hibernate关联详解.doc

1、 一对一单向主键关联（很少用到）t_idCardid cardNo1 111111111111111112 2222222222222222t_personid name1 张三2 李四Person.java类关系：public class Person private int id;private String name;private IdCard idCard;public int getId() return id;public void setId(int id) this.id = id;public String getName() return name;public void setName(String name) = name;public IdCard getIdCard() return idCard;public void setIdCard(IdCard idCard) this.idCard = idCard;package com.bjpowernode.hibernate;public class IdCard private int id;private String cardNo;public int getId() return id;public void setId(int id) this.id = id;public String getCardNo() return cardNo;public void setCardNo(String cardNo) this.cardNo = cardNo;映射文件关联：Person.hbm.xmlidCard-IdCard.hbm.xml2、 一对一双向主键关联（用的也不多）t_idCardid cardNo1 111111111111111112 2222222222222222t_personid name1 张三2 李四Person.java类关系：public class Person private int id;private String name;private IdCard idCard;public int getId() return id;public void setId(int id) this.id = id;public String getName() return name;public void setName(String name) = name;public IdCard getIdCard() return idCard;public void setIdCard(IdCard idCard) this.idCard = idCard;public class IdCard private int id;private String cardNo;private Person person;public int getId() return id;public void setId(int id) this.id = id;public String getCardNo() return cardNo;public void setCardNo(String cardNo) this.cardNo = cardNo;public Person getPerson() return person;public void setPerson(Person person) this.person = person;映射文件关联：Person.hbm.xmlidCardIdCard.hbm.xml3、 一对一单向外键关联t_personid name idCard(unique)1 张三 1002 李四 101t_idCardid cardNo100 111111111111111101 22222222222222Person.java类关系：public class Person private int id;private String name;private IdCard idCard;public int getId() return id;public void setId(int id) this.id = id;public String getName() return name;public void setName(String name) = name;public IdCard getIdCard() return idCard;public void setIdCard(IdCard idCard) this.idCard = idCard;public class IdCard private int id;private String cardNo;public int getId() return id;public void setId(int id) this.id = id;public String getCardNo() return cardNo;public void setCardNo(String cardNo) this.cardNo = cardNo;Person.hbm.xmlIdCard.hbm.xml4、 一对一双向外键关联（用的不少）t_personid name idCard(unique)1 张三 1002 李四 101t_idCardid cardNo100 111111111111111101 22222222222222public class Person private int id;private String name;private IdCard idCard;public int getId() return id;public void setId(int id) this.id = id;public String getName() return name;public void setName(String name) = name;public IdCard getIdCard() return idCard;public void setIdCard(IdCard idCard) this.idCard = idCard;public class IdCard private int id;private String cardNo;private Person person;public int getId() return id;public void setId(int id) this.id = id;public String getCardNo() return cardNo;public void setCardNo(String cardNo) this.cardNo = cardNo;public Person getPerson() return person;public void setPerson(Person person) this.person = person;5. 一对多单向关联映射t_studentid name classesid1 张三 12 李四 1t_classesid name1 动力节点import java.util.Set;public class Classes private int id;private String name;private Set students;public int getId() return id;public void setId(int id) this.id = id;public String getName() return name;public void setName(String name) = name;public Set getStudents() return students;public void setStudents(Set students) this.students = students;public class Student private int id;private String name;public int getId() return id;public void setId(int id) this.id = id;public String getName() return name;public void setName(String name) = name;!- - 6. 一对多双向关联映射（最多）t_studentid name classesid1 张三 12 李四 1t_classesid name1 动力节点import java.util.Set;public class Classes private int id;private String name;private Set students;public int getId() return id;public void setId(int id) this.id = id;public String getName() return name;public void setName(String name) = name;public Set getStudents() return students;public void setStudents(Set students) this.students = students;public class Student private int id;private String name;private Classes classes;public int getId() return id;public void setId(int id) this.id = id;public String getName() return name;public void setName(String name) = name;public Classes getClasses() return classes;public void setClasses(Classes classes) this.classes = classes;!- - column=classesid 必须与key保持一致一下是几种用cascade和inverse联合使用插入数据的例子：方法一：（最佳方式）Class.hbm.xml文件：!- - 将维护权交给student，Student.hbm.xml:设置级联当保存student对象时，保存处在transient状态的class对象最佳插入数据方式：session = HibernateUtils.getSession();session.beginTransaction();Classes classes = new Classes();classes.setName(动力节点);Student student1 = new Student();student1.setName(张三);student1.setClasses(classes);session.save(student1);Student student2 = new Student();student2.setName(李四);student2.setClasses(classes);session.save(student2);session.getTransaction().commit();方法二：Class.hbm.xml: 维护权在class一端，加之又有cascade级联所以插入数据时如下：session = HibernateUtils.getSession();session.beginTransaction();Student student1 = new Student();student1.setName(张三);Student student2 = new Student();student2.setName(李四);Classes classes = new Classes();classes.setName(动力节点);Set students = new HashSet();students.add(student1);students.add(student2);classes.setStudents(students);session.save(classes);session.getTransaction().commit();执行语句：Hibernate: insert into Classes (name) values (?)Hibernate: insert into t_student (name, classesid) values (?, ?)Hibernate: insert into t_student (name, classesid) values (?, ?)Hibernate: update t_student set classesid=? where id=?Hibernate: update t_student set classesid=? where id=?多了两条更新语句7、 多对多双向关联映射（也很多）t_user_roleuser_id role_id1 11 22 12 22 33 33 4t_roleid name1 数据录入人员2 商务主管3 商务经理4 项目会计t_userid name1 张三2 李四3 王五public class User private int id;private String name;private Set roles;public int getId() return id;public void setId(int id) this.id = id;public String getName() return name;public void setName(String name) = name;public Set getRoles() return roles;public void setRoles(Set roles) this.roles = roles;public class Role private int id;private String name;public int getId() return id;public void setId(int id) this.id = id;public String getName() return name;public void setName(String name) = name;8、 联合主键映射：import java.io.Serializable;public class FiscalYearPeriodPK implements Serializable /核算年private int fiscalYear;/核算月private int fiscalPeriod;public int getFiscalYear() return fiscalYear;public void setFiscalYear(int fiscalYear) this.fiscalYear = fiscalYear;public int getFiscalPeriod() return fiscalPeriod;public void setFiscalPeriod(int fiscalPeriod) this.fiscalPeriod = fiscalPeriod;Overridepublic int hashCode() final int prime = 31;int result = 1;result = prime * result + fiscalPeriod;result = prime * result + fiscalYear;return result;Overridepublic boolean equals(Object obj) if (this = obj)return true;if (obj = null)return false;if (getClass() != obj.getClass()return false;final FiscalYearPeriodPK other = (FiscalYearPeriodPK) obj;if (fiscalPeriod != other.fiscalPeriod)return false;if (fiscalYear != other.fiscalYear)return false;return true;public class FiscalYearPeriod private FiscalYearPeriodPK fiscalYearPeriodPK;/开始日期private Date beginDate;/结束日期private Date endDate;/状态private String periodSts;public Date getBeginDate() return beginDate;public void setBeginDate(Date beginDate) this.beginDate = beginDate;public Date getEndDate() return endDate;public void setEndDate(Date endDate) this.endDate = endDate;public String getPeriodSts() return periodSts;public void setPeriodSts(String periodSts) this.periodSts = periodSts;public FiscalYearPeriodPK getFiscalYearPeriodPK() return fiscalYearPeriodPK;public void setFiscalYearPeriodPK(FiscalYearPeriodPK fiscalYearPeriodPK) this.fiscalYearPeriodPK = fiscalYearPeriodPK;public void testSave1() Session session = null;try session = HibernateUtils.getSession();session.beginTransaction();FiscalYearPeriod fiscalYearPeriod = new FiscalYearPeriod();/构造复合主键对象FiscalYearPeriodPK fiscalYearPeriodPK = new FiscalYearPeriodPK();fiscalYearPeriodPK.setFiscalYear(2009);fiscalYearPeriodPK.setFiscalPeriod(12);fiscalYearPeriod.setFiscalYearPeriodPK(fiscalYearPeriodPK);