Initial SessionFactory creation failedorg.hibernate.AnnotationException:
刚写的报错：
Initial SessionFactory creation failedorg.hibernate.AnnotationException: mappedBy reference an unknown target entity property: com.super120.Model.Operation.oper in com.super120.Model.Operation.operations
用的hibernate3.6.10
hibernateUtils类

public class HibernateUtils {



	private static final SessionFactory sessionFactory;



	static {

		try {

			Configuration cfg = new Configuration();

			sessionFactory = cfg.configure().buildSessionFactory();

		} catch (Throwable e) {

			System.err.println("Initial SessionFactory creation failed" + e);

			throw new ExceptionInInitializerError(e);

		}

	}



	public static SessionFactory getSessionFactory() {

		return sessionFactory;

	}



	public static Session getSession() {

		return sessionFactory.openSession();

	}



	public static void closeSession(Session session) throws HibernateException {

		if (session != null) {

			if (session.isOpen()) {

				session.close();

			}

		}

	}



	public static void rollback(Transaction tran) {

		try {

			if (tran != null) {

				tran.rollback();

			}

		} catch (HibernateException he) {

			System.out.println("Rollback faild." + he);

		}

	}

}

operation类:

package com.super120.Model;



import java.util.HashSet;

import java.util.Set;



import javax.persistence.CascadeType;

import javax.persistence.Entity;

import javax.persistence.FetchType;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

import javax.persistence.OneToMany;

import javax.persistence.Table;



@Entity

@Table(name="tb_Operation")

public class Operation {

	private int ID;

	

	private String OperationName;

	

	private String Description;

	

	private String Reserved;

	

	private Set<Operation> operations = new HashSet<Operation>();

	



	

	@Id

	@GeneratedValue(strategy = GenerationType.AUTO)

	public int getID() {

		return ID;

	}



	public void setID(int iD) {

		ID = iD;

	}



	

	

	@OneToMany(cascade={CascadeType.REMOVE},fetch=FetchType.EAGER,mappedBy="oper")

	public Set<Operation> getOperations() {

		return operations;

	}



	public void setOperations(Set<Operation> operations) {

		this.operations = operations;

	}



	

	public String getOperationName() {

		return OperationName;

	}



	public void setOperationName(String operationName) {

		OperationName&