如何使用带有“从方法名创建查询”策略的Spring数据JPA来实现这两个简单查询？

Question

I am pretty new in Spring Data and I have to write what in the official documentation seems to be called Query creation from method names , here the reference: https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#repositories.query-methods.query-creation

As you can see in the previous example show the creation of a query by the definition of a method name, for example:

List<Person> findByEmailAddressAndLastname(EmailAddress emailAddress, String lastname);

that I think return a list of Person object that have a specific email affress and a specific lastname.

So I am trying to do the same thing in my project that use Hibernate as JPA provider.

In my project I have this Twb1012Regione entity class that map the anagrafiche.TWB1012_REGIONE on the database:

@Entity
@Table(name="anagrafiche.TWB1012_REGIONE")
@NamedQuery(name="Twb1012Regione.findAll", query="SELECT t FROM Twb1012Regione t")
public class Twb1012Regione implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @Column(name="COD_REG")
    private String codReg;

    @Column(name="COD_ARE_GEO")
    private String codAreGeo;

    @Column(name="COD_CIT")
    private String codCit;

    @Column(name="COD_IST")
    private int codIst;

    @Column(name="COD_PGM_ULT_MOV")
    private String codPgmUltMov;

    @Column(name="COD_UTE_ULT_MOV")
    private String codUteUltMov;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name="DAT_ORA_ULT_MOV")
    private Date datOraUltMov;

    @Column(name="DES_REG")
    private String desReg;

    //bi-directional many-to-one association to Tpg1029Provnuoist
    @OneToMany(mappedBy="twb1012Regione")
    private List<Tpg1029Provnuoist> tpg1029Provnuoists;

    //bi-directional many-to-one association to Twb1013Provincia
    @OneToMany(mappedBy="twb1012Regione")
    private List<Twb1013Provincia> twb1013Provincias;

    public Twb1012Regione() {
    }

    public String getCodReg() {
        return this.codReg;
    }

    public void setCodReg(String codReg) {
        this.codReg = codReg;
    }

    public String getCodAreGeo() {
        return this.codAreGeo;
    }

    public void setCodAreGeo(String codAreGeo) {
        this.codAreGeo = codAreGeo;
    }

    public String getCodCit() {
        return this.codCit;
    }

    public void setCodCit(String codCit) {
        this.codCit = codCit;
    }

    public int getCodIst() {
        return this.codIst;
    }

    public void setCodIst(int codIst) {
        this.codIst = codIst;
    }

    public String getCodPgmUltMov() {
        return this.codPgmUltMov;
    }

    public void setCodPgmUltMov(String codPgmUltMov) {
        this.codPgmUltMov = codPgmUltMov;
    }

    public String getCodUteUltMov() {
        return this.codUteUltMov;
    }

    public void setCodUteUltMov(String codUteUltMov) {
        this.codUteUltMov = codUteUltMov;
    }

    public Date getDatOraUltMov() {
        return this.datOraUltMov;
    }

    public void setDatOraUltMov(Date datOraUltMov) {
        this.datOraUltMov = datOraUltMov;
    }

    public String getDesReg() {
        return this.desReg;
    }

    public void setDesReg(String desReg) {
        this.desReg = desReg;
    }

    public List<Tpg1029Provnuoist> getTpg1029Provnuoists() {
        return this.tpg1029Provnuoists;
    }

    public void setTpg1029Provnuoists(List<Tpg1029Provnuoist> tpg1029Provnuoists) {
        this.tpg1029Provnuoists = tpg1029Provnuoists;
    }

    public Tpg1029Provnuoist addTpg1029Provnuoist(Tpg1029Provnuoist tpg1029Provnuoist) {
        getTpg1029Provnuoists().add(tpg1029Provnuoist);
        tpg1029Provnuoist.setTwb1012Regione(this);

        return tpg1029Provnuoist;
    }

    public Tpg1029Provnuoist removeTpg1029Provnuoist(Tpg1029Provnuoist tpg1029Provnuoist) {
        getTpg1029Provnuoists().remove(tpg1029Provnuoist);
        tpg1029Provnuoist.setTwb1012Regione(null);

        return tpg1029Provnuoist;
    }

    public List<Twb1013Provincia> getTwb1013Provincias() {
        return this.twb1013Provincias;
    }

    public void setTwb1013Provincias(List<Twb1013Provincia> twb1013Provincias) {
        this.twb1013Provincias = twb1013Provincias;
    }

    public Twb1013Provincia addTwb1013Provincia(Twb1013Provincia twb1013Provincia) {
        getTwb1013Provincias().add(twb1013Provincia);
        twb1013Provincia.setTwb1012Regione(this);

        return twb1013Provincia;
    }

    public Twb1013Provincia removeTwb1013Provincia(Twb1013Provincia twb1013Provincia) {
        getTwb1013Provincias().remove(twb1013Provincia);
        twb1013Provincia.setTwb1012Regione(null);

        return twb1013Provincia;
    }

}

So, into my project I have defined a Twb1012RegioneRepository interface that is my repository class defined on the previous Twb1012Regione entity class:

@RepositoryDefinition(domainClass=Twb1012Regione.class, idClass=String.class)
public interface Twb1012RegioneRepository extends JpaRepository<Twb1012Regione, String> {

    // I have to implement it



}

Now my problem is that I want to create 2 methods (that implement 2 queries by method name as described by the previous tutorial) that perform the following tasks:

1) Return the list of all the Twb1012Regione representing all the record of the TWB1012_REGIONE table on the DB.

2) Given a specific id (the value of the String codReg field, PK of the Twb1012Regione class) I want to obtain the Twb1012Regione object associated to this record.

How can I implement these queries? I have some difficulties to do it

Tnx

Answer 1

You don't need to implement the methods. The Spring Data Repository API will construct query for you as the JpaRepository already has following methods:

• List findAll(Iterable ids)

• T getOne(ID id)

That's the whole point with the Spring Data Repository - To reduce the boiler plate code that you write.