springboot中有三种拦截器可供选择：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，
[email protected]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 List<String> 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
[email protected]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 }
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原文地址：https://www.cnblogs.com/zuxiaoyuan/p/9702363.html
时间： 2024-11-05 17:24:43