java.lang.NoClassDefoundError：无法初始化类com.dao.userdao

Question

public class UserDAO extends GenericDAO<User> {

   private static final long serialVersionUID = 1L;

   public UserDAO() {
       super(User.class);
   }

   public User findUserByEmail(String email) {
       Map<String, Object> parameters = new HashMap<String, Object>();
       parameters.put("email", email);

       return super.findOneResult(User.FIND_BY_EMAIL, parameters);
   }
}

UserFacade：

public class UserFacade {
   private UserDAO userDAO = new UserDAO();

    public User isValidLogin(String email, String password) {
        userDAO.beginTransaction();
        User user = userDAO.findUserByEmail(email);

        if (user == null || !user.getPassword().equals(password)) {
            return null;
        }

        return user;
   }
}

用户：

@Entity
@Table(name = "USERS")
@NamedQuery(name = "User.findUserByEmail", query = "select u from User u where u.email = :email")
public class User implements Serializable {

   private static final long serialVersionUID = 1L;

   public static final String FIND_BY_EMAIL = "User.findUserByEmail";

   @Id
   @GeneratedValue(strategy = GenerationType.AUTO)
   private int id;

   @Column(unique = true)
   private String email;
   private String password;
   private String name;
   @Enumerated(EnumType.STRING)
   private Role role;

   public int getId() {
       return id;
   }

   public void setId(int id) {
       this.id = id;
   }

   public String getEmail() {
       return email;
   }

   public void setEmail(String email) {
       this.email = email;
   }

   public String getPassword() {
       return password;
   }

   public void setPassword(String password) {
       this.password = password;
   }

   public String getName() {
       return name;
   }

   public void setName(String name) {
       this.name = name;
   }

   public Role getRole() {
       return role;
   }

   public void setRole(Role role) {
       this.role = role;
   }

   public boolean isAdmin() {
       return Role.ADMIN.equals(role);
   }

   public boolean isUser() {
       return Role.USER.equals(role);
   }

   @Override
   public int hashCode() {
       return getId();
   }

   @Override
   public boolean equals(Object obj) {
       if (obj instanceof User) {
           User user = (User) obj;
           return user.getId() == id;
       }

       return false;
   }
}

Answer 1

此错误与未找到类或未找到库有关，请尝试重新导入Hibernate和JPA的正确库。

请下载：http://hibernate.org/orm/

解压缩，并从ORM Hibernate的正确功能所需的Hibernate\lib\文件夹中复制所有JAR，并从Hibernate\lib\jpa中复制所有jars以实现include jpa。