Hibernate和JPA使用连接表处理多对一映射

于 2009-01-09 17:34:00 发布 · 159 阅读 · 0
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#java #数据库

本文介绍如何使用JPA和Hibernate实现多对一及多对多的关系映射，包括实体类定义与配置文件详解。

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在项目中，原有的持久化操作时使用JPA进行的，通过注解多对一映射被映射成中间表和两个数据库表，其代码如下：

  1. importjavax.persistence.Column;
  2. importjavax.persistence.Entity;
  3. importjavax.persistence.GeneratedValue;
  4. importjavax.persistence.GenerationType;
  5. importjavax.persistence.Id;
  6. importjavax.persistence.NamedQueries;
  7. importjavax.persistence.NamedQuery;
  8. importjavax.persistence.Table;
  10. /**
  11. *产品实体类
  12. *@author李文锴
  13. */
  14. @Entity
  15. @Table(name="yunda_product")
  16. @NamedQueries({
  17. @NamedQuery(name="getProduct",query="SELECTpFROMOrderProductASp"),
  18. @NamedQuery(name="getProductByName",query="SELECTpFROMOrderProductASpWHEREp.name=:name")
  19. })
  20. publicclassOrderProductimplementsjava.io.Serializable{
  22. privatestaticfinallongserialVersionUID=1L;
  23. /**
  24. *货物id
  25. */
  26. @Id
  27. @GeneratedValue(strategy=GenerationType.AUTO)
  28. privateLongid;
  29. /**
  30. *货物名称
  31. */
  32. @Column(name="p_name",length=80,nullable=false)
  33. privateStringname;
  34. /**
  35. *货物类型
  36. */
  37. @Column(name="p_type",length=80,nullable=false)
  38. privateStringtype;
  39. /**
  40. *货物数量
  41. */
  42. @Column(name="p_quantity",nullable=false)
  43. privateintquantity;
  45. publicOrderProduct(){
  46. }
  48. publicOrderProduct(Stringname,Stringtype,intquantity){
  49. setName(name);
  50. setType(type);
  51. setQuantity(quantity);
  52. }
  54. publicLonggetId(){
  55. returnid;
  56. }
  58. publicvoidsetId(Longid){
  59. this.id=id;
  60. }
  62. publicStringgetName(){
  63. returnname;
  64. }
  66. publicvoidsetName(Stringname){
  67. this.name=name;
  68. }
  70. publicintgetQuantity(){
  71. returnquantity;
  72. }
  74. publicvoidsetQuantity(intquantity){
  75. this.quantity=quantity;
  76. }
  78. publicStringgetType(){
  79. returntype;
  80. }
  82. publicvoidsetType(Stringtype){
  83. this.type=type;
  84. }
  86. @Override
  87. publicbooleanequals(Objectobj){
  88. if(obj==null){
  89. returnfalse;
  90. }
  91. if(getClass()!=obj.getClass()){
  92. returnfalse;
  93. }
  94. finalOrderProductother=(OrderProduct)obj;
  95. if((this.name==null)?(other.name!=null):!this.name.equals(other.name)){
  96. returnfalse;
  97. }
  98. if((this.type==null)?(other.type!=null):!this.type.equals(other.type)){
  99. returnfalse;
  100. }
  101. if(this.quantity!=other.quantity){
  102. returnfalse;
  103. }
  104. returntrue;
  105. }
  107. @Override
  108. publicinthashCode(){
  109. inthash=7;
  110. hash=61*hash+(this.name!=null?this.name.hashCode():0);
  111. hash=61*hash+(this.type!=null?this.type.hashCode():0);
  112. hash=61*hash+this.quantity;
  113. returnhash;
  114. }
  115. }

  1. importjava.util.Date;
  2. importjava.util.Set;
  3. importjavax.persistence.CascadeType;
  4. importjavax.persistence.Column;
  5. importjavax.persistence.Entity;
  6. importjavax.persistence.GeneratedValue;
  7. importjavax.persistence.GenerationType;
  8. importjavax.persistence.Id;
  9. importjavax.persistence.JoinColumn;
  10. importjavax.persistence.JoinTable;
  11. importjavax.persistence.OneToMany;
  12. importjavax.persistence.Table;
  13. importjavax.persistence.Temporal;
  15. /**
  16. *存储订单实体类，其中和产品实体进行关联
  17. *@author李文锴
  18. */
  19. @Entity
  20. @Table(name="stock_order")
  21. publicclassStockOrderimplementsjava.io.Serializable{
  23. privatestaticfinallongserialVersionUID=1L;
  24. /**
  25. *订单id
  26. */
  27. @Id
  28. @GeneratedValue(strategy=GenerationType.AUTO)
  29. privateLongid;
  30. /**
  31. *客户编号
  32. */
  33. @Column(name="customer_no",length=20,nullable=false)
  34. privateStringcustomerNO;
  35. /**
  36. *客户名称
  37. */
  38. @Column(name="customer_name",length=80,nullable=false)
  39. privateStringcustomerName;
  40. /**
  41. *产品
  42. */
  43. @OneToMany(cascade=CascadeType.ALL)
  44. @JoinTable(name="stock_order_product",joinColumns={@JoinColumn(name="stock_order_id")},inverseJoinColumns={@JoinColumn(name="product_id")})
  45. privateSet<OrderProduct>prdoucts;
  46. /**
  47. *到达日期
  48. */
  49. @Column(name="arrival_date",nullable=false)
  50. @Temporal(javax.persistence.TemporalType.DATE)
  51. privateDatearrivalDate;
  53. publicStockOrder(){
  54. }
  56. publicStockOrder(StringcustomerNO,StringcustomerName,Set<OrderProduct>prdoucts,DatearrivalDate){
  57. setCustomerNO(customerNO);
  58. setCustomerName(customerName);
  59. setPrdoucts(prdoucts);
  60. setArrivalDate(arrivalDate);
  61. }
  63. publicDategetArrivalDate(){
  64. returnarrivalDate;
  65. }
  67. publicvoidsetArrivalDate(DatearrivalDate){
  68. this.arrivalDate=arrivalDate;
  69. }
  71. publicStringgetCustomerNO(){
  72. returncustomerNO;
  73. }
  75. publicvoidsetCustomerNO(StringcustomerNO){
  76. this.customerNO=customerNO;
  77. }
  79. publicLonggetId(){
  80. returnid;
  81. }
  83. publicvoidsetId(Longid){
  84. this.id=id;
  85. }
  87. publicSet<OrderProduct>getPrdoucts(){
  88. returnprdoucts;
  89. }
  91. publicvoidsetPrdoucts(Set<OrderProduct>prdoucts){
  92. this.prdoucts=prdoucts;
  93. }
  95. publicStringgetCustomerName(){
  96. returncustomerName;
  97. }
  99. publicvoidsetCustomerName(StringcustomerName){
  100. this.customerName=customerName;
  101. }
  103. @Override
  104. publicbooleanequals(Objectobj){
  105. if(obj==null){
  106. returnfalse;
  107. }
  108. if(getClass()!=obj.getClass()){
  109. returnfalse;
  110. }
  111. finalStockOrderother=(StockOrder)obj;
  112. if((this.customerNO==null)?(other.customerNO!=null):!this.customerNO.equals(other.customerNO)){
  113. returnfalse;
  114. }
  115. if((this.customerName==null)?(other.customerName!=null):!this.customerName.equals(other.customerName)){
  116. returnfalse;
  117. }
  118. if(this.prdoucts!=other.prdoucts&&(this.prdoucts==null||!this.prdoucts.equals(other.prdoucts))){
  119. returnfalse;
  120. }
  121. if(this.arrivalDate!=other.arrivalDate&&(this.arrivalDate==null||!this.arrivalDate.equals(other.arrivalDate))){
  122. returnfalse;
  123. }
  124. returntrue;
  125. }
  127. @Override
  128. publicinthashCode(){
  129. inthash=5;
  130. hash=59*hash+(this.customerNO!=null?this.customerNO.hashCode():0);
  131. hash=59*hash+(this.customerName!=null?this.customerName.hashCode():0);
  132. hash=59*hash+(this.prdoucts!=null?this.prdoucts.hashCode():0);
  133. hash=59*hash+(this.arrivalDate!=null?this.arrivalDate.hashCode():0);
  134. returnhash;
  135. }
  136. }
  1. importjava.util.Date;
  2. importjava.util.Set;
  3. importjavax.persistence.CascadeType;
  4. importjavax.persistence.Column;
  5. importjavax.persistence.Entity;
  6. importjavax.persistence.GeneratedValue;
  7. importjavax.persistence.GenerationType;
  8. importjavax.persistence.Id;
  9. importjavax.persistence.JoinColumn;
  10. importjavax.persistence.JoinTable;
  11. importjavax.persistence.OneToMany;
  12. importjavax.persistence.Table;
  13. importjavax.persistence.Temporal;
  15. /**
  16. *运输订单实体类，并于产品实体进行关联
  17. *@author李文锴
  18. */
  19. @Entity
  20. @Table(name="trans_order")
  21. publicclassTransOrderimplementsjava.io.Serializable{
  23. privatestaticfinallongserialVersionUID=1L;
  24. /**
  25. *订单id
  26. */
  27. @Id
  28. @GeneratedValue(strategy=GenerationType.AUTO)
  29. privateLongid;
  30. /**
  31. *客户编号
  32. */
  33. @Column(name="customer_no",length=20,nullable=false)
  34. privateStringcustomerNO;
  35. /**
  36. *客户名称
  37. */
  38. @Column(name="customer_name",length=80,nullable=false)
  39. privateStringcustomerName;
  40. /**
  41. *产品
  42. */
  43. @OneToMany(cascade=CascadeType.ALL)
  44. @JoinTable(name="trans_order_product",joinColumns={@JoinColumn(name="trans_order_id")},inverseJoinColumns={@JoinColumn(name="product_id")})
  45. privateSet<OrderProduct>prdoucts;
  46. /**
  47. *其实地址
  48. */
  49. @Column(name="start_address",length=80,nullable=false)
  50. privateStringstartAddress;
  51. /**
  52. *目的地址
  53. */
  54. @Column(name="end_address",length=80,nullable=false)
  55. privateStringendAddress;
  56. /**
  57. *运输日期
  58. */
  59. @Column(name="trans_date",nullable=false)
  60. @Temporal(javax.persistence.TemporalType.DATE)
  61. privateDatetransportationDate;
  63. publicTransOrder(){
  64. }
  66. publicTransOrder(StringcustomerNO,StringcustomerName,Set<OrderProduct>prdoucts,StringstartAddress,StringendAddress,DatetransportationDate){
  67. setCustomerNO(customerNO);
  68. setCustomerName(customerName);
  69. setPrdoucts(prdoucts);
  70. setStartAddress(startAddress);
  71. setEndAddress(endAddress);
  72. setTransportationDate(transportationDate);
  73. }
  75. publicDategetTransportationDate(){
  76. returntransportationDate;
  77. }
  79. publicvoidsetTransportationDate(DatetransportationDate){
  80. this.transportationDate=transportationDate;
  81. }
  83. publicStringgetCustomerNO(){
  84. returncustomerNO;
  85. }
  87. publicvoidsetCustomerNO(StringcustomerNO){
  88. this.customerNO=customerNO;
  89. }
  91. publicLonggetId(){
  92. returnid;
  93. }
  95. publicvoidsetId(Longid){
  96. this.id=id;
  97. }
  99. publicSet<OrderProduct>getPrdoucts(){
  100. returnprdoucts;
  101. }
  103. publicvoidsetPrdoucts(Set<OrderProduct>prdoucts){
  104. this.prdoucts=prdoucts;
  105. }
  107. publicStringgetCustomerName(){
  108. returncustomerName;
  109. }
  111. publicvoidsetCustomerName(StringcustomerName){
  112. this.customerName=customerName;
  113. }
  115. publicStringgetEndAddress(){
  116. returnendAddress;
  117. }
  119. publicvoidsetEndAddress(StringendAddress){
  120. this.endAddress=endAddress;
  121. }
  123. publicStringgetStartAddress(){
  124. returnstartAddress;
  125. }
  127. publicvoidsetStartAddress(StringstartAddress){
  128. this.startAddress=startAddress;
  129. }
  131. @Override
  132. publicbooleanequals(Objectobj){
  133. if(obj==null){
  134. returnfalse;
  135. }
  136. if(getClass()!=obj.getClass()){
  137. returnfalse;
  138. }
  139. finalTransOrderother=(TransOrder)obj;
  140. if((this.customerNO==null)?(other.customerNO!=null):!this.customerNO.equals(other.customerNO)){
  141. returnfalse;
  142. }
  143. if((this.customerName==null)?(other.customerName!=null):!this.customerName.equals(other.customerName)){
  144. returnfalse;
  145. }
  146. if(this.prdoucts!=other.prdoucts&&(this.prdoucts==null||!this.prdoucts.equals(other.prdoucts))){
  147. returnfalse;
  148. }
  149. if((this.startAddress==null)?(other.startAddress!=null):!this.startAddress.equals(other.startAddress)){
  150. returnfalse;
  151. }
  152. if((this.endAddress==null)?(other.endAddress!=null):!this.endAddress.equals(other.endAddress)){
  153. returnfalse;
  154. }
  155. if(this.transportationDate!=other.transportationDate&&(this.transportationDate==null||!this.transportationDate.equals(other.transportationDate))){
  156. returnfalse;
  157. }
  158. returntrue;
  159. }
  161. @Override
  162. publicinthashCode(){
  163. inthash=3;
  164. hash=79*hash+(this.customerNO!=null?this.customerNO.hashCode():0);
  165. hash=79*hash+(this.customerName!=null?this.customerName.hashCode():0);
  166. hash=79*hash+(this.prdoucts!=null?this.prdoucts.hashCode():0);
  167. hash=79*hash+(this.startAddress!=null?this.startAddress.hashCode():0);
  168. hash=79*hash+(this.endAddress!=null?this.endAddress.hashCode():0);
  169. hash=79*hash+(this.transportationDate!=null?this.transportationDate.hashCode():0);
  170. returnhash;
  171. }
  172. }

先要使用Hibernate对其进行映射，由于产生了中间表，所以它的配置文件有些不同，如下：

  1. <?xmlversion="1.0"encoding="UTF-8"?>
  2. <!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  3. <hibernate-mapping>
  4. <classname="com.yunda.dao.domain.Product"table="yunda_product">
  5. <idname="id"type="long">
  6. <generatorclass="native"/>
  7. </id>
  8. <propertyname="name"column="p_name"type="string"length="80"not-null="true"/>
  9. <propertyname="type"column="p_type"type="string"length="80"not-null="true"/>
  10. <propertyname="quantity"column="p_quantity"type="integer"length="80"not-null="true"/>
  11. <!--使用join来配置多对一的连接,以table属性来表示连接表的多对一，连接表为stock_order_id-->
  12. <!--optional属性表示这是一个外连接,inverse属性可以出现在一端和多端，这里选择出现在多端，效果相同-->
  13. <jointable="stock_order_product"optional="true"inverse="true">
  14. <!--该key的字段为连接表中的字段，作为外键-->
  15. <keycolumn="product_id"/>
  16. <!--连接表中配置多对一，对应的字段为stock_order_id-->
  17. <many-to-onename="stockOrder"column="stock_order_id"not-null="true"/>
  18. </join>
  19. <!--使用join来配置多对一的连接,以table属性来表示连接表的多对一，连接表为trans_order_id-->
  20. <!--optional属性表示这是一个外连接,inverse属性可以出现在一端和多端，这里选择出现在多端，效果相同-->
  21. <jointable="trans_order_product"optional="true"inverse="true">
  22. <!--该key的字段为连接表中的字段，作为外键-->
  23. <keycolumn="product_id"/>
  24. <!--连接表中配置多对一，对应的字段为trans_order_id-->
  25. <many-to-onename="transOrder"column="trans_order_id"not-null="true"/>
  26. </join>
  27. </class>
  28. </hibernate-mapping>

  1. <?xmlversion="1.0"encoding="UTF-8"?>
  2. <!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  3. <hibernate-mapping>
  4. <classname="com.yunda.dao.domain.StockOrder"table="stock_order">
  5. <idname="id"type="long">
  6. <generatorclass="native"/>
  7. </id>
  8. <propertyname="customerNO"column="customer_no"type="string"length="20"not-null="true"/>
  9. <propertyname="customerName"column="customer_name"type="string"length="80"not-null="true"/>
  10. <propertyname="arrivalDate"column="arrival_date"type="date"not-null="true"/>
  11. <!--通过连接表的一端，因此需要table属性为stock_order_product-->
  12. <setname="prdoucts"cascade="all"table="stock_order_product"lazy="false">
  13. <!--该key的字段为连接表中的字段，作为外键-->
  14. <keycolumn="stock_order_id"/>
  15. <!--配置多对多-->
  16. <!--但是unique属性为true,表示product_id字段为不可重复,保证一对多关系-->
  17. <many-to-manyclass="com.yunda.dao.domain.Product"column="product_id"unique="true"/>
  18. </set>
  19. </class>
  20. </hibernate-mapping>

  1. <?xmlversion="1.0"encoding="UTF-8"?>
  2. <!DOCTYPEhibernate-mappingPUBLIC"-//Hibernate/HibernateMappingDTD3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
  3. <hibernate-mapping>
  4. <classname="com.yunda.dao.domain.TransOrder"table="trans_order">
  5. <idname="id"type="long">
  6. <generatorclass="native"/>
  7. </id>
  8. <propertyname="customerNO"column="customer_no"type="string"length="20"not-null="true"/>
  9. <propertyname="customerName"column="customer_name"type="string"length="80"not-null="true"/>
  10. <propertyname="startAddress"column="start_address"type="string"length="80"not-null="true"/>
  11. <propertyname="endAddress"column="end_address"type="string"length="80"not-null="true"/>
  12. <propertyname="transportationDate"column="trans_date"type="date"not-null="true"/>
  13. <!--通过连接表的一端，因此需要table属性为stock_order_product-->
  14. <setname="prdoucts"cascade="all"table="trans_order_product"lazy="false">
  15. <!--该key的字段为连接表中的字段，作为外键-->
  16. <keycolumn="trans_order_id"/>
  17. <!--配置多对多-->
  18. <!--但是unique属性为true,表示product_id字段为不可重复,保证一对多关系-->
  19. <many-to-manyclass="com.yunda.dao.domain.Product"column="product_id"unique="true"/>
  20. </set>
  21. </class>
  22. </hibernate-mapping>

iteye_13254
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