05 SpringBoot注册Web组件

目录

一、SpringBoot注册web组件_注册Servlet

 注册方式一：全注解方式@WebServlet

 注册方式二：配置类注册Servlet

二、SpringBoot注册web组件_注册Filter

  注册方式一：全注解方式@WebFilter

 注册方式二：配置类注册Filter

三、SpringBoot注册web组件_注册Listener

注册方式一：全注解方式@WebListener

注册方式二：配置类注册Listener

四、知识点整理：

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一、SpringBoot注册web组件_注册Servlet

 注册方式一：全注解方式@WebServlet

1.编写Firstservlet

@WebServlet("/first")
public class FirstServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("first Servlet......");
    }
}

2.启动类添加@ServletComponentScan注解扫描web组件

@SpringBootApplication
//SpringBoot启动时扫描注册注解标注的Web组件
@ServletComponentScan
public class Springbootdemo2Application {
    public static void main(String[] args) {
        SpringApplication.run(Springbootdemo2Application.class, args);
        
    }
}

@ServletComponentScan可以扫描Servlet、Filter、Listen三个组件

3.运行结果：后台打印出“first Servlet.....” 

 注册方式二：配置类注册Servlet

1.编写SecondServlet

public class SecondServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("Second Servlet......");
    }
}

2.编写配置类ServletConfig注册Servlet

@SpringBootConfiguration
public class ServletConfig {
    //ServletRegistrationBean可以注册Servlet组件，将其放入Spring容器即可注册Servlet组件
    @Bean
    public ServletRegistrationBean getServletRegistrationBean(){
        //注册Servlet组件
        ServletRegistrationBean bean = new ServletRegistrationBean(new SecondServlet());
        //添加Servlet访问路径
        bean.addUrlMappings("/second");
        return bean;
    }
}

3.运行结果：后台打印出“Second Servlet.....” 

 

二、SpringBoot注册web组件_注册Filter

  注册方式一：全注解方式@WebFilter

1.编写FirstFilter

@WebFilter(urlPatterns = "/first")
public class FirstFilter 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("进入first Filter");
        filterChain.doFilter(servletRequest,servletResponse);
        System.out.println("离开first Filter");
    }
 
    @Override
    public void destroy() {
 
    }
}

2.启动类中的@ServletComponentScan注解扫描web组件

@SpringBootApplication
//SpringBoot启动时扫描注册注解标注的Web组件
@ServletComponentScan
public class Springbootdemo2Application {
    public static void main(String[] args) {
        SpringApplication.run(Springbootdemo2Application.class, args);
        
    }
}

3.运行结果：访问localhost：8080/first 

 注册方式二：配置类注册Filter

1.编写SecondFilter

public class SecondFilter 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("进入Second Filter");
        filterChain.doFilter(servletRequest,servletResponse);
        System.out.println("离开Second Filter");
    }
 
    @Override
    public void destroy() {
 
    }
}

2.编写配置类FilterConfig注册Filter

@SpringBootConfiguration
public class FilterConfig {
    //ServletRegistrationBean可以注册Servlet组件，将其放入Spring容器即可注册Servlet组件
    @Bean
    public FilterRegistrationBean getFilterRegistrationBean(){
        //注册Filter组件
        FilterRegistrationBean bean = new FilterRegistrationBean(new SecondFilter());
        //添加Filter过滤路径
        bean.addUrlPatterns("/second");
        return bean;
    }
}

3.运行结果：访问localhost：8080/second

 

三、SpringBoot注册web组件_注册Listener

注册方式一：全注解方式@WebListener

 1.编写FirstListener

@WebListener
public class FirstListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("First Listener Init....");
    }
 
    @Override
    public void contextDestroyed(ServletContextEvent sce) {
 
    }
}

2.运行结果：

注册方式二：配置类注册Listener

 1.编写SecondListener

public class SecondListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("Second Listener Init....");
    }
 
    @Override
    public void contextDestroyed(ServletContextEvent sce) {
 
    }
}

2.编写配置类ListenerConfig注册Listener

@Configuration
public class ListenerConfig {
    @Bean
    public ServletListenerRegistrationBean getServletListenerRegistrationBean(){
        ServletListenerRegistrationBean bean = new ServletListenerRegistrationBean(new SecondListener());
        return bean;
    }
}

3.运行结果：

 

四、知识点整理：