SpringBoot+shiro解决前后端分离session过期问题

1、自定义访问控制拦截器：AccessControlFilter，集成这个接口后要实现下面这三个方法。

abstract boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) throws Exception;  

boolean onAccessDenied(ServletRequest request, ServletResponse response, Object mappedValue) throws Exception; 

abstract boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception;  

2、在ShiroConfig加以下代码

  @Bean("shiroFilter")
    public ShiroFilterFactoryBean shiroFilter(SecurityManager securityManager) {
        ShiroFilterFactoryBean shiroFilter = new ShiroFilterFactoryBean();
        shiroFilter.setSecurityManager(securityManager);
        shiroFilter.setLoginUrl("/toLogin");
        shiroFilter.setUnauthorizedUrl("/");

        Map filterMap = new LinkedHashMap<>();
        filterMap.put("/login/**", "anon"); //登陆
        filterMap.put("/kaptcha", "anon");  //验证码
        filterMap.put("/global/*", "anon");  //全局路径（错误或者超时）

        filterMap.put("/favicon.ico", "anon");
        filterMap.put("/**", "authc");
        shiroFilter.setFilterChainDefinitionMap(filterMap);
        return shiroFilter;
    }

3、自定义GunsUserFilter

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.gizhi.guns.core.intercept;
import com.gizhi.guns.core.enumeration.RetEnum;
import com.gizhi.guns.core.util.R;
import com.gizhi.guns.core.util.RenderUtil;
import org.apache.shiro.subject.Subject;
import org.apache.shiro.web.filter.AccessControlFilter;
import org.apache.shiro.web.util.WebUtils;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

/**
 * Filter that allows access to resources if the accessor is a known user, which is defined as
 * having a known principal.  This means that any user who is authenticated or remembered via a
 * 'remember me' feature will be allowed access from this filter.
 * 

 * If the accessor is not a known user, then they will be redirected to the {@link #setLoginUrl(String) loginUrl}
 *
 * @since 0.9
 */
public class GunsUserFilter extends AccessControlFilter {

    /**
     *
     * 表示是否允许访问；mappedValue就是[urls]配置中拦截器参数部分，如果允许访问返回true，否则false；
     * (感觉这里应该是对白名单（不需要登录的接口）放行的)
     * 如果isAccessAllowed返回true则onAccessDenied方法不会继续执行
     * 这里可以用来判断一些不被通过的链接（个人备注）
     * * 表示是否允许访问 ，如果允许访问返回true，否则false；
     * @param request
     * @param response
     * @param mappedValue 表示写在拦截器中括号里面的字符串 mappedValue 就是 [urls] 配置中拦截器参数部分
     * @return
     * @throws Exception
     * */

    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {


        if (isLoginRequest(request, response)) {
            return true;
        } else {
            Subject subject = getSubject(request, response);
            // If principal is not null, then the user is known and should be allowed access.
            return subject.getPrincipal() != null;
        }
    }

    /**
     * 表示当访问拒绝时是否已经处理了；如果返回true表示需要继续处理；如果返回false表示该拦截器实例已经处理了，将直接返回即可。
     * onAccessDenied是否执行取决于isAccessAllowed的值，如果返回true则onAccessDenied不会执行；如果返回false，执行onAccessDenied
     * 如果onAccessDenied也返回false，则直接返回，不会进入请求的方法（只有isAccessAllowed和onAccessDenied的情况下）
     * */
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletResponse httpServletResponse = WebUtils.toHttp(response);

        //前端http请求中code为403的时候跳转到登陆页，R.fail()为你返回给前端的json对象
        RenderUtil.renderJson(httpServletResponse, R.fail(RetEnum.LOGIN_EXPIRED.getRet(),RetEnum.LOGIN_EXPIRED.getMsg()));

        return false;

    }
}

4、RenderUtil.java

package com.gizhi.guns.core.util;

import com.alibaba.fastjson.JSON;
import com.gizhi.guns.core.exception.GunsException;
import com.gizhi.guns.core.exception.GunsExceptionEnum;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

public class RenderUtil {

    /**
     * 渲染json对象
     */
    public static void renderJson(HttpServletResponse response, Object jsonObject) {
        try {
            response.setContentType("application/json");
            response.setCharacterEncoding("UTF-8");
            PrintWriter writer = response.getWriter();
            writer.write(JSON.toJSONString(jsonObject));
        } catch (IOException e) {
            throw new GunsException(GunsExceptionEnum.WRITE_ERROR);
        }
    }
}