SpringBoot1.5.12.RELEASE註冊Servlet三大元件【Servlet、Filter、Listener】

1.理由：由於SpringBoot預設是以jar包的方式啟動嵌入式的Servlet容器來啟動SpringBoot的web應用，沒有web.xml檔案。

2.註冊方式

import com.atguigu.springboot.filter.MyFilter;
import com.atguigu.springboot.listener.MyListener;
import com.atguigu.springboot.servlet.MyServlet;
import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.Arrays;

//該類放在主啟動類同目錄或其子目錄下，讓其自動掃描並加入IOC容器中

@Configuration
public class MyServerConfig {

    //ServletRegistrationBean------>註冊Servlet
    
    @Bean
    public ServletRegistrationBean myServlet(){
        ServletRegistrationBean registrationBean = new ServletRegistrationBean(new MyServlet(),"/myServlet");
        registrationBean.setLoadOnStartup(1);
        return registrationBean;
    }

   //FilterRegistrationBean------>註冊Filter

    @Bean
    public FilterRegistrationBean myFilter(){
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(new MyFilter());
        registrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet"));
        return registrationBean;
    }

   //ServletListenerRegistrationBean------>註冊Listener

    @Bean
    public ServletListenerRegistrationBean myListener(){
        ServletListenerRegistrationBean<MyListener> registrationBean = new ServletListenerRegistrationBean<>(new MyListener());
        return registrationBean;
    }

}

 

3.例子：SpringBoot幫我們自動SpringMVC的時候，自動的註冊SpringMVC的前端控制器；DIspatcherServlet；DispatcherServletAutoConfiguration中：

@Bean(name = DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)
@ConditionalOnBean(value = DispatcherServlet.class, name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
public ServletRegistrationBean dispatcherServletRegistration(
      DispatcherServlet dispatcherServlet) {
   ServletRegistrationBean registration = new ServletRegistrationBean(
         dispatcherServlet, this.serverProperties.getServletMapping());
    //預設攔截： /  所有請求；包靜態資源，但是不攔截jsp請求；   /*會攔截jsp
    //可以通過server.servletPath來修改SpringMVC前端控制器預設攔截的請求路徑
    
   registration.setName(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);
   registration.setLoadOnStartup(
         this.webMvcProperties.getServlet().getLoadOnStartup());
   if (this.multipartConfig != null) {
      registration.setMultipartConfig(this.multipartConfig);
   }
   return registration;
}