杭州seo建站,制作公司网站设,怎么做网页快照,淘宝商城正品若要实现对请求的过滤#xff0c;有三种方式可供选择#xff1a;filter、interceptort和aop。本文主要讨论三种拦截器的使用场景与使用方式。 下文中的举例功能是计算每个请求的从开始到结束的时间#xff0c;例子来源是慕课网。 一、filter 特点#xff1a;可以获取原始的…若要实现对请求的过滤有三种方式可供选择filter、interceptort和aop。本文主要讨论三种拦截器的使用场景与使用方式。 下文中的举例功能是计算每个请求的从开始到结束的时间例子来源是慕课网。 一、filter 特点可以获取原始的ServletRequest但无法获取具体方法 实现 1.继承javax.servlet.Filter类 2.Component注解将其注入到框架中 3.实现其中的dofilter方法所有的请求都会经过该方法可以在此计算出每个请求的耗时代码如下 1 package com.zzy.web.filter;2 3 import java.io.IOException;4 import java.util.Date;5 6 import javax.servlet.Filter;7 import javax.servlet.FilterChain;8 import javax.servlet.FilterConfig;9 import javax.servlet.ServletException;
10 import javax.servlet.ServletRequest;
11 import javax.servlet.ServletResponse;
12
13 import org.springframework.stereotype.Component;
14
15 Component
16 public class TimeFilter implements Filter{
17
18 Override
19 public void init(FilterConfig filterConfig) throws ServletException {
20 // TODO Auto-generated method stub
21 System.out.println(filter init);
22
23 }
24
25 Override
26 public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
27 throws IOException, ServletException {
28 // TODO Auto-generated method stub
29 Long startTime new Date().getTime();
30 System.out.println(filter 请求开始时间: startTime);
31 chain.doFilter(request, response);
32 Long endTime new Date().getTime();
33 System.out.println(filter 请求结束时间 endTime ,请求耗时 (endTime - startTime));
34
35 }
36
37 Override
38 public void destroy() {
39 // TODO Auto-generated method stub
40
41 }
42
43 } 注如果有的框架没有Component 这个注解可以自己写一个配置类在该类中指定过滤器而且还可以指定过滤的url配置类如下 1 package com.zzy.web.config;2 3 import static org.assertj.core.api.Assertions.failBecauseExceptionWasNotThrown;4 5 import java.util.ArrayList;6 import java.util.List;7 8 import org.springframework.beans.factory.annotation.Autowired;9 import org.springframework.boot.web.servlet.FilterRegistrationBean;
10 import org.springframework.context.annotation.Bean;
11 import org.springframework.context.annotation.Configuration;
12 import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
13 import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
14
15 import com.zzy.web.filter.TimeFilter;
16 import com.zzy.web.interceptor.TimeInterceptor;
17
18 Configuration
19 public class WebConfig extends WebMvcConfigurerAdapter {
20
21 Autowired
22 private TimeInterceptor timeInterceptor;
23
24 // Override
25 // public void addInterceptors(InterceptorRegistry registry) {
26 // // TODO Auto-generated method stub
27 // registry.addInterceptor(timeInterceptor);
28 // }
29
30 Bean
31 public FilterRegistrationBean timeFilter() {
32 FilterRegistrationBean registrationBean new FilterRegistrationBean();
33 TimeFilter timeFilter new TimeFilter();
34 registrationBean.setFilter(timeFilter);
35 ListString urls new ArrayList();
36 urls.add(/user/*);
37 registrationBean.setUrlPatterns(urls);
38 return registrationBean;
39 }
40
41 } 二、interceptor 特点可以获取到原始的request和请求的方法但无法获取方法的具体参数的值。 实现 1.继承HandlerInterceptor接口 2.请求前的逻辑写在prehandle请求前调用 3.请求后的逻辑写在posthandle请求成功后调用失败则不调用 4.请求后不管成功失败都会调用aftercompletion。 5.intceptor方式继承了之后还没起作用还需要在配置类里面加一下把刚声明的拦截器注册一下。 代码示例 1 package com.zzy.web.interceptor;2 3 import java.util.Arrays;4 import java.util.Date;5 6 import javax.servlet.http.HttpServletRequest;7 import javax.servlet.http.HttpServletResponse;8 9 import org.springframework.stereotype.Component;
10 import org.springframework.web.method.HandlerMethod;
11 import org.springframework.web.servlet.HandlerInterceptor;
12 import org.springframework.web.servlet.ModelAndView;
13 Component
14 public class TimeInterceptor implements HandlerInterceptor {
15
16 Override
17 public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
18 throws Exception {
19 // TODO Auto-generated method stub
20 System.out.println(interceptor 执行preHandle);
21
22 request.setAttribute(startTime, new Date().getTime());
23 return true;
24 }
25
26 Override
27 public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
28 ModelAndView modelAndView) throws Exception {
29 // TODO Auto-generated method stub
30 Long startTime Long.parseLong(request.getAttribute(startTime).toString());
31 Long endTime new Date().getTime();
32 System.out.println(interceptor 执行postHandle);
33 System.out.println(interceptor 请求类((HandlerMethod)handler).getBean().getClass().getName());
34 System.out.println(interceptor 请求方法((HandlerMethod)handler).getMethod());
35 // System.out.println(interceptor 请求参数);
36 // Arrays.asList(((HandlerMethod)handler).getMethodParameters()).stream().forEach(arg-System.out.println(arg));
37 System.out.println(interceptor 请求耗时 (endTime - startTime));
38
39 }
40
41 Override
42 public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
43 throws Exception {
44 // TODO Auto-generated method stub
45 Long startTime Long.parseLong(request.getAttribute(startTime).toString());
46 Long endTime new Date().getTime();
47 System.out.println(interceptor 执行afterCompletion);
48 System.out.println(interceptor 请求类((HandlerMethod)handler).getBean().getClass().getName());
49 System.out.println(interceptor 请求方法((HandlerMethod)handler).getMethod());
50 System.out.println(interceptor 请求耗时 (endTime - startTime));
51 System.out.println(interceptor 请求异常 ex);
52
53 }
54
55 } 配置类如下 1 package com.zzy.web.config;2 3 import static org.assertj.core.api.Assertions.failBecauseExceptionWasNotThrown;4 5 import java.util.ArrayList;6 import java.util.List;7 8 import org.springframework.beans.factory.annotation.Autowired;9 import org.springframework.boot.web.servlet.FilterRegistrationBean;
10 import org.springframework.context.annotation.Bean;
11 import org.springframework.context.annotation.Configuration;
12 import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
13 import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
14
15 import com.zzy.web.filter.TimeFilter;
16 import com.zzy.web.interceptor.TimeInterceptor;
17
18 Configuration
19 public class WebConfig extends WebMvcConfigurerAdapter {
20
21 Autowired
22 private TimeInterceptor timeInterceptor;
23
24 Override
25 public void addInterceptors(InterceptorRegistry registry) {
26 // TODO Auto-generated method stub
27 registry.addInterceptor(timeInterceptor);
28 }
29
30
31 } 三、aop 特点能拿到方法和具体参数的值但是拿不到原始的servletrequest的信息。 实现 1.使用aspect注解 2.execution声明切面声明切面的语法可参考官网https://docs.spring.io/spring/docs/4.3.18.RELEASE/spring-framework-reference/htmlsingle/#aop-pointcuts 3.使用Around(方法前和方法后),Before方法前或After方法后 以下为Around举例代码如下 1 package com.zzy.web.aspect;2 3 import java.util.Date;4 5 import org.aspectj.lang.ProceedingJoinPoint;6 import org.aspectj.lang.annotation.Around;7 import org.aspectj.lang.annotation.Aspect;8 import org.codehaus.jackson.map.ObjectMapper;9 import org.springframework.stereotype.Component;
10
11 Aspect
12 Component
13 public class TimeAspect {
14
15 Around(execution(* com.zzy.web.controller.UserController.*(..)))
16 public Object test(ProceedingJoinPoint pjp) throws Throwable {
17 Long startTime new Date().getTime();
18 Object[] args pjp.getArgs();
19 for (Object arg : args) {
20 System.out.println(aspect 参数 arg);
21 }
22 Object object pjp.proceed();
23 System.out.println(aspect 请求耗时 (new Date().getTime() - startTime));
24 System.out.println(aspect 请求结果 new ObjectMapper().writeValueAsString(object));
25
26 return object;
27
28 }
29 } 下图是三种方式的拦截顺序图片来自慕课网 转载于:https://www.cnblogs.com/zuxiaoyuan/p/9702363.html
