解决Spring Boot 拦截器注入service为空的问题

问题：在自定义拦截器中，使用了@Autowaire注解注入了封装JPA方法的Service，结果发现无法注入，注入的service为空

0.原因分析

拦截器加载的时间点在springcontext之前，所以在拦截器中注入自然为null

1.需要在拦截器上加@Component

package com.fdzang.mblog.interceptor;

import com.fdzang.mblog.pojo.*;
import com.fdzang.mblog.service.*;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.List;
import java.util.Optional;

@Component
public class InitInterceptor implements HandlerInterceptor {
    @Autowired
    OptionsService optionsService;

    @Autowired
    UserService userService;

    @Autowired
    PageService pageService;

    @Autowired
    LabelService labelService;

    @Autowired
    ArticleService articleService;

    @Autowired
    CategoryService categoryService;

    @Autowired
    TagService tagService;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
        // TODO Auto-generated method stub
        //controller方法调用之前
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object o, ModelAndView mv)
            throws Exception {
        // TODO Auto-generated method stub
        //请求处理之后进行调用，但是在视图被渲染之前，即Controller方法调用之后
        HttpServletRequest req = (HttpServletRequest) request;
        HttpSession session=req.getSession();
        String isInited=(String)req.getSession().getAttribute("isInited");
        Optional<String> isInited_op=Optional.ofNullable(isInited);
        if(!isInited_op.isPresent()) {
            List<Options> options = optionsService.findAll();
            List<Page> pageNavigations = pageService.findAll();
            List<Label> labels = labelService.findAll();
            List<Category> mostUsedCategories = categoryService.getMostUsedCategories();
            List<Tag> mostUsedTags = tagService.getMostUsedTags();
            List<Article> mostCommentArticles = articleService.getMostCommentArticles();
            List<Article> mostViewCountArticles = articleService.getMostViewCountArticles();

            User adminUser = null;
            int paginationPageCount = 0;
            session.setAttribute("pageNavigations", pageNavigations);
            for (Options option : options) {
                session.setAttribute(option.getoId(), option.getOptionValue());
                if (option.getoId().equals("adminEmail")) {
                    adminUser = userService.getUserByEmail(option.getOptionValue());
                    session.setAttribute("adminUser", adminUser);
                    System.out.println(adminUser.getUserName());
                }
            }
            for (Label label : labels) {
                session.setAttribute(label.getoId(), label.getZh_cn());
            }
            session.setAttribute("servePath", "localhost:8080");
            session.setAttribute("isLoggedIn", false);
            session.setAttribute("loginURL", "/login");
            session.setAttribute("mostUsedCategories", mostUsedCategories);
            session.setAttribute("mostUsedTags", mostUsedTags);
            session.setAttribute("paginationPageCount", paginationPageCount);
            session.setAttribute("mostCommentArticles", mostCommentArticles);
            session.setAttribute("mostViewCountArticles", mostViewCountArticles);

            session.setAttribute("isInited", "inited");
        }
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object o, Exception e)
            throws Exception {
        //在整个请求结束之后被调用，也就是在DispatcherServlet
        //渲染了对应的视图之后执行，主要是用于进行资源清理工作
    }
}

2.进行拦截器配置

package com.fdzang.mblog.config;

import com.fdzang.mblog.interceptor.InitInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class InterceptorConfig extends WebMvcConfigurerAdapter {
    @Bean
    public InitInterceptor myInterceptor(){
        return new InitInterceptor();
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //多个拦截器组成一个拦截器链
        // addPathPatterns用于添加拦截规则
        // excludePathPatterns用户排除拦截
        //对来自/** 全路径请求进行拦截
        registry.addInterceptor(myInterceptor()).addPathPatterns("/**");
        super.addInterceptors(registry);
    }
}

参考博客：https://blog.csdn.net/wmh13262227870/article/details/77005920