springboot（九）注册Servlet三大组件--Servlet、Filter、Listener

蔚落 2023-02-28 04:21 12阅读 0赞

1.ServletRegistrationBean

2.FilterRegistrationBean

3.ServletListenerRegistrationBean

--------------------

### 1.ServletRegistrationBean ###

public class MyServlet extends HttpServlet {
    
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            doPost(req, resp);
        }
    
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            resp.getWriter().write("Hello World");
        }
    }

@Configuration
    public class MyServerConfig {
    
        @Bean
        public ServletRegistrationBean myServlet(){
            ServletRegistrationBean<MyServlet> registrationBean = new ServletRegistrationBean<>(new MyServlet(),"/myServlet");
            return registrationBean;
        }
    }

## ##

### **2.**FilterRegistrationBean ###

public class MyFilter implements Filter {
        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
    
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
            //需要做什么
            System.out.println(System.currentTimeMillis());
            filterChain.doFilter(servletRequest,servletResponse);
        }
    
        @Override
        public void destroy() {
    
        }
    }

@Configuration
    public class MyServerConfig {
    
        @Bean
        public FilterRegistrationBean myFilter() {
            FilterRegistrationBean<Filter> registrationBean = new FilterRegistrationBean<>();
            registrationBean.setFilter(new MyFilter());
            registrationBean.setUrlPatterns(Arrays.asList("/servlet","/filter"));
            return registrationBean;
        }
    
    }

### **3.**ServletListenerRegistrationBean ###

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

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