DataNucleus Enhancer在LongIdentity上失敗。 （datanucleus-maven-plugin 5.0.2）

Question

我試圖創建復合PK作為作為記錄了許多一對多歸於關系如下位置 ：但是當我使用未明顯增強LongIdentity 。 當前的DataNucleus Enhancer是否與它不兼容？

@PersistenceCapable(identityType = IdentityType.APPLICATION, cacheable = "false", detachable = "true",
    objectIdClass = CompanyProduct.PK.class)
public class CompanyProduct implements Serializable {

private static final long serialVersionUID = -7578808257727591074L;

@PrimaryKey
private Company company; // PK
@PrimaryKey
private Product product; // PK
...

public static class PK implements Serializable {

    private static final long serialVersionUID = -2090216333556951760L;
    public LongIdentity company; // Use same name as CompanyProduct field
    public LongIdentity product; // Use same name as CompanyProduct field

    public PK() {
    }

    public PK(String s) {
        StringTokenizer st = new StringTokenizer(s, "::");
        this.company = new LongIdentity(Company.class, st.nextToken());//
        this.product = new LongIdentity(Product.class, st.nextToken());//
    }

    @Override
    public String toString() {
        return (company.toString() + "::" + product.toString());
    } 
...

產品.java

@PersistenceCapable(identityType = IdentityType.APPLICATION, cacheable = "false", detachable = "true")
public class Product implements Serializable {

private static final long serialVersionUID = 8269335445554701873L;


@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
long id;
@Persistent(mappedBy = "product")
private Set<CompanyProduct> companyProducts = new HashSet<>();
  ...

公司.java

@PersistenceCapable(identityType = IdentityType.APPLICATION, cacheable = "false", detachable = "true")
public class Company implements Serializable {

private static final long serialVersionUID = 6364869685797117033L;
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
//private 
long id;
@Persistent(mappedBy = "company")
private Set<CompanyProduct> companyProducts = new HashSet<>();

我究竟做錯了什么？ datanucleus-maven-plugin版本是5.0.2， datanucleus-core版本是5.1.6。

Answer 1

基於討論和對決定使用哪種身份的案例的試驗，我發現通過在中間類中添加一個字段作為其Application identity （生成的值），可以方便地繼續Application identity 。 有了這些，我不需要手動編寫PK類。 因此，我的代碼如下：

CompanyProduct.java（many_to_many_attributed）

@PersistenceCapable(identityType = IdentityType.APPLICATION, cacheable = "false", detachable = "true")
public class CompanyProduct implements Serializable {

private static final long serialVersionUID = -7578808257727591074L;

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
long id;
@Persistent
private Company company;
@Persistent
private Product product; 

...

公司.java

@PersistenceCapable(identityType = IdentityType.APPLICATION, cacheable = "false", detachable = "true")
public class Company implements Serializable {

private static final long serialVersionUID = 6364869685797117033L;

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
long id;
@Persistent(mappedBy = "company")
private Set<CompanyProduct> companyProducts = new HashSet<>();

...

產品.java

@PersistenceCapable(identityType = IdentityType.APPLICATION, cacheable = "false", detachable = "true")
public class Product implements Serializable {

private static final long serialVersionUID = 8269335445554701873L;

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
long id;
@Persistent(mappedBy = "product")
private Set<CompanyProduct> companyProducts = new HashSet<>();
...

除非有人建議我不要使用“應用程序身份”，否則這就是我現在已經解決的問題。 感謝@Billy和@ DN1