Hibernate 多表关联查询示例
Hibernate HSQL多表关联查询示例：
TSettlementPaymentRec,TIsvSettlement,TC001CorpMessage三个java Bean映射于T_Isv_Settlement，T_Isv_Settlement_Attach , T_C001_Corp_Messag表
其中T_Isv_Settlement，T_Isv_Settlement_Attach , T_C001_Corp_Messag 已经有主外键关联关系，所以在where条件中用
‘ AND t.TIsvSettlement=t2 AND t2.TC001CorpMessage=t3’表示关联关系。
testHSQL(){
String HSQL=" select t.voucherno, t2.memo, t3.name
FROM TSettlementPaymentRec t , TIsvSettlement t2 , TC001CorpMessage t3 " +
" WHERE t2.settlementid = 'S2011042000066' AND t.TIsvSettlement=t2 AND t2.TC001CorpMessage=t3";
List ltest=this.findByHSQL(HSQL);
}
/**
* 根据HQL查询字符串来返回实例集合对象
*
* @param querySql HQL查询字符串
*
* @return 返回object
*/
public List findByHSQL(final String querySql) {
try {
List obj = getHibernateTemplate().find(querySql);
if (obj != null) {
return obj;
} else {
return null;
}
} catch (RuntimeException re) {
throw re;
}
}
=========================================================================
各文件属性定义（部分）
TSettlementPaymentRec.java:
public class TSettlementPaymentRec implements java.io.Serializable {
// Fields
private String paymentid;
private TIsvSettlement TIsvSettlement;
private Double settlementnum;
private Double amount;
private String voucherno;
private String paymenttype;
private Date paymenttime;
private String userid;
private String source;
}
TC001CorpMessage.java:
public class TC001CorpMessage implements java.io.Serializable {
// Fields
private String userid;
private String name;
private String password;
private String email;
private String type;
private String corpname;
private String commaddress;
private String commcall;
private Integer zipcode;
private String orgcode;
private String registcode;
private String registaddress;
private String legalname;
private String fax;
private String contact;
private String username;
private String identity;
private String mobile;
private String industry;
private BigDecimal integrity;
private BigDecimal credit;
private BigDecimal settlespan;
private Date createtime;
}
TIsvSettlement.java
public class TIsvSettlement implements java.io.Serializable {
// Fields
private String settlementid;
private TC001CorpMessage TC001CorpMessage;
private Double settlementnum;
private Double sum;
private Date settlementTime;
private String sendmState;
private Date sendmTime;
private String sendmId;
private String receivemState;
private Date receivemTime;
private String recrivemId;
private String state;
private String memo;
private Set TIsvSettlementAttachs = new HashSet(0);
}
TIsvSettlementAttach.java
public class TIsvSettlementAttach implements java.io.Serializable {
// Fields
private String id;
private TIsvSettlement TIsvSettlement;
private String isvproductno;
private String usernum;
private String amount;
private String settleSum;
private String sum;
private Date createtime;
private String isvuserid;
private String productid;
private String unit;
private Double price;
private Long buytimes;
private Double amount2;
private Date begintime;
private Date disabletime;
private String userid;
private String username;
===========================================================================================================================================================
例子2：
String HSQL=" select t.voucherno, t2.settleSum, t3.name FROM TSettlementPaymentRec t , TIsvSettlementAttach t2 , TC001CorpMessage t3 " +
" WHERE t2.TIsvSettlement.settlementid = 'S2011042000066' AND t.TIsvSettlement=t2.TIsvSettlement AND t2.isvuserid=t3.userid";
List ltest=this.findByHSQL(HSQL);
取结果：
ArrayList sList = (ArrayList) result;
Iterator iterator1 = sList.iterator();
while (iterator1.hasNext()) {
Object[] o = (Object[]) iterator1.next();
tBookInfo bookInfo = (tBookInfo) o[0];
BookSelection bookSelect = (BookSelection) o[1];
System.out.println("BookInfo-Title: " + bookInfo.getTitle());
System.out.println("BookSelection-BookSelectionId: " + bookSelect.getId());
}
例子3：
String HSQL=" select t2.settleSum, t3.name,t4.name FROM TIsvSettlementAttach t2 , TC001CorpMessage t3,TCusProduct t4 " +
" WHERE t2.id like '405' AND t2.isvuserid=t3.userid AND t4.productid=t2.productid";
List ltest=this.findByHSQL(HSQL);
int i=0;
例子4,去重复记录：
String HSQL=" select distinct t2.settleSum, t3.name,t4.name FROM TIsvSettlementAttach t2 , TC001CorpMessage t3,TCusProduct t4 " +
" WHERE t2.isvuserid=t3.userid AND t4.productid=t2.productid";
List ltest=this.findByHSQL(HSQL);
例子5,LIKe查询：
String HSQL=" select t2.settleSum, t3.name,t4.name FROM TIsvSettlementAttach t2 , TC001CorpMessage t3,TCusProduct t4 " +
" WHERE t3.name like '%三' AND t2.isvuserid=t3.userid AND t4.productid=t2.productid";
==================================================================================================================
Hibernate 对左右连接查询的支持不完善，需要做配置XML文件和关联关系才行，比较复杂，对于任意表字段的外连接无法支持。
简单的 做法是用SQL语法把外连接翻译成内连接语法，
Oracle SQL1：
select t3.userid,t2.isvuserid,t2.settle_Sum, t3.name from T_Isv_Settlement_Attach t2 , T_C001_Corp_Message t3 where t2.isvuserid(+)=t3.userid;
等于SQL2：
select null as isvuserid,null as settle_Sum ,t3.userid, t3.name
from T_C001_Corp_Message t3 where t3.userid not in (select t2.isvuserid from T_Isv_Settlement_Attach t2 , T_C001_Corp_Message t3 where t2.isvuserid=t3.userid)
union all
select t2.isvuserid,t2.settle_Sum, t3.userid,t3.name from T_Isv_Settlement_Attach t2 , T_C001_Corp_Message t3 where t2.isvuserid=t3.userid;
Hibernate 对 Union不支持。
所以SQL2还必须用两条SQL来做，然后把2个结果集用LIST对象合并list1.addAll(),结果集出来后，还会有排序问题，
就必须自己实现List类中的排序，可以参考这个函数的做法，实现排序类：
import java.util.*;
public class testClass2 {
/**
* @param args
*/
public static void main(String[] args) {
TIsvSettlementAttach tisv1 = new TIsvSettlementAttach();
tisv1.setId("333");
TIsvSettlementAttach tisv2 = new TIsvSettlementAttach();
tisv2.setId("222");
TIsvSettlementAttach tisv3 = new TIsvSettlementAttach();
tisv3.setId("111");
List
list.add(tisv1);
list.add(tisv2);
list.add(tisv3);
System.out.println("排序前的list：");
System.out.println(list);
Collections.sort(list, new Comparator
public int compare(TIsvSettlementAttach o1, TIsvSettlementAttach o2) {
// 取出操作时间
int ret = 0;
try {
ret = (o1.getId()).compareTo(
o2.getId());
} catch (Exception e) {
throw new RuntimeException(e);
}
return ret;
}
});
System.out.println("排序后的list：");
System.out.println(list);
}
}