spring boot 2.X拦截器的正确使用

第一步：创建拦截器

创建类实现HandlerInterceptor，类加上 @Component注解，重写HandlerInterceptor的三个方法，然后根据需要在三个方法中写业务逻辑即可

package com.nowcoder.community.controller.interceptor;

import...

@Component
public class LoginTicketInterceptor implements HandlerInterceptor {

    @Autowired
    private UserService userService;

    @Autowired
    private HostHolder hostHolder;


    @Override
    /**
     * 请求到Controller层之前
     */
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 从cookie中获取凭证
        String ticket = CookieUtil.getValue(request, "ticket");
        if (ticket != null) {
            // 查询凭证
            LoginTicket loginTicket = userService.findLoginTicket(ticket);
            // 检查凭证是否有效
            if (loginTicket != null && loginTicket.getStatus() == 0 && loginTicket.getExpired().after(new Date())) {
                // 根据凭证查询用户
                User user = userService.findUserById(loginTicket.getUserId());
                // 在本次请求中持有用户
                hostHolder.setUser(user);
                //构建用户认证结果存入SecurityContext,便于授权功能
                // 构建用户认证的结果,并存入SecurityContext,以便于Security进行授权.
                Authentication authentication = new UsernamePasswordAuthenticationToken(
                        user, user.getPassword(), userService.getAuthorities(user.getId()));
                SecurityContextHolder.setContext(new SecurityContextImpl(authentication));
            }
        }

        //释放请求
        return true;
    }

    @Override
    /**
     *Controller层响应到客户端之前
     */
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        User user = hostHolder.getUser();
        if (user != null && modelAndView != null) {
            modelAndView.addObject("loginUser", user);
        }
    }

    @Override
    /**
     * 响应结束之后
     */
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        hostHolder.clear();
        SecurityContextHolder.clearContext();
    }
}

第二步：创建拦截器配置类

创建一个类实现WebMvcConfigurer，在类上加上 @Configuration注解，并实现addInterceptors方法，将之前写的拦截器类注册到此配置类即可

package com.nowcoder.community.config;

import...

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

    /**
     * 注入自己编写的拦截器
     */
    @Autowired
    private AlphaInterceptor alphaInterceptor;
	@Autowired
    private LoginTicketInterceptor loginTicketInterceptor;
	@Autowired
    private MessageInterceptor messageInterceptor;
	@Autowired
    private DataInterceptor dataInterceptor;

	@Override
    /**
     *将拦截器进行注册配置
     */
    public void addInterceptors(InterceptorRegistry registry) {
        //添加拦截器
        registry.addInterceptor(alphaInterceptor)
                //静态资源不拦截
                .excludePathPatterns("/**/*.css", "/**/*.js", "/**/*.png", "/**/*.jpg", "/**/*.jpeg")
                //配置拦截路径
                .addPathPatterns("/register", "/login");

        registry.addInterceptor(loginTicketInterceptor)
                .excludePathPatterns("/**/*.css", "/**/*.js", "/**/*.png", "/**/*.jpg", "/**/*.jpeg");

        registry.addInterceptor(messageInterceptor)
                .excludePathPatterns("/**/*.css", "/**/*.js", "/**/*.png", "/**/*.jpg", "/**/*.jpeg");

        registry.addInterceptor(dataInterceptor)
                .excludePathPatterns("/**/*.css", "/**/*.js", "/**/*.png", "/**/*.jpg", "/**/*.jpeg");
    }

}

到此，拦截器配置成功