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

分手后的思念是犯贱 2023-05-22 12:25 20阅读 0赞

**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");
    	}
    }

1.  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;
    	}

1.  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() { 
    	
    	}
    }

1.  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;	
    	}

1.  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...");
    		
    	}
    
    }

1.  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;	
    	}

1.  启动项目时，控制台打印：

容器启动了...

1.  终止项目时，控制台打印：

容器销毁了...