使用切片攔截REST服務 Filter Interceptor Aspect

攔截的方法

1. 過濾器 Filter 初始化 銷毀 doFilter處理邏輯
2. 攔截器 Interceptor 調用之前 控制器 調用之後 最終調用
3. 切片 Aspect

過濾器

@Component
public class TimeFilter implements Filter {

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		System.out.println("time filter start"); //在執行 過濾
		long start = new Date().getTime();
		chain.doFilter(request, response); //放行到下一個過濾器，過濾器執行完，去執行action流程
		System.out.println("time filter 耗時:"+ (new Date().getTime() - start));//流程執行完畢，列印時間
		System.out.println("time filter finish"); //列印完成
	}

	@Override
	public void init(FilterConfig arg0) throws ServletException {
		System.out.println("time filter init"); //程式啟動，執行初始化
	}
		@Override
	public void destroy() {
		System.out.println("time filter destroy");
	}

}
           

不用Component 配置 bean

@Configuration //期初 不用繼承 ，繼承了可以添加攔截器
public class WebConfig extends WebMvcConfigurerAdapter {
	@SuppressWarnings("unused")
	@Autowired
	private TimeInterceptor timeInterceptor;
	
	@Override
	public void addInterceptors(InterceptorRegistry registry) {
//		registry.addInterceptor(timeInterceptor);
	}
	
//	@Bean
	public FilterRegistrationBean timeFilter() {
		FilterRegistrationBean registrationBean = new FilterRegistrationBean();
		TimeFilter timeFilter = new TimeFilter();
		registrationBean.setFilter(timeFilter);
		List<String> urls = new ArrayList<>();
		urls.add("/*"); //自定義URL
		registrationBean.setUrlPatterns(urls);
		return registrationBean;
	}
}
           

缺點：是有哪個Action來處理的，filter是不知道的。filter是j2EE，resultController注解是mvc的

解決用 Interceptor(Spring架構提供的)

Interceptor

@Component //需要繼承 HandlerInterceptor
public class TimeInterceptor implements HandlerInterceptor {
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {
		System.out.println("preHandle");
		
		System.out.println(((HandlerMethod)handler).getBean().getClass().getName());
		System.out.println(((HandlerMethod)handler).getMethod().getName());
		
		request.setAttribute("startTime", new Date().getTime());
		return true; //preHandle 必須傳回true 才能繼續
	}

	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			ModelAndView modelAndView) throws Exception {
		System.out.println("postHandle");
		Long start = (Long) request.getAttribute("startTime");
		System.out.println("time interceptor 耗時:"+ (new Date().getTime() - start));

	}
	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
			throws Exception {
		System.out.println("afterCompletion");
		Long start = (Long) request.getAttribute("startTime");
		System.out.println("time interceptor 耗時:"+ (new Date().getTime() - start));
		System.out.println("ex is "+ex);
//@ControllerAdvice 
public class ControllerExceptionHandler //控制器的異常處理器 在interceptor之前
//攔截器會攔截所有的控制器
	}

}

           

之後還需要添加到interceptor中 才能用

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {
	@SuppressWarnings("unused")
	@Autowired
	private TimeInterceptor timeInterceptor;
	@Override
	public void addInterceptors(InterceptorRegistry registry) {
//		registry.addInterceptor(timeInterceptor);
	}
           

攔截器可以拿到 請求 響應 以及處理方法的對象（action）

缺點 ，無法拿到 方法的參數 （源碼組model的代碼是在執行的下面）

解決 用切片 Aspect

切片 Aspect

//依賴
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-aop</artifactId>
		</dependency>
           

@Aspect
@Component
public class TimeAspect {
	@Around("execution(* com.imooc.web.controller.UserController.*(..))")
	public Object handleControllerMethod(ProceedingJoinPoint pjp) throws Throwable {
		System.out.println("time aspect start");
		Object[] args = pjp.getArgs();
		for (Object arg : args) {
			System.out.println("arg is "+arg);
		}
		long start = new Date().getTime();
		Object object = pjp.proceed();
		System.out.println("time aspect 耗時:"+ (new Date().getTime() - start));
		System.out.println("time aspect end");
		return object;
	}
}
           

切片拿不到原始的http請求和響應

攔截順序

出了異常，最先捕獲異常的是 Aspect ，之後有Advice 異常處理器 處理 ，如果繼續抛，繼續往上

不出 異常 沒有ControllerAdvice

@ControllerAdvice
public class ControllerExceptionHandler {
	@ExceptionHandler(UserNotExistException.class)
	@ResponseBody
	@ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
	public Map<String, Object> handleUserNotExistException(UserNotExistException ex) {
		Map<String, Object> result = new HashMap<>();
		result.put("id", ex.getId());
		result.put("message", ex.getMessage());
		return result;
	}
}