SpringBoot中使用Servlet与更改DispatcherServlet默认Url

周sir | 2017年6月17日 | springboot | 0 条评论 | 6999

Springboot开发web应用过程中要用到过滤Filter和监听器Listener,
Springboot的主Servlet为 DispatcherServlet，其默认的url-pattern为“/”。也许我们在应用中还需要定义更多的Servlet，该如何使用SpringBoot来完成呢？

在spring boot中添加自己的Servlet有两种方法，代码注册Servlet和注解自动注册（Filter和Listener也是如此）。

一、代码注册通过ServletRegistrationBean、 FilterRegistrationBean 和 ServletListenerRegistrationBean 获得控制。

也可以通过实现 ServletContextInitializer 接口直接注册。

1.实现MyServlet.java

public class MyServlet extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println(">>>>>>>>>>doGet()<<<<<<<<<<<");
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println(">>>>>>>>>>doPost()<<<<<<<<<<<");
    }

}

2.SpringBoot启动时代码注入Servlet

@SpringBootApplication
public class SpringBootSampleApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootSampleApplication.class, args);
    }

   /**
     * 修改DispatcherServlet默认配置
     *
     */
    @Bean
    public ServletRegistrationBean dispatcherRegistration(DispatcherServlet dispatcherServlet) {
        ServletRegistrationBean registration = new ServletRegistrationBean(dispatcherServlet);
        registration.getUrlMappings().clear();
        registration.addUrlMappings("*.do");
        registration.addUrlMappings("*.json");
        return registration;
    }

    /**
     * 使用代码注册Servlet（不需要@ServletComponentScan注解）
     */
    @Bean
    public ServletRegistrationBean servletRegistrationBean() {
        return new ServletRegistrationBean(new MyServlet(), "/xs/*");// ServletName默认值为首字母小写，即myServlet
    }
}

二、在 SpringBootApplication 上使用@ServletComponentScan 注解后，Servlet、Filter、Listener 可以直接通过 @WebServlet、@WebFilter、@WebListener 注解自动注册，无需其他代码。

1. 过滤器LoginFilter.java

@WebFilter(value="/*")
public class LoginFilter implements Filter {

        public LoginFilter() {
    	       System.out.println("过滤器初始化");
        }

	public void destroy() {
		 System.out.println("过滤器销毁");
	}

	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		// TODO Auto-generated method stub
		// place your code here
		  System.out.println("执行过滤操作>>>>>");
		// pass the request along the filter chain
		
		chain.doFilter(request, response);
	}
	
	public void init(FilterConfig fConfig) throws ServletException {
	}

}

2.SpringBoot启动类添加组件扫描注解@ServletComponentScan

@SpringBootApplication
@ServletComponentScan
public class Application {
	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}
}