想要创建一个过滤器以检查Cookie，然后保存控制器中的对象和引用

想要创建一个过滤器以检查Cookie，然后保存控制器中的对象和引用

要创建过滤器，只需创建一个实现javax.servlet.Filter的类，就您而言，可能是这样

public class cookieFilter implements Filter {    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {        HttpServletRequest request = (HttpServletRequest) req;     cookie[] cookies = request.getcookies();        if (cookies != null){          for (cookie ck : cookies) { if ("nameOfMycookie".equals(ck.getName())) {     // read the cookie etc, etc     // ....     // set an object in the current request     request.setAttribute("myCoolObject", myObject) }        }        chain.doFilter(request, res);    }    public void init(FilterConfig config) throws ServletException {        // some initialization pre called when the filter is loaded    }    public void destroy() {        // executed when the filter is unloaded    }}

然后在您的web.xml中声明过滤器

<filter>    <filter-name>cookieFilter</filter-name>    <filter-class>        my.package.cookieFilter    </filter-class></filter><filter-mapping>    <filter-name>cookieFilter</filter-name>    <url-pattern>/*</url-pattern></filter-mapping>

此时，在您的控制器中，只需使用request.getAttribute（“ myCoolObject”）检查该请求中是否存在该外观即可