我正在使用visualstudio代码编写基于tomcat的javaservlet和jsp的培训项目。现在我正在做日志工作。我的项目结构如下所示：

webapps
|----ROOT
     |----public
     |----WEB-INF
          |----classes
               |----FamilyTask
                    |----filters
                         |----AccessFilter.java
                         |----compile_filter.bat
                    |----lib
                         |----Log.java
                         |----compile_class.bat
                    |----servlets
                         |----compile_servlet.bat
                         |----LoginServlet.java
          |----lib
          |----web.xml

班级 AccessFilter.java 实现了测井系统。这是密码 AccessFilter.java :

package FamilyTask.filters;

import ...

import FamilyTask.lib.Log;

public class AccessFilter implements Filter 
{
    ...
    ...
    ...

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException 
    {

        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse res = (HttpServletResponse) response;
        String path = req.getServletPath();

        FamilyTask.lib.Log.Info("#INFO - Path :" + path + ", URL =" + req.getRequestURL());
        if( path.contains("/public") ||
            path.equals("/") || path.isEmpty() || path.equals("/index.jsp") ||
            (path.equals("/login") && req.getMethod().toLowerCase().equals("post")))
            chain.doFilter(request, response);
        else
            res.sendRedirect("/");

        return;
    }
}

代码 Log.java ：包familytask.lib；

import ...
...
import java.util.*;
import java.util.logging.*;
import javax.naming.*;

public class Log
{
    private static Boolean isInit = false;
    private static Logger LOGGER = null;
    private static Handler handler = null;

    private static void Init()
    {
        if(isInit && LOGGER != null)
            return ;

        try 
        {
            handler = new FileHandler("debug_log");
            LOGGER.addHandler(handler);
            handler.setLevel(Level.ALL);
            handler.close();
        }
        catch(IOException exc)
        {
            System.out.println("Error: Couldn't create or open Log file. Error message: " +  exc.getMessage());
        }
        isInit = true;

        return;
    }

    public static void Info(String message)
    {
        if(!isInit)
            Log.Init();

        System.out.println("Info: " + message);
        LOGGER.info("Info: " + message);
    }

    public static void Error(String message)
    {
        if(!isInit)
            Log.Init();

        System.out.println("Error: " + message);
        LOGGER.warning("Error: " + message);
    }
}

编译servlet/filter类的命令：

javac --release 8 -cp "D:\path\to\my\project\webapps\ROOT\WEB_INF\classes\";"D:\path\to\my\project\lib\servlet-api.jar" "<servlet or filter name>.java"

编译简单类的命令：

javac --release 8 -cp "D:\path\to\my\project\webapps\ROOT\WEB_INF\classes\" "<class name>.java"

编译结束时没有出现错误，但在运行时出现以下错误：

Exception
    javax.servlet.ServletException: При выполнении фильтра выброшено исключение
Root Cause
    java.lang.NoClassDefFoundError: FamilyTask/lib/Log
    FamilyTask.filters.AccessFilter.doFilter(AccessFilter.java:42)
Root Cause
java.lang.ClassNotFoundException: FamilyTask.lib.Log
    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1365)
    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1188)
    FamilyTask.filters.AccessFilter.doFilter(AccessFilter.java:42)