Interceptor

Customize a normal interceptor

Here is the same as before to create a normal interceptor

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
                 System.out.println("My Interceptor");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}

Create a configuration class

Create a configuration class, add the relevant interceptor in the configuration class, here you can configure multiple interceptors, add @Configuration class on this class, this will be managed by the spring container.

/**
   * Interceptor configuration class
 */
 @Configuration// indicates that the class will be created by the spring container
public class InterceptorConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        InterceptorRegistration r1 = registry.addInterceptor(new PermissionInterceptor());
                 / / Add an intercept request
        r1.addPathPatterns("/*");
                 / / Add unblocked requests
        r1.excludePathPatterns("/login");

                 / / The above is the same as the following
        //registry.addInterceptor(new PermissionInterceptor()).addPathPatterns("/*").excludePathPatterns("/login");
    }
}

Then enter the appropriate url in the browser to test.

filter

method one:

Create a normal filter

@WebFilter(urlPatterns="/*")
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        System.out.println("Enter filter filter");
        chain.doFilter(request, response);
    }
    @Override
    public void destroy() {
    }
}

Add the annotation configuration filter to the entry method. @ServletComponentScan will scan the servlet-related annotations, such as @WebServlet, @WebFilter, @WebListener.

@SpringBootApplication
@ServletComponentScan(basePackages={"com.monkey1024.filter"})
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

Method Two:

Create a configuration class configuration filter, where @Bean is equivalent to the bean tag in the previous spring configuration file

@Configuration
public class FilterConfig {


    @Bean
    public FilterRegistrationBean myFilterRegistration() {
        FilterRegistrationBean registration = new FilterRegistrationBean(new MyFilter());
        registration.addUrlPatterns("/*");
        return registration;
    }
}

Configuring the servlet

method one:

Create a normal servlet

@WebServlet("/myServlet")
public class MyServlet extends HttpServlet {
    private static final long serialVersionUID = -4134217146900871026L;
    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().print("hello word");
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req, resp);
    }
}

Add annotations to the main class and configure the package where the servlet is located

@SpringBootApplication
@ServletComponentScan(basePackages="com.monkey1024.servlet")
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

Method 2:

@Configuration
public class ServletConfig {
    @Bean
    public ServletRegistrationBean myServletRegistrationBean(){
        ServletRegistrationBean registration = new ServletRegistrationBean(new MyServlet(), "/servlet/myServlet");
        return registration;
    }
}