public class LoginStatus {
    public static User getStatus(HttpServletRequest request) {
        HttpSession session = request.getSession(false);
        if (session == null) {
            //當(dāng)前用戶未登錄
            return null;
        }
        User user = (User) session.getAttribute("user");
        if (user == null) {
            //當(dāng)前用戶未登錄
            return null;
        }
        return user;
    }
}

@Aspect // 說明該類為一個(gè)切面
@Component
public class UserAspect {
    // 定義切點(diǎn),使用 AspectJ表達(dá)式語法,攔截UserController所有方法
    @Pointcut("execution(* com.example.demo.controller.UserController.*(..))")
    public void pointcut(){}
    // 前置通知
    @Before("pointcut()")
    public void doBefore() {
        System.out.println("執(zhí)行Before前置通知");
    }
    // 添加環(huán)繞通知
    @Around("pointcut()")
    public Object doAround(ProceedingJoinPoint joinPoint) {
        Object result = null;
        System.out.println("執(zhí)行環(huán)繞通知的前置方法");
        try {
            // 執(zhí)行(攔截的)業(yè)務(wù)方法
            result = joinPoint.proceed();
        } catch (Throwable throwable) {
            throwable.printStackTrace();
        }
        System.out.println("執(zhí)行環(huán)繞通知的后置方法");
        return result;
    }
}

/**
 * 定義自定義攔截器實(shí)現(xiàn)用戶登錄校驗(yàn)
 */
@Configuration
public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        HttpSession session = request.getSession(false);
        if (session != null &&  session.getAttribute("userInfo") != null) {
            response.setStatus(200);
            return true;
        }
        response.setStatus(403);
        return false;
    }
}

@Configuration
public class AppConfig implements WebMvcConfigurer {
    //添加攔截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LoginInterceptor()) // 添加自定義攔截器
                .addPathPatterns("/**") //攔截所有接口
                .excludePathPatterns("/**/login")//排除的接口
    }
}

@Configuration
public class AppConfig implements WebMvcConfigurer {
    //添加攔截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LoginInterceptor()) // 添加自定義攔截器
                .addPathPatterns("/**")
                .excludePathPatterns("/**/*.html")//排除所有靜態(tài)資源
                .excludePathPatterns("/**/*.css")
                .excludePathPatterns("/**/*.js")
                .excludePathPatterns("/**/img/*");
    }
}

protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
        HttpServletRequest processedRequest = request;
        HandlerExecutionChain mappedHandler = null;
        boolean multipartRequestParsed = false;
        WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);
       //此處省略上面代碼
    // 調(diào)用預(yù)處理
    if (!mappedHandler.applyPreHandle(processedRequest, response)) {
        return;
    }
    // 執(zhí)行Controller中的業(yè)務(wù)
    mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
    if (asyncManager.isConcurrentHandlingStarted()) {
        return;
    }
    // ......后面代碼省略
}

boolean applyPreHandle(HttpServletRequest request, HttpServletResponse response) throws Exception {
        for(int i = 0; i < this.interceptorList.size(); this.interceptorIndex = i++) {
            // 獲取項(xiàng)?中使?的攔截器 HandlerIntercepto
            HandlerInterceptor interceptor = (HandlerInterceptor)this.interceptorList.get(i);
            if (!interceptor.preHandle(request, response, this.handler)) {
                this.triggerAfterCompletion(request, response, (Exception)null);
                return false;
            }
        }
        return true;
    }

@Configuration
public class AppConfig implements WebMvcConfigurer {
    @Override
    public void configurePathMatch(PathMatchConfigurer configurer) {
        configurer.addPathPrefix("blog",pre->true);
    }
}

@ControllerAdvice
public class ErrorAdvice  {
    @ExceptionHandler(Exception.class)
    @ResponseBody
    public Object handler(Exception e) {
        Map<String,Object> map = new HashMap<>();
        map.put("success",1);
        map.put("status",-1);
        map.put("message","服務(wù)器接口異常");
        return map;
    }
}

@ControllerAdvice
public class ErrorAdvice  {
    @ExceptionHandler(Exception.class)
    @ResponseBody
    public Object exceptionAdvice(Exception e) {
        Map<String,Object> map = new HashMap<>();
        map.put("success",1);
        map.put("status",-1);
        map.put("message","服務(wù)器接口異常");
        return map;
    }
    @ExceptionHandler(NullPointerException.class)
    @ResponseBody
    public Object nullPointerExceptionAdvice(NullPointerException exception) {
        Map<String,Object> map = new HashMap<>();
        map.put("success",1);
        map.put("status",-1);
        map.put("message",exception.toString());
        return map;
    }
}

@ControllerAdvice
public class ResponseAdvice implements ResponseBodyAdvice {
    /**
     * 內(nèi)容是否需要重寫，此方法可以選擇部分控制器和方法進(jìn)行重寫
     * 返回 true表示重寫
     */
    @Override
    public boolean supports(MethodParameter returnType, Class converterType) {
        return true;
    }
    /**
     *控制器方法返回之前會(huì)調(diào)用此方法
     */
    @Override
    public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType,
                                  Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
        Map<String,Object> result = new HashMap<>();
        result.put("success",200);
        result.put("status",1);
        result.put("data",body);
        return result;
    }
}