Shiro未登录时请求跳转问题

问题：未登录时浏览器发送的请求都会重定向，导致前端无法捕捉重定向后的消息。

原因：FormAuthenticationFilter.onAccessDenied()中做的重定向

解决：继承FormAuthenticationFilter，重写onAccessDenied方法,在config中配置filter

import com.alibaba.fastjson.JSONObject;
import org.apache.shiro.web.filter.authc.FormAuthenticationFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;


public class ShiroFormAuthenticationFilter extends FormAuthenticationFilter {
    private static final Logger log = LoggerFactory.getLogger(ShiroFormAuthenticationFilter.class);

    @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        if (this.isLoginRequest(request, response)) {
            if (this.isLoginSubmission(request, response)) {
                if (log.isTraceEnabled()) {
                    log.trace("Login submission detected.  Attempting to execute login.");
                }

                return this.executeLogin(request, response);
            } else {
                if (log.isTraceEnabled()) {
                    log.trace("Login page view.");
                }

                return true;
            }
        } else {
            HttpServletRequest req = (HttpServletRequest)request;
            HttpServletResponse resp = (HttpServletResponse)response;
            if (req.getMethod().equals(RequestMethod.OPTIONS.name())) {
                resp.setStatus(HttpStatus.OK.value());
                return true;
            } else {
                if (log.isTraceEnabled()) {
                    log.trace("Attempting to access a path which requires authentication.  Forwarding to the Authentication url [{}]" ,this.getLoginUrl());
                }
                
                resp.setHeader("Access-Control-Allow-Origin", req.getHeader("Origin"));
                resp.setHeader("Access-Control-Allow-Credentials", "true");
                resp.setContentType("application/json; charset=utf-8");
                resp.setCharacterEncoding("UTF-8");
                PrintWriter out = resp.getWriter();
                JSonObject result = new JSonObject();
                result.put("code",403);
                result.put("msg","未登录");
                out.println(result);
                out.flush();
                out.close();
                return false;
            }
        }
    }

}

@Configuration
public class ShiroConfig { 

    @Bean
    public ShiroFilterFactoryBean shiroFilterFactory(SecurityManager securityManager) {
        ShiroFilterFactoryBean shiroFilterFactoryBean = new ShiroFilterFactoryBean();
        shiroFilterFactoryBean.setSecurityManager(securityManager);
        Map filterChainDefinitionMap = new linkedHashMap<>();
        // 注意过滤器配置顺序不能颠倒
        // 配置过滤:不会被拦截的链接
        filterChainDefinitionMap.put("/login/**", "anon");
        filterChainDefinitionMap.put("/**", "authc");
        // 配置shiro默认登录界面地址，前后端分离中登录界面跳转应由前端路由控制，后台仅返回json数据
//        shiroFilterFactoryBean.setLoginUrl("/login/unauth");
        linkedHashMap filtsMap = new linkedHashMap<>();
        // 这里使用自定义的filter
        filtsMap.put("authc", new ShiroFormAuthenticationFilter());
        shiroFilterFactoryBean.setFilters(filtsMap);
        shiroFilterFactoryBean.setFilterChainDefinitionMap(filterChainDefinitionMap);
        return shiroFilterFactoryBean;
    }
}