter-mapping> 8         <filter-name>login</filter-name> 9         <url-pattern>/a/*</url-pattern>10     </filter-mapping>

1 1