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java:如何解析java.lang.noclassdeffounderror:javax/xml/bind/jaxbeException（34个答案）
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我使用eclipse创建了动态项目。在这个项目中，我添加了mysql数据库的hibernate配置。我将servlet用于crud操作。我知道在maven项目中，可以添加所需的依赖项，但不能用于web应用程序。我已经将java.persistence jar文件添加到lib文件夹中。这是项目结构。

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下面是hibernate代码。

package net.javaguides.usermanagement.utl;

import java.util.Properties;

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.cfg.Environment;
import org.hibernate.service.ServiceRegistry;

import net.javaguides.usermanagement.model.User;

/**
 * Java based configuration
 * @author ramesh Fadatare
 *
 */
public class HibernateUtil {
 private static SessionFactory sessionFactory;

 public static SessionFactory getSessionFactory() {
  if (sessionFactory == null) {
   try {
    Configuration configuration = new Configuration();

    // Hibernate settings equivalent to hibernate.cfg.xml's properties
    Properties settings = new Properties();
    settings.put(Environment.DRIVER, "com.mysql.jdbc.Driver");
    settings.put(Environment.URL, "jdbc:mysql://localhost:3306/demo?useSSL=false");
    settings.put(Environment.USER, "root");
    settings.put(Environment.PASS, "");
    settings.put(Environment.DIALECT, "org.hibernate.dialect.MySQL5Dialect");

    settings.put(Environment.SHOW_SQL, "true");

    settings.put(Environment.CURRENT_SESSION_CONTEXT_CLASS, "thread");

    settings.put(Environment.HBM2DDL_AUTO, "create-drop");

    configuration.setProperties(settings);
    configuration.addAnnotatedClass(User.class);

    ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
      .applySettings(configuration.getProperties()).build();
    System.out.println("Hibernate Java Config serviceRegistry created");
    sessionFactory = configuration.buildSessionFactory(serviceRegistry);
    return sessionFactory;

   } catch (Exception e) {
    e.printStackTrace();
   }
  }
  return sessionFactory;
 }
}

这是servlet。

package net.javaguides.usermanagement.web;

import java.io.IOException;
import java.sql.SQLException;
import java.util.List;

import javax.servlet.RequestDispatcher;
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 net.javaguides.usermanagement.dao.UserDao;
import net.javaguides.usermanagement.model.User;

/**
 * ControllerServlet.java
 * This servlet acts as a page controller for the application, handling all
 * requests from the user.
 * @email Ramesh Fadatare
 */

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

    public void init() {
        userDao = new UserDao();
    }

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

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        String action = request.getServletPath();

        try {
            switch (action) {
                case "/new":
                    showNewForm(request, response);
                    break;
                case "/insert":
                    insertUser(request, response);
                    break;
                case "/delete":
                    deleteUser(request, response);
                    break;
                case "/edit":
                    showEditForm(request, response);
                    break;
                case "/update":
                    updateUser(request, response);
                    break;
                default:
                    listUser(request, response);
                    break;
            }
        } catch (SQLException ex) {
            throw new ServletException(ex);
        }
    }

    private void listUser(HttpServletRequest request, HttpServletResponse response)
    throws SQLException, IOException, ServletException {
        List < User > listUser = userDao.getAllUser();
        request.setAttribute("listUser", listUser);
        RequestDispatcher dispatcher = request.getRequestDispatcher("user-list.jsp");
        dispatcher.forward(request, response);
    }

    private void showNewForm(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        RequestDispatcher dispatcher = request.getRequestDispatcher("user-form.jsp");
        dispatcher.forward(request, response);
    }

    private void showEditForm(HttpServletRequest request, HttpServletResponse response)
    throws SQLException, ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        User existingUser = userDao.getUser(id);
        RequestDispatcher dispatcher = request.getRequestDispatcher("user-form.jsp");
        request.setAttribute("user", existingUser);
        dispatcher.forward(request, response);

    }

    private void insertUser(HttpServletRequest request, HttpServletResponse response)
    throws SQLException, IOException {
        String name = request.getParameter("name");
        String email = request.getParameter("email");
        String country = request.getParameter("country");
        User newUser = new User(name, email, country);
        userDao.saveUser(newUser);
        response.sendRedirect("list");
    }

    private void updateUser(HttpServletRequest request, HttpServletResponse response)
    throws SQLException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        String name = request.getParameter("name");
        String email = request.getParameter("email");
        String country = request.getParameter("country");

        User user = new User(id, name, email, country);
        userDao.updateUser(user);
        response.sendRedirect("list");
    }

    private void deleteUser(HttpServletRequest request, HttpServletResponse response)
    throws SQLException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        userDao.deleteUser(id);
        response.sendRedirect("list");
    }
}

这是我运行应用程序时的结果。