用@WebServlet和@WebFilter干掉web.xml

太过爱你忘了你带给我的痛 2022-12-10 02:27 128阅读 0赞

## 1: servlet3.0 ##

在servlet3.0引入了`@WebServlet`，`@WebFilter`等注解，可以代替在`web.xml`中通过`<servlet><filter>`等标签进行配置，从而可以摆脱掉web.xml，当然还有其它方式实现，具体延伸可以看[这里][Link 1]。

## 2: 实践出真知 ##

### 2.1：创建servlet ###

@WebServlet(urlPatterns = "/annotationServlet", loadOnStartup = 1)
    public class AnnotationServlet extends HttpServlet {
    
    	@Override
    	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    		resp.setContentType("text/plain");
    		PrintWriter out = resp.getWriter();
    		out.println("hello world annotation servlet 3.0");
    	}
    }

### 2.2：创建filter ###

@WebFilter(urlPatterns = { "/annotationServlet" })
    public class AnnotationFilter 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("annotation filter in servlet 3 by @WebFilter");
    	}
    
    	@Override
    	public void destroy() {
    	}
    }

### 2.3：测试 ###

*  启动
 *  浏览器访问  
    ![在这里插入图片描述][20200923150431250.jpg_pic_center]

## 最后：都让开，我要喝瑞幸 ##

![在这里插入图片描述][20200828090303329.png_pic_center]

[Link 1]: https://blog.csdn.net/wang0907/article/details/108711872
[20200923150431250.jpg_pic_center]: /images/20221123/6d36674a70d7452786f3f8c8b970aeaa.png
[20200828090303329.png_pic_center]: /images/20221123/e09e35c5b47d44f580a5b7c13a87ddb5.png