实体配置如下:

[code="java"]package com;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;

/**

• Department entity.

• @author MyEclipse Persistence Tools
  */
  @Entity
  @Table
  public class Department implements java.io.Serializable {

  // Fields
  @Id
  private Long depid;
  private String depname;
  @OneToMany(mappedBy="department")
  private Set employees = new HashSet();
  // Constructors

  /** default constructor */
  public Department() {
  }

  /** minimal constructor */
  public Department(Long depid) {
  this.depid = depid;
  }

  /** full constructor */
  public Department(Long depid, String depname) {
  this.depid = depid;
  this.depname = depname;
  }

  // Property accessors

  public Long getDepid() {
  return this.depid;
  }

  public void setDepid(Long depid) {
  this.depid = depid;
  }

  public String getDepname() {
  return this.depname;
  }

  public void setDepname(String depname) {
  this.depname = depname;
  }

  public Set getEmployees() {
  return employees;
  }

  public void setEmployees(Set employees) {
  this.employees = employees;
  }

}[/code]
[code="java"]package com;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

/**

• Employee entity.
• @author MyEclipse Persistence Tools */ @Entity @Table

public class Employee implements java.io.Serializable {

// Fields
@Id
private Long eeid;
private String eename;
@Column(name="dep_id",insertable=false,updatable=false)
private Long depId;
@ManyToOne(cascade=CascadeType.ALL)
@JoinColumn(name="dep_id")
private Department department;
// Constructors

/** default constructor */
public Employee() {
}

/** minimal constructor */
public Employee(Long eeid) {
    this.eeid = eeid;
}

/** full constructor */
public Employee(Long eeid, String eename, Long depId) {
    this.eeid = eeid;
    this.eename = eename;
    this.depId = depId;
}

// Property accessors

public Long getEeid() {
    return this.eeid;
}

public void setEeid(Long eeid) {
    this.eeid = eeid;
}

public String getEename() {
    return this.eename;
}

public void setEename(String eename) {
    this.eename = eename;
}

public Long getDepId() {
    return this.depId;
}

public void setDepId(Long depId) {
    this.depId = depId;
}

public Department getDepartment() {
    return department;
}

public void setDepartment(Department department) {
    this.department = department;
}

}[/code]

:( 请lz还是把自己的源码贴出来，让大家分析下

mapped用于指定在双向关系中两个实体中被哪个实体是被关联处理的.

在你的department和employee的一对多关系中,当你指定department中的mappedBy后,你的关系只能被employee来主动维护.也就是employee级联的处理department.

一对多单向关联(多方维护):
[code="java"]
package com;

import java.util.HashSet;
import java.util.Set;

import org.hibernate.Session;

/*

• created time:上午11:44:11

• creator: Tian Zhichao (chinoistzc@gmail.com)
  *
  */
  public class Test {

  /**

  • main()

  • 2010-4-5,上午11:44:11
    */
    public static void main(String[] args) {
    // TODO Auto-generated method stub
    Session session = HibernateSessionFactory.getSession();
    session.beginTransaction();
    Department dep = new Department();

    dep.setDepid(123L);
    dep.setDepname("dep name");
    Employee ee1 = new Employee();
    Employee ee2 = new Employee();
    ee1.setEeid(1L);
    ee1.setDepartment(dep);
    ee2.setEeid(2L);
    ee2.setDepartment(dep);
    Set employees = new HashSet();
    employees.add(ee1);
    employees.add(ee2);
    dep.setEmployees(employees);
    session.save(ee1);
    session.save(ee2);
    session.getTransaction().commit();
    System.out.println("-----------------用一端来保存时....");
    session.beginTransaction();
    Department dep2 = new Department();
    dep2.setDepid(100L);
    dep2.setEmployees(employees);
    session.save(dep2);
    session.getTransaction().commit();
    session.close();
    }

}

[/code]
Hibernate打印输出的:
[code="java"]log4j:WARN No appenders could be found for logger (org.hibernate.cfg.annotations.Version).
log4j:WARN Please initialize the log4j system properly.
Hibernate:
select
department_.depid,
department_.depname as depname1_
from
Department department_
where
department_.depid=?
Hibernate:
insert
into
Department
(depname, depid)
values
(?, ?)
Hibernate:
insert
into
Employee
(dep_id, eename, eeid)
values
(?, ?, ?)
Hibernate:
insert
into
Employee
(dep_id, eename, eeid)
values
(?, ?, ?)
-----------------用一端来保存时....
Hibernate:
insert
into
Department
(depname, depid)
values
(?, ?)
[/code]

下面这个显示了只department,做为被维护端时,如果保存它,Hibernate会只保存它自已.
[code="java"]
package com;

import java.util.HashSet;
import java.util.Set;

import org.hibernate.Session;

/*

• created time:上午11:44:11

• creator: Tian Zhichao (chinoistzc@gmail.com)
  *
  */
  public class Test {

  /**

  • main()

  • 2010-4-5,上午11:44:11
    */
    public static void main(String[] args) {
    // TODO Auto-generated method stub
    Session session = HibernateSessionFactory.getSession();
    session.beginTransaction();
    Department dep = new Department();

    dep.setDepid(123L);
    dep.setDepname("dep name");
    Employee ee1 = new Employee();
    Employee ee2 = new Employee();
    ee1.setEeid(1L);
    ee1.setDepartment(dep);
    ee2.setEeid(2L);
    ee2.setDepartment(dep);
    Set employees = new HashSet();
    employees.add(ee1);
    employees.add(ee2);
    dep.setEmployees(employees);
    session.save(dep);
    session.getTransaction().commit();
    session.close();
    }

}
[/code]
[code="java"]log4j:WARN No appenders could be found for logger (org.hibernate.cfg.annotations.Version).
log4j:WARN Please initialize the log4j system properly.
Hibernate:
insert
into
Department
(depname, depid)
values
(?, ?)
[/code]

[size=x-large][color=red]希望对你有帮助..[/color][/size]