参见英文答案 > java.lang.NoClassDefFoundError: javax/servlet/http/HttpServletRequest                                    4个
我是Tomcat servlet编码的新手,我收到了这个错误：

> java.lang.NoClassDefFoundError: javax/servlet/http/HttpServletRequest
-> `servlet-api.jar` is in lib `tomcat_root/lib` dirctory 

CATALINA_HOME = C:\tomcat\lib\;
JAVA_HOME = C:\Program Files\Java\jdk1.7.0_01
Path = ....;%JAVA_HOME%\bin;%JAVA_HOME%;...

我很困惑,因为javac正在编译代码而没有任何错误.

这是我正在使用的代码 – 你能告诉导致错误的是什么吗？我不能.

package com.life;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class Task10 extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, java.io.IOException {
        try {
            response.setContentType("text/html");
            java.io.PrintWriter out = response.getWriter();

            File destinationDir;
            String realPath = getServletContext().getRealPath("/files");
            destinationDir = new File(realPath);
            DiskFileItemFactory  fileItemFactory = new DiskFileItemFactory ();
            ServletFileUpload uploadHandler = new ServletFileUpload(fileItemFactory);
            if (ServletFileUpload.isMultipartContent(request)) {
                List items = uploadHandler.parseRequest(request);
            }
            out.println(ServletFileUpload.isMultipartContent(request));
            out.println(realPath);
            out.close();
        }
        catch(Exception ex) {
            log("Error encountered while uploading file",ex);
        }


    }


    protected void doPost(HttpServletRequest request,
                          HttpServletResponse response) throws ServletException,
        java.io.IOException {
        doGet(request, response);
    }
}

解决方法:

在CMD中试试这个：

SET CATALINA_HOME = C:\Program Files\Apache Software Foundation\Tomcat 7.0;C:\Program Files\Apache Software Foundation\Tomcat 7.0\lib;

(在当前版本TOMCAT 7.0)