java.lang.NoClassDefFoundError 如何解决这个错误

Question

当我提交注册表时，注册 servlet 运行但是当我创建了一个休眠会话工厂的对象时，它给了我一个异常。“javax.servlet.ServletException：Servlet 执行抛出异常 org.apache.tomcat.websocket.server.WsFilter。 doFilter(WsFilter.java:52)"。请帮我从这个异常中找出来。

package login;

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

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

import org.hibernate.SessionFactory;

@WebServlet("/Registration")
public class Registration extends HttpServlet {
   private static final long serialVersionUID = 1L;

public Registration() {
    super();
    // TODO Auto-generated constructor stub
}


protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
     String username =  request.getParameter("username");
     String password =  request.getParameter("password");
     String name =  request.getParameter("name");

     User u = new User();
     u.setUsername(username);
     u.setPassword(password);
     u.setName(name);

     SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();

}

Answer 1

在类路径中添加最新的hibernate.jar