Java web过滤器验证登录（避免未经登录进入主页）

Love The Way You Lie 2022-05-10 05:26 195阅读 0赞

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     @Override
    16     public void init(FilterConfig filterConfig) throws ServletException {
    17         // TODO Auto-generated method stub
    18 
    19     }
    20 
    21     @Override
    22     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URI
    30         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     @Override
    63     public void destroy() {
    64         // TODO Auto-generated method stub
    65 
    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

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 
     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>

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