说明
之前学了在springboot项目中过滤器、监听器、拦截器的使用，在这里记录总结下。
正文
对于过滤器和监听器，在springboot中可以使用两种配置方式：
第一种，采用Servlet3.0的注解进行配置 @WebFilter @WebListener，使用此方式要在启动类上使用@ServletComponentScan注解
第二种，使用配置bean的方式，springboot提供了FilterRegistrationBean和ServletListenerRegistrationBean
Filter
实现Filter接口创建自定义过滤器
第一种
@WebFilter(urlPatterns = "/hello",filterName = "demofilter")
public class DemoFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("Remote Host: " + servletRequest.getRemoteHost());
System.out.println("Remote Address: " + servletRequest.getLocalAddr());
filterChain.doFilter(servletRequest,servletResponse);
}
@Override
public void destroy() {
}
}
启动类添加@ServletComponentScan
@SpringBootApplication
@ServletComponentScan
public class FilterApplication {
public static void main(String[] args) {
SpringApplication.run(FilterApplication.class, args);
}
}
第二种
不需要在DemoFilter类上添加注解，在启动类中创建bean
@SpringBootApplication
public class FilterApplication {
public static void main(String[] args) {
SpringApplication.run(FilterApplication.class, args);
}
@Bean
public FilterRegistrationBean registrationBean(){
FilterRegistrationBean filterbean = new FilterRegistrationBean();
filterbean.setFilter(new DemoFilter());
filterbean.setName("demofilter");
filterbean.addUrlPatterns("/hello");
return filterbean;
}
}
Listener
实现ServletContextListener接口，创建项目启动监听类
第一种
@WebListener
public class DemoListener implements ServletContextListener {
@Override
public void contextInitialized(ServletContextEvent servletContextEvent) {
System.out.println("DemoListener Context Initialized");
}
@Override
public void contextDestroyed(ServletContextEvent servletContextEvent) {
System.out.println("DemoListener Context Destroyed");
}
}
注意@ServletComponentScan一定不能忘
@SpringBootApplication
@ServletComponentScan
public class ListenerApplication {
public static void main(String[] args) {
SpringApplication.run(ListenerApplication.class, args);
}
}
第二种
@SpringBootApplication
public class ListenerApplication {
public static void main(String[] args) {
SpringApplication.run(ListenerApplication.class, args);
}
@Bean
public ServletListenerRegistrationBean<ServletContextListener> listenerRegistrationBean(){
ServletListenerRegistrationBean listenerRegistrationBean= new ServletListenerRegistrationBean();
listenerRegistrationBean.setListener(new DemoListener());
return listenerRegistrationBean;
}
}
Interceptor
对于拦截器，需要使用WebMvcConfigurerAdapter进行注册，继承此类重写addInterceptors方法，将自定义的拦截器进行注册。
实现HandlerInterceptor接口创建自定义拦截器
@Component
public class DemoInterceptor implements HandlerInterceptor {
// This is used to perform operations before sending the request to the controller.
// This method should return true to return the response to the client
@Override
public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
System.out.println("Pre Handle method is Calling");
return true;
}
// This is used to perform operations before sending the response to the client
@Override
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
System.out.println("Post Handle method is Calling");
}
// This is used to perform operations after completing the request and response
@Override
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
System.out.println("Request and Response is completed");
}
}
@Component
public class DemoInterceptorConfig extends WebMvcConfigurerAdapter {
@Autowired
private DemoInterceptor demoInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(demoInterceptor).addPathPatterns("/hello");
}
}
源码地址：
https://github.com/Edenwds/springboot_study/tree/master/filter
https://github.com/Edenwds/springboot_study/tree/master/listener
https://github.com/Edenwds/springboot_study/tree/master/interceptor
参考资料：
https://www.tutorialspoint.com/spring_boot/index.htm
https://blog.csdn.net/liu455042806/article/details/79875999?utm_source=blogxgwz0
https://blog.csdn.net/king_is_everyone/article/details/53116744?utm_source=blogxgwz5
