Spring Boot入门——web相关配置

1、Servlet

　　引用HttpServlet接口，采用原生的Servlet进行请求响应

2、Listener

　　引用ServletContextListener，常用于Web缓存

3、Filter

　　引用Filter接口，常用于认证、日志、令牌等

4、实现

　　方案一：采用原生的Servlet3.0注解进行配置 @WebServlet、@WebListener、@WebFilter

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

@WebServlet(name="indexServlet", urlPatterns="/index")
public class IndexServlet extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("-------------IndexServlet doGet--------------");
        resp.getWriter().print("hello world!!!");
        resp.getWriter().flush();
        resp.getWriter().close();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // TODO Auto-generated method stub
        System.out.println("-------------IndexServlet doPost--------------");
        this.doGet(req, resp);
    }
}

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;

@WebListener
public class IndexListener implements ServletContextListener{

    @Override
    public void contextDestroyed(ServletContextEvent arg0) {
        // TODO Auto-generated method stub
        System.out.println("-------------IndexListener contextDestroyed--------------");
    }

    @Override
    public void contextInitialized(ServletContextEvent arg0) {
        // TODO Auto-generated method stub
        System.out.println("-------------IndexListener contextInitialized--------------");    
    }

}

　　方案二：采用自己SpringBoot配置bean的方式进行配置

　　　　SpringBoot提供三种bean：FilterRegistrationBean、ServletRegistrationBean、ServletListenerRegistrationBean分别对应原生的Filter、Servlet、Listener

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;

import com.wyl.common.IndexFilter;
import com.wyl.common.IndexListener;
import com.wyl.common.IndexServlet;

/**
 * Hello world!
 *
 */
@SpringBootApplication
//@ServletComponentScan
public class App 
{
    public static void main( String[] args )
    {
        System.out.println( "Hello World!" );
        SpringApplication.run(App.class, args);
    }

    //注册三个Bean即可
    @Bean
    public FilterRegistrationBean indexFilter(){
        FilterRegistrationBean filter = new FilterRegistrationBean(new IndexFilter());
        filter.addUrlPatterns("/");
        return filter;
    }
    @Bean
    public ServletRegistrationBean indexServlet(){
        ServletRegistrationBean servlet = new ServletRegistrationBean(new IndexServlet());
        servlet.addUrlMappings("/index");
        return servlet;
    }
    @Bean
    public ServletListenerRegistrationBean indexListener(){
        ServletListenerRegistrationBean listener = new ServletListenerRegistrationBean(new IndexListener());
        return listener;
    }
}

　　注：只需要修改App.class文件中的内容即可，其他内容参见方案一