使用Spring data JPA访问数据时，在两个表上创建空列

Question

我是Spring Data、JPA和Hibernate的新手。通过查看不同的示例，我为一个实体上的CRUD操作构建了一个工作模型，在连接两个表以使用AF_ID从另一个表（外键）提取AF_NAME时遇到了麻烦。创建一个null列，列的名称是，当访问时，返回null。请检查我是否遵循preocedure进行联接，并向我指出任何教程。我遵循了这个解决方案，但仍然没有进展。

@Entity
@Configuration
@EnableAutoConfiguration
@Table(name = "AFF_CONFIG")
public class AFF_CONFIG implements Serializable {

@Id
@Column(name = "AFF_CONFIG_ID")
private String AFF_CONFIG_ID;

@Column(name = "AFF_ID")
private String AFF_ID;

@Column(name = "CH_ID")
private String CH_ID;

@Column(name = "M_ID")
private Long M_ID;

@Column(name = "KEY")
private String KEY;

@Column(name = "VALUE")
private String VALUE;

@Column(name = "SYSTEM")
private String SYSTEM;

private AFF aff;

@LazyCollection(LazyCollectionOption.TRUE)
@ManyToOne
@JoinColumn(name = "AFF_ID")
public AFF getAff() {
    return aff;
}

public void setAffiliate(AFF aff) {
    this.aff = aff;
}

public String getAFF_CONFIG_ID() {
    return AFF_CONFIG_ID;
}

public void setAFF_CONFIG_ID(String aFF_CONFIG_ID) {
    AFF_CONFIG_ID = aFF_CONFIG_ID;
}

public String getAFF_ID() {
    return AFF_ID;
}

public void setAFF_ID(String aFF_ID) {
    AFF_ID = AFF_ID;
}

public String getCH_ID() {
    return CH_ID;
}

public void setCHANNEL_ID(String cH_ID) {
    CH_ID = cH_ID;
}

public Long getM_ID() {
    return M_ID;
}

public void setM_ID(Long m_ID) {
    M_ID = m_ID;
}

public String getKEY() {
    return KEY;
}

public void setKEY(String kEY) {
    KEY = kEY;
}

public String getVALUE() {
    return VALUE;
}

public void setVALUE(String vALUE) {
    VALUE = vALUE;
}

public String getSYSTEM() {
    return SYSTEM;
}

public void setSYSTEM(String sYSTEM) {
    SYSTEM = sYSTEM;
}

第二个实体是：

@Entity
@Table(name = "AFF")
public class AFF implements Serializable {

@Column(name = "AFF_NAME")
private String AFF_NAME;

@Column(name = "AFF_CODE")
private String AFF_CODE;

@Id
@Column(name = "AFF_ID")
private String AFF_ID;

private Set<AFF_CONFIG> someAff = new HashSet<AFF_CONFIG>();

@LazyCollection(LazyCollectionOption.TRUE)
@OneToMany(cascade = CascadeType.ALL, mappedBy = "aff")

public Set<AFF_CONFIG> getSomeAff() {
    return someAff;
}

public void setSomeAff(Set<AFF_CONFIG> someAff) {
    this.someAff = someAff;
}

public String getAFF_ID() {
    return AFF_ID;
}

public void setAFF_ID(String aFF_ID) {
    AFF_ID = aFF_ID;
}

public String getAFF_NAME() {
    return AFF_NAME;
}

public void setAFF_NAME(String aFF_NAME) {
    AFF_NAME = aFF_NAME;
}

public String getAFF_CODE() {
    return AFF_CODE;
}

public void setAFF_CODE(String aFF_CODE) {
    AFF_CODE = aFF_CODE;
}

@Repository
public interface MarketRepository extends       CrudRepository<AFF_CONFIG,String> {

Page<AFF_CONFIG> findAll(Pageable pageable);

 @Query("Select a,b from AFF_CONFIG a, AFF b where     a.AFF_ID = b.AFF_ID" )
public List<AFF_CONFIG> getAffData();
} 

Answer 1

我在主管的帮助下解决了这个问题。看来我们必须遵循类和变量的命名规范。还有一个修正是移除集合类型对象，并将其更改为just object（在aff类中移除设置）。我将在稍后发布修正后的内容，以进行比较和对比。