SpringBoot的Web开发入门案例5—注册Servlets, Filter, Listener

SpringBoot的Web开发入门案例5—注册Servlets, Filter, Listener

注册Servlet

1. 创建MyServlet类

package com.blu.conf;

import java.io.IOException;

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

public class MyServlet extends HttpServlet{
	
	@Override
	public void init() throws ServletException {
		super.init();
		System.out.println("Servlet --- init()");
	}
	
	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//		super.service(req, resp);
		System.out.println("Servlet --- service()");
		resp.sendRedirect("/toLogin");
	}
}

2. 在配置类中添加Bean

	/**
	 *  <servlet>
	 * 		<servlet-name>
	 * 		<servlet-class>
	 *  </servlet>
	 *  <servlet-mapping>
	 *  	<servlet-name>
	 *  	<url-pattern>
	 *  </servlet-mapping>
	 */
	
	@Bean
	public ServletRegistrationBean<MyServlet> myServlet(){
		ServletRegistrationBean<MyServlet> ms = new ServletRegistrationBean<MyServlet>(new MyServlet(),"/ms");
		return ms;
	}

3. 启动项目，第一次访问路径http://localhost:60001/ms，控制台打印：

Servlet --- init()
Servlet --- service()

---

注册过滤器Filter

1. 创建MyFilter类

package com.blu.conf;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

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("执行了过滤器");
		chain.doFilter(request, response);
	}

	@Override
	public void destroy() {
	
	}
}

2. 在配置类中添加Bean

	/**
	 * <filtername>
	 * <urlpattern>
	 * 
	 */
	
	@Bean
	public FilterRegistrationBean<MyFilter> myFilter(){
		FilterRegistrationBean<MyFilter> filter = new FilterRegistrationBean<MyFilter>();
		//对所有请求都执行过滤
		filter.addUrlPatterns("/*");
		//指定执行的过滤器
		filter.setFilter(new MyFilter());
		return filter;	
	}

3. 启动项目，访问任意路径，控制台打印：

执行了过滤器

---

注册监听器Listener

1. 创建MyListener类

package com.blu.conf;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class MyListener implements ServletContextListener{

	@Override
	public void contextInitialized(ServletContextEvent sce) {
		System.out.println("容器启动了...");
		
	}

	@Override
	public void contextDestroyed(ServletContextEvent sce) {
		System.out.println("容器销毁了...");
		
	}

}

2. 在配置类中添加Bean

	/**
	 * 注册监听器
	 */
	
	@Bean
	public ServletListenerRegistrationBean<MyListener> myListener(){
		ServletListenerRegistrationBean<MyListener> bean 
			= new ServletListenerRegistrationBean<MyListener>(new MyListener());
		
		return bean;	
	}

3. 启动项目时，控制台打印：

容器启动了...

4. 终止项目时，控制台打印：

容器销毁了...