SSM拦截ajax请求判断session过期

「爱情、让人受尽委屈。」 2021-06-24 16:10 479阅读 0赞

项目使用ssm作为后台框架，需要在后台判断session是否过期，并跳转登录页。  
1.定义一个filter，拦截所有的请求。

package com.acat.filter;
    
    import javax.servlet.*;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    import java.io.IOException;
    import java.io.PrintWriter;
    
    /**
     * @Description：session过期拦截
     * @Author:yangfuren
     * @Date: Created in 13:31 2019-04-25
     * @Modified By:
     */
    public class SessionTimeOutFilter implements Filter{
    
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
            HttpServletRequest request = (HttpServletRequest) servletRequest;
            HttpServletResponse response = (HttpServletResponse) servletResponse;
            HttpSession session = request.getSession();
            //请求全路径
            String requestUri = request.getRequestURI();
            //项目名
            String contextPath = request.getContextPath();
            //不拦截的url及资源
            String[] urls = {"/login.html","/loginin",".js",".css",".ico",".jpg",".png"};
            boolean flag = true;
            for (String str : urls) {
                if (requestUri.indexOf(str) != -1) {
                    flag =false;
                    break;
                }
            }
            if (!flag) {
                filterChain.doFilter(servletRequest, servletResponse);
                return;
            }
    
            Integer classId = (Integer) session.getAttribute("fenzuId");
            //如果用户不存在
            if (classId == null) {
                //获取ajax参数值
                String ajaxHeader = request.getHeader("X-Requested-With");
                //如果是ajax请求
                if("XMLHttpRequest".equals(ajaxHeader)) {
                    response.setCharacterEncoding("utf-8");
                    response.setContentType("application/json; charset=utf-8");
                    PrintWriter out = response.getWriter();
                    //json数据
                    out.write("{\"status\":401,\"msg\":\"您的登录已过期\"}");
                    out.flush();
                    out.close();
                }else {
                    response.sendRedirect(contextPath+"/login.html");
                }
            }else {
                filterChain.doFilter(servletRequest,servletResponse);
            }
        }
    
        @Override
        public void destroy() {
    
        }
    }

2.在web.xml中配置filter

<filter>
            <filter-name>sessionFilter</filter-name>
            <filter-class>com.acat.filter.SessionTimeOutFilter</filter-class>
        </filter>
        <filter-mapping>
            <filter-name>sessionFilter</filter-name>
            <url-pattern>/*</url-pattern>
        </filter-mapping>
    
        
        <session-config>
            <session-timeout>180</session-timeout>
        </session-config>

3.在进行ajax返回时，根据状态码判断并跳转到login页面：

$.ajax({
                url: url+"/itemType/saveItemType",//后台接收的url
                type: 'POST',
                data: dataJson,
                dataType: 'JSON',
                contentType: 'application/json;charset=UTF-8',
                async: false,
                success: function (result) {
                    //登录过期，跳转到登录界面
                    if(result.status == 401) {
                        alert("登录过期,请重新登录!")
                        window.location.href=url+"/login.html";
                        return
                    }else {
                        alert("分类添加成功！");
                        location.reload();
                    }
                }
            });