How to solve the problem of Ajax request session failure

HTML Servlet Filter jQuery Generally speaking, our projects have login filters, which are enough for general requests. But AJAX is an exception, so the solution is to set the response to session invalidation.

Generally speaking, our projects have login filters, and general requests are enough. But AJAX is an exception, so the solution is to set the response to session invalidation.

It is divided into two parts: filter and page JS settings. Let’s look at the modification of the filter first:

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
 * 登录过滤器
 *　　拥有Session是否失效和用户是否登录2个条件判断
 *　　如果是ajax请求则设置session超时
 * @author Merlin.Ma
 *
 */
public class LoginFilter implements Filter{
  private String redirectUrl = "/login.html";
  private String sessionKey = "userName";
  @Override
  public void destroy() {
  }
  @Override
  public void doFilter(ServletRequest request, ServletResponse response,
      FilterChain chain) throws IOException, ServletException {
    HttpServletRequest req = (HttpServletRequest) request;
    HttpServletResponse rep = (HttpServletResponse) response;
    HttpSession session = req.getSession();
    if( session == null || session.getAttribute(sessionKey) == null){
      //如果判断是 AJAX 请求,直接设置为session超时
      if( req.getHeader("x-requested-with") != null && req.getHeader("x-requested-with").equals("XMLHttpRequest") ) {
        rep.setHeader("sessionstatus", "timeout"); 
      } else {
        rep.sendRedirect( req.getContextPath() + redirectUrl);
      }
    }else {
      chain.doFilter(request, response);
    }   
  }
  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
    String url = filterConfig.getInitParameter("redirectUrl");
    String key = filterConfig.getInitParameter("sessionKey");
    redirectUrl = url == null? redirectUrl:url;
    sessionKey = key == null ? sessionKey : key ;
  }
}

The code is simple, so there won’t be too many comments. Now let’s look at the JS part of the code. . Of course it is based on jQuery~~

//全局的ajax访问，处理ajax清求时sesion超时 
$.ajaxSetup({
  contentType : "application/x-www-form-urlencoded;charset=utf-8",
  complete : function(XMLHttpRequest, textStatus) {
    var sessionstatus = XMLHttpRequest.getResponseHeader("sessionstatus"); // 通过XMLHttpRequest取得响应头，sessionstatus，
    if (sessionstatus == "timeout") {
      // 如果超时就处理 ，指定要跳转的页面
      window.location.replace("login.html");
    }
  }
});

The page loads this js code and then starts calling ajax. If you are not logged in or the session is invalid, you can see the page jump to the login page.

The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.

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