web.xml文件无效

问题遇到的现象和发生背景

最近学习servlet和filter遇到了一个问题:修改web.xml不起作用

问题相关代码，请勿粘贴截图

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
    <display-name>javaweb</display-name>
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.jsp</welcome-file>
        <welcome-file>default.htm</welcome-file> 
    </welcome-file-list>
    
    <servlet>
        <servlet-name>B1</servlet-name>
        <servlet-class>test1.B1</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>B1</servlet-name>
        <url-pattern>/B1</url-pattern>
    </servlet-mapping>
    
    <filter>
        <filter-name>B2</filter-name>
        <filter-class>test1.B2</filter-class>
        <init-param>
            <param-name>value</param-name>
            <param-value>value</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>B2</filter-name>
        <url-pattern>/test1/B2</url-pattern>
    </filter-mapping>
<!--         <filter>
        <filter-name>B</filter-name>
        <filter-class>test1.B</filter-class>
        <init-param>
            <param-name>count</param-name>
            <param-value>1</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>B</filter-name>
        <url-pattern>/test1/B</url-pattern>
    </filter-mapping> -->
</web-app>

servlet:

package test1;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;

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

/**
 * Servlet implementation class B1
 */
public class B1 extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public B1() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        Enumeration e = request.getHeaderNames();
        while (e.hasMoreElements()) {
            String name = (String)e.nextElement();
            out.print(name + "<br/>");
            String value = request.getHeader(name);
            out.print(value + "<br/>");
        }
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

filter:

package test1;

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 B2 implements Filter{
    
    @Override
    public void destroy() {
        
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        //打印任意内容测试
        System.out.println("使用doFilter()方法");
        //将请求传回过滤链
        chain.doFilter(request, response);
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        //获取初始化参数
        String value1 = filterConfig.getInitParameter("value");
        //输出初始化参数
        System.out.println("获取值为: " + value1);
    }

}

运行结果及报错内容

值获取不到,页面也访问不了,只能通过添加web注解的方式访问,谁知道怎么解决

设置的过滤器路径是/test1/B2

但是你访问的是/B1

都不是你需要过滤的路径他怎么起作用？