hibernate中使用annotation，怎么设定双向关联

package com.chk.model;import java.util.HashSet;import java.util.Set;import javax.persistence.Entity;import javax.persistence.FetchType;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.JoinColumn;import javax.persistence.ManyToOne;import javax.persistence.OneToMany;@Entitypublic class Orgnization {    private int id;    private String name;    private String sn;    private String description;    private Orgnization parent;// 父节点    private Set<Person> persons = new HashSet<Person>();// 子节点    @Id    @GeneratedValue    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getSn() {        return sn;    }    public void setSn(String sn) {        this.sn = sn;    }    public String getDescription() {        return description;    }    public void setDescription(String description) {        this.description = description;    }    @ManyToOne    public Orgnization getParent() {        return parent;    }    public void setParent(Orgnization parent) {        this.parent = parent;    }    @OneToMany(mappedBy = "org")    public Set<Person> getPersons() {        return persons;    }    public void setPersons(Set<Person> persons) {        this.persons = persons;    }}

package com.chk.model;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.ManyToOne;@Entitypublic class Person {    private int id;    private String name;    private String sex;    private String address;    private String duty;    private String phone;    private String description;    private Orgnization org;    @ManyToOne    public Orgnization getOrg() {        return org;    }    public void setOrg(Orgnization org) {        this.org = org;    }    @Id    @GeneratedValue    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getSex() {        return sex;    }    public void setSex(String sex) {        this.sex = sex;    }    public String getAddress() {        return address;    }    public void setAddress(String address) {        this.address = address;    }    public String getDuty() {        return duty;    }    public void setDuty(String duty) {        this.duty = duty;    }    public String getPhone() {        return phone;    }    public void setPhone(String phone) {        this.phone = phone;    }    public String getDescription() {        return description;    }    public void setDescription(String description) {        this.description = description;    }}

    @Test    public void loadtest() {        Configuration cfg = new Configuration().configure();        SessionFactory sf = cfg.buildSessionFactory();        Session s = sf.getCurrentSession();        s.beginTransaction();        Orgnization org1 = (Orgnization) s.get(Orgnization.class, 1);        Set set = org1.getPersons();        System.out.println(set.size());        for (Iterator iterator = set.iterator(); iterator.hasNext();) {            Orgnization org = (Orgnization) iterator.next();            System.out.println(org.getName());                    }        s.getTransaction().commit();    }