spring boot 拦截器

1、创建ServletConfig配置类

package com.pn.config;

import com.pn.filter.LoginFilter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.core.ReactiveRedisTemplate;

@Configuration
public class ServletConfig {

    //0库 博主自己封装的分组redis，可以使用自己的redis
    @Autowired
    @Qualifier("reactiveRedisTemplateDb0")
    private ReactiveRedisTemplate<String, Object> redisTemplate;

    @Bean
    public FilterRegistrationBean filterRegistrationBean() {
        //创建ServletRegistrationBean的Bean对象
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        //创建自定义过滤器
        LoginFilter loginCheckFilter = new LoginFilter();
        //手动注入redis模板
        loginCheckFilter.setRedisTemplate(redisTemplate);
        //将自定义过滤器注册给到filterRegistrationBean
        filterRegistrationBean.setFilter(loginCheckFilter);
        // 定义拦截的请求
        filterRegistrationBean.addUrlPatterns("/*");//  "/*"所有请求
//        filterRegistrationBean.addInitParameter("paramName", "paramValue");// 可以添加参数addInitParameter("k","v")传值
        return filterRegistrationBean;
    }
}

---

2、LoginFilter自定义的过滤器

package com.pn.filter;

import com.alibaba.fastjson.JSON;
import com.pn.entity.Result;
import com.pn.utils.WarehouseConstants;
import org.springframework.data.redis.core.ReactiveRedisTemplate;
import org.springframework.util.StringUtils;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

public class LoginFilter implements Filter {

    //将redis模板定义为其成员变量
    private ReactiveRedisTemplate<String, Object> redisTemplate;

    //成员变量redis模板的set方法
    public void setRedisTemplate(ReactiveRedisTemplate<String, Object> redisTemplate) {
        this.redisTemplate = redisTemplate;
    }

    /**
     * 跨域设置
     * @param request
     * @param response
     */
    private void handleCors(HttpServletRequest request, HttpServletResponse response) {
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE");
        response.setHeader("Access-Control-Allow-Headers", "*");
        response.setHeader("Access-Control-Allow-Credentials", "true");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest)servletRequest;
        HttpServletResponse response = (HttpServletResponse)servletResponse;

        // 处理跨域请求
        handleCors(request, response);
        if ("OPTIONS".equalsIgnoreCase(request.getMethod())) {
            response.setStatus(HttpServletResponse.SC_OK);
            return;
        }

        //获取请求url接口
        String path = request.getServletPath();
        // 1、白名单直接放行,urlList.add() 放行的api
        List<String> urlList = new ArrayList<>();
        urlList.add("/captcha/captchaImage");
        urlList.add("/login");
        urlList.add("/logout");
        //对static下的/img/upload中的静态资源图片的访问直接放行
        if(urlList.contains(path)||path.contains("/img/upload")){
            //放行
            filterChain.doFilter(request, response);
            return;
        }
        /**
         * 其他请求带有token,判断redis存的token是否存在
         */
        // 2、拿到前端归还的token，request.getHeader("请求头token字段")
        String clientToken = request.getHeader(WarehouseConstants.HEADER_TOKEN_NAME);
        //校验token,校验通过请求放行
        if(StringUtils.hasText(clientToken)&& Boolean.TRUE.equals(redisTemplate.hasKey(clientToken).block())){
            //放行
            filterChain.doFilter(request, response);
            return;
        }

        /**
         * 其他请求token是否过期，或者没有token的
         * 校验失败,向前端响应失败的Result对象转成的json串
         */
        Result result = Result.err(Result.CODE_ERR_UNLOGINED, "请登录！");
        String jsonStr = JSON.toJSONString(result);
        response.setContentType("application/json;charset=UTF-8");
        PrintWriter out = response.getWriter();
        out.print(jsonStr);
        out.flush();
        out.close();
    }
}