SpringBoot Filter

1. Complete the registration of the Filter component by scanning the annotations

1. Create a class, implement the Filter interface, and implement the doFilter() method

2. Use annotation @WebFilter in this class , set filterName and urlPatterns

3. Write code in doFilter

4. Write startup class: add annotation @ServletComponentScan

   /**
    * SpringBoot Integration Filter Method One Project www.fhadmin.org
    */
   //@WebFilter(filterName="FirstFilter" , urlPatterns= {"*.do","*.jsp"})
   @WebFilter(filterName="FirstFilter" , urlPatterns= "/first")
   public class FirstFilter implements Filter {
   
   	@Override
   	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
   			throws IOException, ServletException {
   		System.out.println("进入Filter");
   		chain.doFilter(request, response);
   		System.out.println("Leave Filter");
   	}
   }

//项目 www.fhadmin.org
@SpringBootApplication
@ServletComponentScan
public class App {
	public static void main(String[] args) {
		SpringApplication.run(App.class, args);
	}
}

urlPatterns  is an array type, which can intercept multiple For example: urlPatterns= {" .do"," .jsp"}

2. Complete the Filter component registration through the method

1. Create a class, implement the Filter interface, and implement the doFilter() method

2. Write startup class

• Add a method, the return value must be an object of FilterRegistrationBean , he can create an instance of the Filter object

• Create a FilterRegistrationBean object and pass in the instantiated Filter object

• Add Url, bean.addUrlPatterns();

• Return FilterRegistrationBean object

• Add @Bean annotation to this method

	/**
	 * Register for the Filter project www.fhadmin.org
	 */ 
	@Bean
	public FilterRegistrationBean getFilterRegistrationBean() {
		FilterRegistrationBean bean  = new FilterRegistrationBean(new SecondFilter());
		//bean.addUrlPatterns(new String[] {"*.do","*.jsp"});
		bean.addUrlPatterns("/second");
		return bean;
	}