component、composite、collection映射
1、component(组件)映射：在hibernate中,component是某个实体的逻辑组成部分，它与实体的根本区别是没有oid，component可以成为是值对象（DDD）采用component映射的好处：它实现了对象模型的细粒度划分，层次会更分明，复用率会更高//modelpublic class Contact {private String email;private String address;private String zipCode;private String contactTel;public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public String getAddress() {return address;}public void setAddress(String address) {this.address = address;}public String getZipCode() {return zipCode;}public void setZipCode(String zipCode) {this.zipCode = zipCode;}public String getContactTel() {return contactTel;}public void setContactTel(String contactTel) {this.contactTel = contactTel;}}public class User {private int id;private String name;private Contact contact;// 持有对contact的引用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 Contact getContact() {return contact;}public void setContact(Contact contact) {this.contact = contact;}}//User.hbm.xml<hibernate-mapping><class name="com.bjsxt.hibernate.User" table="t_user"><id name="id"><generator class="native"/></id><property name="name" length = "10"/><component name="contact"><!-- component映射联系类 --><property name="email" length = "10"/><property name="address" length = "10"/><property name="zipCode" length = "10"/><property name="contactTel" length = "10"/></component></class></hibernate-mapping>//testimport org.hibernate.Session;import junit.framework.TestCase;public class ComponentMappingTest extends TestCase {public void testSave1() {Session session = null;try {session = HibernateUtils.getSession();session.beginTransaction();User user = new User();user.setName("张三");Contact contact = new Contact();contact.setAddress("xxxxx");contact.setEmail("xx@rr.com");contact.setZipCode("1111111");contact.setContactTel("9999999");user.setContact(contact); //contact不是实体，是一个附属的类session.save(user); // update、save的对象为实体session.getTransaction().commit();}catch(Exception e) {e.printStackTrace();session.getTransaction().rollback();}finally {HibernateUtils.closeSession(session);}}}
2、复合（联合）主键映射：通常将复合主键相关的属性，单独放到一个类中
* 此类必须实现序列化接口
* 覆写hashcode和equals方法//modelimport java.io.Serializable;@SuppressWarnings("serial")public class FiscalYearPeriodPK implements Serializable { // 实现序列化接口//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;}}import java.util.Date;/** * 核算期间 * @author wangy * */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;}}//FiscalYearPeriod.hbm.xml<hibernate-mapping><class name="com.bjsxt.hibernate.FiscalYearPeriod" table="t_fiscal_year_period"><composite-id name="fiscalYearPeriodPK"><!-- 映射联合主键 --><key-property name="fiscalYear"/><key-property name="fiscalPeriod"/></composite-id><property name="beginDate"/><property name="endDate"/><property name="periodSts"/></class></hibernate-mapping>//testimport java.util.Date;import org.hibernate.Session;import junit.framework.TestCase;public class CompositeMappingTest extends TestCase {public void testSave1() {Session session = null;try {session = HibernateUtils.getSession();session.beginTransaction();FiscalYearPeriod fiscalYearPeriod = new FiscalYearPeriod();// 实体类FiscalYearPeriodPK pk = new FiscalYearPeriodPK(); // 主键附属类pk.setFiscalYear(2008);pk.setFiscalPeriod(8);fiscalYearPeriod.setFiscalYearPeriodPK(pk);fiscalYearPeriod.setBeginDate(new Date());fiscalYearPeriod.setEndDate(new Date());fiscalYearPeriod.setPeriodSts("Y");session.save(fiscalYearPeriod);session.getTransaction().commit();}catch(Exception e) {e.printStackTrace();session.getTransaction().rollback();}finally {HibernateUtils.closeSession(session);}}public void testLoad1() {Session session = null;try {session = HibernateUtils.getSession();session.beginTransaction();FiscalYearPeriodPK pk = new FiscalYearPeriodPK();pk.setFiscalYear(2008);pk.setFiscalPeriod(8);// 根据主键加载实体类FiscalYearPeriod fiscalYearPeriod = (FiscalYearPeriod)session.load(FiscalYearPeriod.class, pk);System.out.println(fiscalYearPeriod.getPeriodSts());session.getTransaction().commit();}catch(Exception e) {e.printStackTrace();session.getTransaction().rollback();}finally {HibernateUtils.closeSession(session);}}}
3、set、list、array、map//modelimport java.util.List;import java.util.Map;import java.util.Set;public class CollectionMapping {private int id;private String name;private Set<String> setValue;private List<String> listValue;private String[] arrayValue;private Map<String, String> mapValue;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[] getArrayValue() {return arrayValue;}public void setArrayValue(String[] arrayValue) {this.arrayValue = arrayValue;}public void setListValue(List<String> listValue) {this.listValue = listValue;}public List<String> getListValue() {return listValue;}public void setSetValue(Set<String> setValue) {this.setValue = setValue;}public Set<String> getSetValue() {return setValue;}public void setMapValue(Map<String, String> mapValue) {this.mapValue = mapValue;}public Map<String, String> getMapValue() {return mapValue;}}//CollectionMapping.hbm.xml<hibernate-mapping><class name="com.bjsxt.hibernate.CollectionMapping" table="t_CollectionMapping"><id name="id"><generator class="native"/></id><property name="name"/><set name="setValue" table="t_set_value"><!-- 映射集合Set，将CollectionMapping普通属性setValue映射成表 --><key column="set_id"/><!-- 增加字段set_id，作为外键指向t_CollectionMapping --><element type="string" column="set_value"/><!-- t_set_value表中保存集合Set的值 --></set><list name="listValue" table="t_list_value"><!-- List集合有顺序 --><key column="list_id"/><list-index column="list_index"/><!-- 加入索引，用于保证顺序 --><element type="string" column="list_value"/></list><array name="arrayValue" table="t_array_value"><!-- 数组有顺序 --><key column="array_id"/><list-index column="array_index"/><element type="string" column="array_value"/></array><map name="mapValue" table="t_map_value"><key column="map_id"/><map-key type="string" column="map_key"/><!-- key-value --><element type="string" column="map_value"/></map></class></hibernate-mapping>//testimport java.util.ArrayList;import java.util.HashMap;import java.util.HashSet;import java.util.List;import java.util.Map;import java.util.Set;import org.hibernate.Session;import junit.framework.TestCase;public class CollectionMappintTest extends TestCase {public void testSave1() {CollectionMapping c = new CollectionMapping();c.setName("xxx");Set<String> setValue = new HashSet<String>();setValue.add("a");setValue.add("b");c.setSetValue(setValue);List<String> listValue = new ArrayList<String>();listValue.add("c");listValue.add("d");c.setListValue(listValue);String[] arrayValue = new String[]{"e", "f"};c.setArrayValue(arrayValue);Map<String, String> mapValue = new HashMap<String, String>();mapValue.put("k1", "v1");mapValue.put("k2", "v2");c.setMapValue(mapValue);Session session = null;try { // 一般只需要包含会出异常代码session = HibernateUtils.getSession();session.beginTransaction();session.save(c);session.getTransaction().commit();}catch(Exception e) {e.printStackTrace();session.getTransaction().rollback();}finally {HibernateUtils.closeSession(session);}}public void testLoad1() {Session session = null;try {session = HibernateUtils.getSession();session.beginTransaction();//根据主键加载实体类CollectionMapping c = (CollectionMapping)session.load(CollectionMapping.class, 1);System.out.println("name=" + c.getName());System.out.println("setvalue=" + c.getSetValue());System.out.println("mapvalue=" + c.getMapValue());System.out.println("listvalue=" + c.getListValue());System.out.println("arrayValue=" + c.getArrayValue().length);session.getTransaction().commit();}catch(Exception e) {e.printStackTrace();session.getTransaction().rollback();}finally {HibernateUtils.closeSession(session);}}}
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