解決過濾器中設置cookie無效的問題

解決過濾器中設置cookie無效的問題

代碼現場

filterChain.doFilter(sessionSyncRequestWrapper, response);
Cookie emailCook = WebServletUtil.getSelectedCookie(request.getCookies(), Constant2.COOKIE_KEY_JSESSIONID, null);
        if (emailCook != null) {
            System.out.println("保存 :" + request.getSession().getId());
            emailCook.setMaxAge(12 * 60 * 60);
            emailCook.setPath("/");//設置cookie時,設置path爲根路徑
            response.addCookie(emailCook);
        } else {
            WebServletUtil.setSessionIdCookie( request.getSession().getId(),response,48);
        }

目的:設置cookie(JSESSIONID)的超時時間,讓cookie(JSESSIONID)持久化,
瀏覽器關閉以後,cookie(JSESSIONID)依然有效
可是實際沒有持久化,很奇怪
明明設置了很長的過時時間,爲何沒有生效呢?
測試了百遍,終於發現了問題

不生效的緣由

是由於 response 已經 commit了, 咱們看看response.isCommitted() 方法的解釋說明:

/**
     * Returns a boolean indicating if the response has been
     * committed.  A committed response has already had its status 
     * code and headers written.
     *
     * @return		a boolean indicating if the response has been
     *  		committed
     *
     * @see 		#setBufferSize
     * @see 		#getBufferSize
     * @see 		#flushBuffer
     * @see 		#reset
     *
     */

    public boolean isCommitted();

說白了,response若是已經commit了,再設置cookie(即response的header)不會生效.
由於我是在 filterChain.doFilter 以後設置cookie,因此一直沒有生效

解決方法:

在 filterChain.doFilter 以前設置cookie:

Cookie emailCook = WebServletUtil.getSelectedCookie(request.getCookies(), Constant2.COOKIE_KEY_JSESSIONID, null);
        if (emailCook != null) {
            System.out.println("保存 :" + request.getSession().getId());
            emailCook.setMaxAge(12 * 60 * 60);
            emailCook.setPath("/");//設置cookie時,設置path爲根路徑
            response.addCookie(emailCook);
        } else {
            WebServletUtil.setSessionIdCookie( request.getSession().getId(),response,48);
        }
        filterChain.doFilter(sessionSyncRequestWrapper, response);

注意:

1. 如何查看response 是否已經commit? 使用 response.isCommitted() ;
2. chain.doFilter(request, response); 以後response的狀態是已經commit

參考:
自定義實現session持久化