前言
项目中我们经常需要对RESTful api进行拦截，主流实现方法有filter、interceptor、aop，先说一下他们各自的实现。
Filter
AnimalFilter实现javax.servlet.Filter，项目启动时已初始化完成，可在控制台看到打印的初始化日志。
@Component
public class AnimalFilter implements Filter {
private Logger logger = LoggerFactory.getLogger(getClass());
@Override
public void init(FilterConfig filterConfig) throws ServletException {
logger.info("animalFilter 初始化。。。");
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
logger.info("animalFilter doFilter 。。。");
chain.doFilter(request,response);//过滤器将请求往下传递
}
@Override
public void destroy() {
logger.info("animalFilter 销毁。。。");
}
}
如何调用不被component修饰的filter，将上文中的component注解去除，通过下文方式，让注解生效并设置注解生效的url请求地址信息。
@Configuration
public class AnimalWebConfig {
@Bean
public FilterRegistrationBean animalFilter(){
FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
AnimalFilter animalFilter = new AnimalFilter();
filterRegistrationBean.setFilter(animalFilter);
List<String> urlPattern = new ArrayList<>();
urlPattern.add("/animal/getAnimalById/*");
filterRegistrationBean.setUrlPatterns(urlPattern);
return filterRegistrationBean;
}
}
由于filter获取的参数为ServletRequest request, ServletResponse response, FilterChain chain，无法知道是哪个类的那个方法调用，更无法知道调用时的参数。
Interceptor
首先编写一个AnimalInterceptor实现HandlerInteceptor方法，实现相应的三个方法，preHandle执行方法前执行返回的结果决定是否往下执行，postHandle当方法返回值时执行，afterCompletion无论成功或失败都将执行，前提是preHandler要返回true。
@Component
public class AnimalInterceptor implements HandlerInterceptor {
private Logger logger = LoggerFactory.getLogger(getClass());
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
HandlerMethod handlerMethod = (HandlerMethod) handler;
String methodName = handlerMethod.getMethod().getName();
logger.info("AnimalInterceptor:preHandle:methodName:" + methodName);
logger.info("AnimalInterceptor:preHandle");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
HandlerMethod handlerMethod = (HandlerMethod) handler;
logger.info("AnimalInterceptor:preHandle:methodName:" + handlerMethod.getMethod().getName());
logger.info("AnimalInterceptor:postHandle");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
logger.info("AnimalInterceptor:afterCompletion");
}
}
将写好的AnimalInterceptor注入到spring的interceptor注册中心即可
@Component
public class InterceptorConfig extends WebMvcConfigurerAdapter{
@Autowired
AnimalInterceptor animalInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(animalInterceptor);
}
}
虽然interceptor可以知道调用的controller，调用的方法，但获取不到调用方法的参数。
AOP
编写AnimalAspect如下，可将传递的参数打印出来，aop拦截规则设置请查看，https://blog.csdn.net/FU250/article/details/80219415
@Aspect
@Component
public class AnimalAspect {
private Logger logger = LoggerFactory.getLogger(getClass());
@Around("execution(* com.imooc.security.demo.web.controller..*.*(..))")
public Object handleAnimalController(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
Arrays.stream(proceedingJoinPoint.getArgs()).forEach(arg -> {
logger.info("arg:"+arg);
});
logger.info("AnimalAspect");
return proceedingJoinPoint.proceed();
}
}
三个拦截器的比较如下，根据自己的业务功能需求选择最合适的拦截器。
