没有criteriaQuery的手动方法
我已经使用此代码来获取包含Thirdparty的结果集，方法是使用左连接和另一个表ThirdPartyHasOwner，它具有两个主键并且本身就是外键。现在，下面的代码检索正确的结果数据集。
Query query = emManager.createQuery("SELECT c FROM ThirdParty c LEFT JOIN ThirdPartyHasOwner b ON b.id.third_party_Id = c.id WHERE b.id.ownerId=1");
List<ThirdParty> thirdParties = query.getResultList();
使用条件构建器和条件查询
但是当使用条件构建器和查询时，结果集会提供错误的数据集。代码如下所示，为了检查上面的手动查询和条件查询是否给出了相同的查询，我添加了属性<property name="eclipselink.logging.level" value="FINE"/>，其中上面的代码没有条件查询，下面的代码带有条件查询，两者都给出了相同的查询。代码和控制台结果如下所示
CriteriaBuilder cb = emManager.getCriteriaBuilder();
CriteriaQuery<ThirdParty> cq = cb.createQuery(ThirdParty.class);
Root<ThirdParty> a = cq.from(ThirdParty.class);
Join<ThirdParty, ThirdPartyHasOwner> b = a.join("thirdPartyHasOwners", JoinType.LEFT);
ParameterExpression<Integer> balance = cb.parameter(Integer.class);
Path<Integer> path = b.get("id").get("ownerId");
cq.where(cb.gt(path, balance));
cq.select(a);
TypedQuery<ThirdParty> queryS = emManager.createQuery(cq);
List<ThirdParty> results = queryS.setParameter(balance, 1).getResultList();
控制台结果（第一个用于条件查询，第二个用于手动方法）
[EL Fine]: sql: 2017-01-04 06:42:44.026--ServerSession(514728045)--Connection(1288428548)--Thread(Thread[http-bio-8080-exec-3,5,main])--SELECT t1.Id, t1.ADDRESS, t1.CONTACTNO, t1.CREATEDDATE, t1.EMAIL, t1.NAME FROM third_party t1 LEFT OUTER JOIN third_party_has_owner t0 ON (t0.THIRD_PARTY_ID = t1.Id) WHERE (t0.owner_id > ?)
bind => [1]
[EL Fine]: sql: 2017-01-04 06:48:26.109--ServerSession(514728045)--Connection(1288428548)--Thread(Thread[http-bio-8080-exec-3,5,main])--SELECT t1.Id, t1.ADDRESS, t1.CONTACTNO, t1.CREATEDDATE, t1.EMAIL, t1.NAME FROM third_party t1 LEFT OUTER JOIN third_party_has_owner t0 ON (t0.THIRD_PARTY_ID = t1.Id) WHERE (t0.owner_id = ?)
bind => [1]
result for both manual and criteria query（结果变量有错误的数据，这是使用条件查询的结果，而第三方变量具有正确的数据集，这是手动方法的结果）
最后但并非最不重要的是我使用的是javax.persistence.persistence-api eclipselink
This is the overview of the Database tables
第三方模特类
/**
* The persistent class for the third_party database table.
*
*/
@Entity
@Table(name="third_party")
@NamedQuery(name="ThirdParty.findAll", query="SELECT t FROM ThirdParty t")
public class ThirdParty implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="Id")
private int id;
private String address;
private String contactNo;
@Temporal(TemporalType.TIMESTAMP)
private Date createdDate;
private String email;
private String name;
//bi-directional many-to-one association to ThirdPartyHasOwner
@OneToMany(mappedBy="thirdParty")
private List<ThirdPartyHasOwner> thirdPartyHasOwners;
//bi-directional many-to-one association to ThirdSeatAllocation
@OneToMany(mappedBy="thirdParty")
private List<ThirdSeatAllocation> thirdSeatAllocations;
public ThirdParty() {
}
public int getId() {
return this.id;
}
public void setId(int id) {
this.id = id;
}
public String getAddress() {
return this.address;
}
public void setAddress(String address) {
this.address = address;
}
public String getContactNo() {
return this.contactNo;
}
public void setContactNo(String contactNo) {
this.contactNo = contactNo;
}
public Date getCreatedDate() {
return this.createdDate;
}
public void setCreatedDate(Date createdDate) {
this.createdDate = createdDate;
}
public String getEmail() {
return this.email;
}
public void setEmail(String email) {
this.email = email;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public List<ThirdPartyHasOwner> getThirdPartyHasOwners() {
return this.thirdPartyHasOwners;
}
public void setThirdPartyHasOwners(List<ThirdPartyHasOwner> thirdPartyHasOwners) {
this.thirdPartyHasOwners = thirdPartyHasOwners;
}
public ThirdPartyHasOwner addThirdPartyHasOwner(ThirdPartyHasOwner thirdPartyHasOwner) {
getThirdPartyHasOwners().add(thirdPartyHasOwner);
thirdPartyHasOwner.setThirdParty(this);
return thirdPartyHasOwner;
}
public ThirdPartyHasOwner removeThirdPartyHasOwner(ThirdPartyHasOwner thirdPartyHasOwner) {
getThirdPartyHasOwners().remove(thirdPartyHasOwner);
thirdPartyHasOwner.setThirdParty(null);
return thirdPartyHasOwner;
}
public List<ThirdSeatAllocation> getThirdSeatAllocations() {
return this.thirdSeatAllocations;
}
public void setThirdSeatAllocations(List<ThirdSeatAllocation> thirdSeatAllocations) {
this.thirdSeatAllocations = thirdSeatAllocations;
}
public ThirdSeatAllocation addThirdSeatAllocation(ThirdSeatAllocation thirdSeatAllocation) {
getThirdSeatAllocations().add(thirdSeatAllocation);
thirdSeatAllocation.setThirdParty(this);
return thirdSeatAllocation;
}
public ThirdSeatAllocation removeThirdSeatAllocation(ThirdSeatAllocation thirdSeatAllocation) {
getThirdSeatAllocations().remove(thirdSeatAllocation);
thirdSeatAllocation.setThirdParty(null);
return thirdSeatAllocation;
}
}
第三方的模特类拥有所有者
/**
* The persistent class for the third_party_has_owner database table.
*
*/
@Entity
@Table(name="third_party_has_owner")
@NamedQuery(name="ThirdPartyHasOwner.findAll", query="SELECT t FROM ThirdPartyHasOwner t")
public class ThirdPartyHasOwner implements Serializable {
private static final long serialVersionUID = 1L;
@EmbeddedId
private ThirdPartyHasOwnerPK id;
@Temporal(TemporalType.DATE)
private Date createdDate;
//bi-directional many-to-one association to Owner
@ManyToOne
private Owner owner;
//bi-directional many-to-one association to ThirdParty
@ManyToOne
@JoinColumn(name="third_party_Id")
private ThirdParty thirdParty;
public ThirdPartyHasOwner() {
}
public ThirdPartyHasOwnerPK getId() {
return this.id;
}
public void setId(ThirdPartyHasOwnerPK id) {
this.id = id;
}
public Date getCreatedDate() {
return this.createdDate;
}
public void setCreatedDate(Date createdDate) {
this.createdDate = createdDate;
}
public Owner getOwner() {
return this.owner;
}
public void setOwner(Owner owner) {
this.owner = owner;
}
public ThirdParty getThirdParty() {
return this.thirdParty;
}
public void setThirdParty(ThirdParty thirdParty) {
this.thirdParty = thirdParty;
}
}
那么我对条件查询做了什么错误还是一些奇怪的错误？
答案 0 :(得分：0)
虽然日志还不错，但我还是使用了一种不同的方法来提供不同的数据集。
代码之前
CriteriaBuilder cb = emManager.getCriteriaBuilder();
CriteriaQuery<ThirdParty> cq = cb.createQuery(ThirdParty.class);
Root<ThirdParty> a = cq.from(ThirdParty.class);
Join<ThirdParty, ThirdPartyHasOwner> b = a.join("thirdPartyHasOwners", JoinType.LEFT);
ParameterExpression<Integer> balance = cb.parameter(Integer.class);
Path<Integer> path = b.get("id").get("ownerId");
cq.where(cb.gt(path, balance));
cq.select(a);
TypedQuery<ThirdParty> queryS = emManager.createQuery(cq);
List<ThirdParty> results = queryS.setParameter(balance, 1).getResultList();
代码后
CriteriaBuilder cb = emManager.getCriteriaBuilder();
CriteriaQuery<ThirdParty> cq = cb.createQuery(ThirdParty.class);
Root<ThirdParty> a = cq.from(ThirdParty.class);
Join<ThirdParty, ThirdPartyHasOwner> b = a.join("thirdPartyHasOwners", JoinType.LEFT);
ParameterExpression<Integer> balance = cb.parameter(Integer.class);
cq.where(cb.equal( b.get("id").get("ownerId"),balance));
cq.select(a);
TypedQuery<ThirdParty> queryS = emManager.createQuery(cq);
List<ThirdParty> results = queryS.setParameter(balance, 1).getResultList();
正在更改的代码为cq.where(cb.gt(path, balance));到cq.where(cb.equal( b.get("id").get("ownerId"),balance));，因为此处使用的条件构建器等于Where b.owner_id = balance balance是参数