RESTful API的拦截
场景：对RESTfulAPI作统一的处理，比如希望对所有的RESTfulAPI记录服务处理的时间。
一、过滤器Filter
可以拿到原始的http请求和响应的信息，
但是拿不到真正处理请求的那个方法的信息。
自定义TimeFilter：
@Component
public class TimeFilter implements Filter{
@Override
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("time filter init");
}
@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耗时: "+(new Date().getTime()-start));
System.out.println("time filter finish");
}
@Override
public void destroy() {
System.out.println("time filter destroy");
}
}
控制台打印：
time filter init
time filter start
进入getInfo服务
time filter 耗时：0
time filter finish
在使用第三方过滤器时，需要通过web.xml配置；但对springboot来说，没有该配置文件
使用配置类：
@Configuration
public class WebConfig {
@Bean
public FilterRegistrationBean timeFiler() {
FilterRegistrationBean registrationBean = new FilterRegistrationBean();
TimeFilter timeFilter = new TimeFilter();
registrationBean.setFilter(timeFilter);
List<String> urls = new ArrayList<>();
urls.add("/*");//所有路径都起作用
registrationBean.setUrlPatterns(urls);
return registrationBean;
}
}
二、拦截器Interceptor
既可以拿到原始的http请求和响应，
也可以拿到真正处理请求的方法的信息，
但是拿不到具体方法被调用的时候的调用的参数的值。
使用Interceptor记录服务耗时
TimeInterceptor：
package com.hcx.web.interceptor;
import java.util.Date;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
@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));
}
//不管控制器方法成功还是失败，都会进入该方法
@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);
}
}
配置：
@Configuration
public class WebConfig extends WebMvcConfigurerAdapter{
@Autowired
private TimeInterceptor timeInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(timeInterceptor);
}
@Bean
public FilterRegistrationBean timeFiler() {
FilterRegistrationBean registrationBean = new FilterRegistrationBean();
TimeFilter timeFilter = new TimeFilter();
registrationBean.setFilter(timeFilter);
List<String> urls = new ArrayList<>();
urls.add("/*");
registrationBean.setUrlPatterns(urls);
return registrationBean;
}
}
运行结果：
time filter start
preHandle
com.hcx.web.controller.UserController$$EnhancerBySpringCGLIB$$ab2fe549
getInfo
进入getInfo服务
postHandle
time interceptor耗时：2
afterCompletion
time interceptor耗时：2
ex is null
time filter耗时: 4
time filter finish
如果方法抛出异常：
@GetMapping("/{id:\\d+}")
@JsonView(User.UserDetailView.class)
public User getInfo(@PathVariable String id) {
throw new UserNotExistException(id);
// System.out.println("进入getInfo服务");
// User user = new User();
// user.setUsername("tom");
// return user;
}
运行结果：没有了posthandler，ex在afterCompletion为空是因为异常处理器ControllerExceptionHandler把抛出去的异常处理了，没有传递到方法里。（即ControllerExceptionHandler该控制器是在afterCompletion之前执行的），除非抛出的异常没有被该异常处理器处理，比如runtimeException。
time filter init
time filter start
preHandle
com.hcx.web.controller.UserController$$EnhancerBySpringCGLIB$$68887b2a
getInfo
afterCompletion
time interceptor耗时：40
ex is null
time filter耗时: 49
time filter finish
局限：无法知道方法中的具体参数
三、切片Aspect
可以拿到方法被调用的时候传递进来的参数的值，
但是拿不到原始的http请求和响应的对象。
springaop.png
第一步：需要添加依赖：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
第二步：编写切面类
@Aspect
@Component
public class TimeAspect {
@Around("execution(* com.hcx.web.controller.UserController.*(..))")
public Object handleControllerMethod(ProceedingJoinPoint pjp) throws Throwable {
System.out.println("time aspect start");
//方法参数的数组
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 耗时："+(new Date().getTime() - start));
System.out.println("time aspect end");
return object;
}
}
控制台打印：
time filter start
preHandle
com.hcx.web.controller.UserController$$EnhancerBySpringCGLIB$$ab2fe549
getInfo
time aspect start
arg is 1
进入getInfo服务
time aspect 耗时：0
time aspect end
postHandle
time interceptor耗时：2
afterCompletion
time interceptor耗时：2
ex is null
time filter耗时: 4
time filter finish
拦截执行顺序.png
