我有这个SQL语句:
select c.*
from tableA a
inner join tableB b on a.id = b.a_id
inner join tableC c on b.id = c.b_id
我的标准是:
Criteria criteria = session.createCriteria(tableA.class, "a")
.createAlias("a.b", "b")
.createAlias("b.c", "c");
如何选择符合条件的tableC?
之类的东西 -
List<tableC> listC = criteria.list()
我尝试添加投影.setProjection(Property.forName("c"))
但是我收到了以下错误:
org.hibernate.QueryException: could not resolve property: c of: ...xx.xx.tableA
at org.hibernate.persister.entity.AbstractPropertyMapping.propertyException(AbstractPropertyMapping.java:81)
at org.hibernate.persister.entity.AbstractPropertyMapping.toType(AbstractPropertyMapping.java:75)
at org.hibernate.persister.entity.AbstractEntityPersister.toType(AbstractEntityPersister.java:1465)
这是我的课程:
CnTermsGroup类
@Entity
@Table(name="CN_TERMS_GROUP")
public class CnTermsGroup extends implements Serializable {
private static final long serialVersionUID = 1145853863134597537L;
@Id
@Column(name="CN_TERMS_GROUP_ID")
private long cnTermsGroupId;
@Column(name="CN_TERMS_GROUP_NAME")
private String cnTermsGroupName;
@OneToMany(mappedBy="cnTermsGroup", cascade=CascadeType.ALL, orphanRemoval=true)
@Fetch(FetchMode.SUBSELECT)
private List<CnTermsCounted> cnTermsCounteds;
public CnTermsGroup() {
}
public long getCnTermsGroupId() {
return this.cnTermsGroupId;
}
public void setCnTermsGroupId(long cnTermsGroupId) {
this.cnTermsGroupId = cnTermsGroupId;
}
public String getCnTermsGroupName() {
return this.cnTermsGroupName;
}
public void setCnTermsGroupName(String cnTermsGroupName) {
this.cnTermsGroupName = cnTermsGroupName == null ? "" : cnTermsGroupName;
}
public List<CnTermsCounted> getCnTermsCounteds() {
return this.cnTermsCounteds;
}
public void setCnTermsCounteds(List<CnTermsCounted> cnTermsCounteds) {
this.cnTermsCounteds = cnTermsCounteds;
}
@Override
public Object getId(){
return cnTermsGroupId;
}
}
CnTermsCounted类
@Entity
@Table(name="CN_TERMS_COUNTED")
public class CnTermsCounted extends BaseModelImp implements Serializable{
private static final long serialVersionUID = -8486592249097766983L;
@Id
@Column(name="CN_TERMS_COUNTED_ID")
private long cnTermsCountedId;
@ManyToOne(fetch = FetchType.LAZY)
@Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
@JoinColumn(name="CN_TERMS_GROUP_ID")
private CnTermsGroup cnTermsGroup;
@OneToMany(mappedBy = "cnTermsCounted", cascade=CascadeType.ALL, orphanRemoval=true)
@Fetch(FetchMode.SUBSELECT)
private Set<CnTermsRun> cnTermsRuns;
public CnTermsCounted() {
}
public long getCnTermsCountedId() {
return this.cnTermsCountedId;
}
public void setCnTermsCountedId(long cnTermsCountedId) {
this.cnTermsCountedId = cnTermsCountedId;
}
public CnTermsGroup getCnTermsGroup() {
return this.cnTermsGroup;
}
public void setCnTermsGroup(CnTermsGroup cnTermsGroup) {
this.cnTermsGroup = cnTermsGroup;
}
public Set<CnTermsRun> getCnTermsRuns() {
return this.cnTermsRuns;
}
public void setCnTermsRuns(Set<CnTermsRun> cnTermsRuns) {
this.cnTermsRuns = cnTermsRuns;
}
@Override
public Object getId() {
return cnTermsCountedId;
}
}
和CnTermsRun类
@Entity
@Table(name="CN_TERMS_RUN")
public class CnTermsRun extends BaseModelImp {
private static final long serialVersionUID = -9042920700902106238L;
@Id
@Column(name="CN_TERMS_RUN_ID")
private long cnTermsRunId;
@ManyToOne
@JoinColumn(name="CN_TERMS_COUNTED_ID")
private CnTermsCounted cnTermsCounted;
public CnTermsRun() {
}
public long getCnTermsRunId() {
return this.cnTermsRunId;
}
public void setCnTermsRunId(long cnTermsRunId) {
this.cnTermsRunId = cnTermsRunId;
}
public CnTermsCounted getCnTermsCounted() {
return this.cnTermsCounted;
}
public void setCnTermsCounted(CnTermsCounted cnTermsCounted) {
this.cnTermsCounted = cnTermsCounted;
}
/* (non-Javadoc)
* @see com.sintecmedia.onair.model.imp.BaseModelImp#getId()
*/
@Override
public Object getId() {
return cnTermsRunId;
}
}
和标准:
Criteria criteria = session.createCriteria(CnTermsGroup.class, "cnTermsGroup")
.createAlias("cnTermsGroup.cnTermsCounteds", "cnTermsCounted")
.createCriteria("cnTermsCounted.cnTermsRuns")
.setResultTransformer(Transformers.aliasToBean(CnTermsRun.class));
答案 0 :(得分:1)
我可以想到两种方法。
第一种方法是使用Criteria.ALIAS_TO_ENTITY_MAP
,如下所示
Criteria criteria = session.createCriteria(CnTermsGroup.class, "cnTermsGroup")
.createAlias("cnTermsGroup.cnTermsCounteds", "cnTermsCounted")
.createAlias("cnTermsCounted.cnTermsRuns", "cnTermsRuns")
.setResultTransformer(Criteria.ALIAS_TO_ENTITY_MAP);
这会返回List<Map<String, Object>>
。我们可以使用alias name
收集所需的实体,如下所示,例如:收集CnTermsRun
个实体:
List<CnTermsRun> subEntities = new ArrayList<>();
List<Map<String, Object>> objects = criteria.list();
for (Map<String, Object> record : objects) {
subEntities.add((CnTermsRun)record.get("cnTermsRuns"));
}
第二种方法是使用Transformers.aliasToBean(...)
,如下所示
这会直接返回List<CnTermsRun>
,但需要添加新的constructor
以及默认构造函数:
public CnTermsRun(long cnTermsRunId, CnTermsCounted cnTermsCounted) {
this.cnTermsRunId = cnTermsRunId;
this.cnTermsCounted = cnTermsCounted;
}
以下标准:
Criteria criteria = session.createCriteria(CnTermsGroup.class, "cnTermsGroup")
.createAlias("cnTermsGroup.cnTermsCounteds", "cnTermsCounted")
.createAlias("cnTermsCounted.cnTermsRuns", "cnTermsRuns")
.setProjection(Projections.projectionList().add(Projections.alias(Projections.property("cnTermsRuns.id"), "cnTermsRunId")).add(Projections.alias(Projections.property("cnTermsRuns.cnTermsCounted"), "cnTermsCounted")))
.setResultTransformer(Transformers.aliasToBean(CnTermsRun.class));
List<CnTermsRun> subEntities = criteria.list();