Java – select query using composite primary key

In the spring MVC app using hibernate and JPA, I recently used the @ embeddable class to switch to the composite primary key Therefore, I need to update the JPA query that returns a given object based on its unique ID The following is the JPA code that worked in the past, but no results will be returned:

@SuppressWarnings("unchecked")
public Concept findConceptById(BigInteger id) {
    Query query = this.em.createQuery("SELECT conc FROM Concept conc WHERE conc.id =:cid");
    query.setParameter("cid",id);
    return (Concept) query.getSingleResult();
}@H_419_12@ 
 
如何更改上面的查询,以便返回具有给定id的最新有效时间的Concept？请注意,id和effectiveTime是ConceptPK复合主键的两个属性,因此id和effectiveTime的属性定义和getter以及setter在ConceptPK类中,而不在Concept类中.
 
 
上面抛出的错误是：
 
 
 
 
Caused by: java.lang.IllegalArgumentException:  
Parameter value [786787679] did not match expected type [myapp.ConceptPK]@H_419_12@ 
 
这是现在在Concept类中定义主键的方式：
 
 
 
 
private ConceptPK conceptPK;@H_419_12@ 
 
这是ConceptPK类的代码：
 
 
 
 
@Embeddable
class ConceptPK implements Serializable {

    @Column(name="id",nullable=false)
    protected BigInteger id;

    @Column(name="effectiveTime",nullable=false)
    @Type(type="org.jadira.usertype.dateandtime.joda.PersistentDateTime")
    private DateTime effectiveTime;

    public ConceptPK() {}
    public ConceptPK(BigInteger bint,DateTime dt) {
        this.id = bint;
        this.effectiveTime = dt;
    }

    /** getters and setters **/
    public DateTime getEffectiveTime(){return effectiveTime;}
    public void setEffectiveTime(DateTime ad){effectiveTime=ad;}

    public void setId(BigInteger id) {this.id = id;}
    public BigInteger getId() {return id;}

    @Override
    public boolean equals(Object obj) { 
        if (this == obj) return true;
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        final ConceptPK other = (ConceptPK) obj;
        if (effectiveTime == null) {
            if (other.effectiveTime != null) return false;
            } else if (!effectiveTime.equals(other.effectiveTime)) return false;
        if (id == null) {
            if (other.id != null) return false;
        } else if (!id.equals(other.id)) return false;
        return true;
    }

    @Override
    public int hashCode() { 
        int hash = 3;
        hash = 53 * hash + ((effectiveTime == null) ? 0 : effectiveTime.hashCode());
        hash = 53 * hash + ((id == null) ? 0 : id.hashCode());
        return hash;
    }
}@H_419_12@

Solution
To use parts of a composite primary key in a JPA query, you must resolve them with their variable names:
public Concept findConceptById(BigInteger id) {
    Query query = this.em.createQuery("SELECT conc FROM Concept conc WHERE conc.conceptPK.id =:cid order by conc.conceptPK.effectiveTime desc");
    query.setParameter("cid",id);
    return (Concept) query.getSingleResult();
}@H_419_12@ 
 
我使用Concept作为实体名称,假设具有@Entity注释的类也被命名为Concept.
 
 
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