spring中过滤器（filter）、拦截器（interceptor）和切面（aop）的执行顺序

1.程序执行的顺序是先进过滤器，再进拦截器，最后进切面。注意：如果拦截器中preHandle方法返回的为false时，则无法进入切面，例子如下

@RestController
@RequestMapping("/user")
public class UserController {

    @GetMapping("/{id:\\d+}")
	@JsonView(User.UserDetailView.class)
	public User getInfo(@PathVariable String id) {
		User user = new User();
		user.setUsername("tom");
		return user;
	}
}

编写方法的过滤器：

@Component
public class TimeFilter implements Filter {

	/* (non-Javadoc)
	 * @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
	 */
	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		System.out.println("time filter init");

	}

	/* (non-Javadoc)
	 * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
	 */
	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		System.out.println("time filter start");
		long start = new Date().getTime();
		chain.doFilter(request, response);
		System.out.println("time filter:"+ (new Date().getTime() - start));
		System.out.println("time filter finish");

	}

	/* (non-Javadoc)
	 * @see javax.servlet.Filter#destroy()
	 */
	@Override
	public void destroy() {
		System.out.println("time filter destroy");

	}

}

编写方法的拦截器：

@Component
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;
	}

	
	@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 耗时:"+ (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 耗时:"+ (new Date().getTime() - start));
		System.out.println("ex is "+ex);
	}

}

编写方法的切面：

@Aspect
@Component
public class TimeAspect {

	@Before("execution(public * com.hu.web.controller.UserController.*(..))")
	public Object handlerControllerMethod() throws Throwable {
		System.out.println("time aspect start");			
		return new Object();
	}
}

运行结果：1、当拦截器中preHandle的方法返回为true时：

time filter start
preHandle
com.hu.web.controller.UserController$$EnhancerBySpringCGLIB$$b0bb0dcf
getInfo
time aspect start
postHandle
time interceptor 耗时:76
afterCompletion
time interceptor 耗时:76
ex is null
time filter:92
time filter finish
time filter start
time filter:46
time filter finish

2、当拦截器中preHandle的方法返回为false时：

time filter start
preHandle
com.hu.web.controller.UserController$$EnhancerBySpringCGLIB$$b0bb0dcf
getInfo
time filter:12
time filter finish
time filter start
time filter:23
time filter finish

2.当程序有异常抛出时，回先进入切面，然后在进入自定义的ControllerAdvice中。

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