Failed to convert from type [java.lang.String] to type [java.lang.Long] for Spring JPA?

Question

I have a problem about implementing two entities named for Country and State in Spring JPA.

I wrote a code to pose Country and State entities shown below.

Country Entity

@Entity
@Table(name="COUNTRY",catalog ="SPRINGANGULAR")
@Data
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode(of = {"id","code","countryName"}, exclude = "states")
public class Country {

    @Id
    @SequenceGenerator(name="COUNTRY_SEQ", sequenceName="COUNTRY_SEQ", allocationSize=1)
    @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="COUNTRY_SEQ")
    @Column(name="ID", nullable = false)
    private long id;
    
    @Column(name="CODE")
    private String code;
    
    @Column(name="COUNTRY_NAME")
    private String countryName;
    
    @OneToMany(fetch=FetchType.LAZY,mappedBy="country",
            cascade= CascadeType.ALL)
    private Set<State> states = new HashSet<State>();

    public Country(String code, String countryName) {
        super();
        this.code = code;
        this.countryName = countryName;
    }
    
}

State Entity

@Entity
@Table(name="STATE",catalog ="SPRINGANGULAR")
@Data
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode(of = {"id", "stateName"})
public class State {

    @Id
    @SequenceGenerator(name="STATE_SEQ", sequenceName="STATE_SEQ", allocationSize=1)
    @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="STATE_SEQ")
    @Column(name="ID", nullable = false)
    private long id;
    
    @Column(name="STATE_NAME")
    private String stateName;
    
    @ManyToOne(fetch=FetchType.LAZY,cascade= CascadeType.ALL)
    @JoinColumn(name = "COUNTRY_ID", nullable = false)
    private Country country;

    public State(String stateName, Country country) {
        super();
        this.stateName = stateName;
        this.country = country;
    }
    
}

Then I create a State Reporistory to get states by country code.

@CrossOrigin("http://localhost:4200")
@RepositoryRestResource(collectionResourceRel = "states", path = "states")
public interface StateRepository extends JpaRepository<State, Long>{

    @Query("SELECT s FROM State s \n" + 
           "LEFT JOIN Country c ON c.id = c.id \n" + 
           "WHERE c.code = :code \n" + 
           "ORDER BY s.id ASC")
    List<State> findByCountryCode(@RequestParam("code") String code);
}

Then I write a connection url in Postman to check if it works.

http://localhost:8080/api/states/findByCountryCode?code=BR

It throws an error

Failed to convert from type [java.lang.String] to type [java.lang.Long] for value 'findByCountryCode'; nested exception is java.lang.NumberFormatException: For input string: "findByCountryCode"

How can I fix the issue?

Answer 1

The solution is shown below.

I wrongly use this url http://localhost:8080/api/states/findByCountryCode?code=BR

Convert url

http://localhost:8080/api/states/findByCountryCode?code=BR`

to

http://localhost:8080/api/states?code=BR