一个非常简单的登录权限拦截器，具体代码如下：
以下代码是继承OncePerRequestFilter实现登录过滤的代码：
- /**
- *
- * @author geloin
- * @date 2012-4-10 下午2:37:38
- */
- package com.test.spring.filter;
-
- import java.io.IOException;
- import java.io.PrintWriter;
-
- import javax.servlet.FilterChain;
- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
-
- import org.springframework.web.filter.OncePerRequestFilter;
-
- /**
- * 登录过滤
- *
- * @author geloin
- * @date 2012-4-10 下午2:37:38
- */
- public class SessionFilter extends OncePerRequestFilter {
-
- /*
- * (non-Javadoc)
- *
- * @see
- * org.springframework.web.filter.OncePerRequestFilter#doFilterInternal(
- * javax.servlet.http.HttpServletRequest,
- * javax.servlet.http.HttpServletResponse, javax.servlet.FilterChain)
- */
- @Override
- protected void doFilterInternal(HttpServletRequest request,
- HttpServletResponse response, FilterChain filterChain)
- throws ServletException, IOException {
-
- // 不过滤的uri
- String[] notFilter = new String[] { "login.html", "index.html" };
-
- // 请求的uri
- String uri = request.getRequestURI();
-
- // uri中包含background时才进行过滤
- if (uri.indexOf("background") != -1) {
- // 是否过滤
- boolean doFilter = true;
- for (String s : notFilter) {
- if (uri.indexOf(s) != -1) {
- // 如果uri中包含不过滤的uri，则不进行过滤
- doFilter = false;
- break;
- }
- }
- if (doFilter) {
- // 执行过滤
- // 从session中获取登录者实体
- Object obj = request.getSession().getAttribute("loginedUser");
- if (null == obj) {
- // 如果session中不存在登录者实体，则弹出框提示重新登录
- // 设置request和response的字符集，防止乱码
- request.setCharacterEncoding("UTF-8");
- response.setCharacterEncoding("UTF-8");
- PrintWriter out = response.getWriter();
- String loginPage = "....";
- StringBuilder builder = new StringBuilder();
- builder.append("<script type="text/javascript">");
- builder.append("alert('网页过期，请重新登录！');");
- builder.append("window.top.location.href='");
- builder.append(loginPage);
- builder.append("';");
- builder.append("</script>");
- out.print(builder.toString());
- } else {
- // 如果session中存在登录者实体，则继续
- filterChain.doFilter(request, response);
- }
- } else {
- // 如果不执行过滤，则继续
- filterChain.doFilter(request, response);
- }
- } else {
- // 如果uri中不包含background，则继续
- filterChain.doFilter(request, response);
- }
- }
-
- }
写完过滤器后，需要在web.xml中进行配置：
- <filter>
- <filter-name>sessionFilter</filter-name>
- <filter-class>com.test.spring.filter.SessionFilter</filter-class>
- </filter>
- <filter-mapping>
- <filter-name>sessionFilter</filter-name>
- <url-pattern>/*</url-pattern>
- </filter-mapping>
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持程序员之家。 | 
