Question

我有以下三个实体EntityA，EntityB和EntityC：

EntityA：

import lombok.*;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

@Entity
@Table(name = "Entity_A")
@Getter
@Setter
@Builder
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode(of = "locationA")
@ToString(of = "locationA")
public class EntityA {
    @Id
    @Column(name = "Name_A", length = 10)
    private String nameA;
    @Column(name = "Loc_A", length = 10)
    private String locationA;
    @ManyToMany(cascade = { CascadeType.MERGE })
    @JoinTable(
            name = "En_A_On_B",
            joinColumns = { @JoinColumn(name = "Name_A") },
            inverseJoinColumns = { @JoinColumn(name = "B_id") }
    )
    private Set<EntityB> bs;
}

实体B：

import lombok.*;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

@Entity
@Table(name = "Entity_B")
@Setter
@Getter
@Builder
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode(of = "locationB")
@ToString(of = "locationB")
public class EntityB {
    @Id
    @GeneratedValue
    @Column(name = "B_id")
    private int id;
    @Column(name = "Loc_B", length = 10)
    private String locationB;
    @ManyToMany(cascade = { CascadeType.MERGE })
    @JoinTable(
            name = "En_C_on_B",
            joinColumns = { @JoinColumn(name = "B_id") },
            inverseJoinColumns = { @JoinColumn(name = "C") }
    )
    private Set<EntityC> cs;
 }

EntityC：

 import lombok.*;

import javax.persistence.*;
import java.util.Set;

@Entity
@Table(name = "Entity_C")
@Getter
@Setter
@Builder
@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode(of = "c")
@ToString(of = "c")
public class EntityC {
    @Id
    @Column(name = "C", length = 20)
    private String c;    
}

要保存的服务类别：

@Service
@Slf4j
public class ServiceClass {
    @Autowired
    private EntityARepository entityARepository;

    private Set<EntityC> cs1 = new HashSet<>(asList(
            EntityC.builder().c("100").build(),
            EntityC.builder().c("10").build()
    ));

    private Set<EntityC> cs2 = new HashSet<>(asList(
            EntityC.builder().c("100").build(),
            EntityC.builder().c("200").build()
    ));

    //METHOD TO SAVE
    public void save() {
        Map<String, Set<EntityC>> map = new HashMap<>();
        map.put("B1", cs1);
        map.put("B2", cs2);

        List<String> bs = asList("B1", "B2");
        EntityA aa = EntityA.builder().nameA("abcd").locationA("mon").build();
        EntityA ab = EntityA.builder().nameA("abcde").locationA("money").build();

        bs.forEach(b -> {
            EntityB entityB = EntityB.builder().locationB("100xxx").build()
            entityB.getCs().addAll(map.get(b));            

            aa.getBs().add(entityB);
            ab.getBs().add(entityB);
        });

        entityARepository.save(aa);
        entityARepository.save(ab);
    }
}

上述代码的执行会引发以下异常

由于：java.lang.IllegalStateException：同一实体[com.xxx.xxx.xxx.xxx.EntityC＃100]的多个表示形式正在被合并。分离：[（c = 100）];分离：[（c = 100）]

注意：我已经在互联网上进行了探索，但没有一个与我的情况相符

任何想法我该如何纠正该问题

Answer 1

问题就在这里：

select location_id, full_name, locationName, item_id, displayname, 
   LOCATION_ON_HAND_COUNT, LOCATION_ON_ORDER_COUNT, 
   LOCATION_QUANTITYBACKORDERED, 
   LOCATION_AVAILABLE_COUNT, LOCATION_REORDER_POINT 
   , ir.W_QtyOrdered, ir.WQty_Shipped, ir.WOnHand, 
   ir.item_no, ir.ItemNo
    from dw_item_location
   left join westrock.InventoryReport IR on 
      dw_item_location.znumber = IR.ItemNo
  where location_id = 2 or location_id = 3

您试图在一个工作单元中保留同一实体的两个版本。想象一下，您输入：

private Set<EntityC> cs1 = new HashSet<>(asList(
        EntityC.builder().c("100").build(), //this entity instance has the same identifier...
        EntityC.builder().c("10").build()
));

private Set<EntityC> cs2 = new HashSet<>(asList(
        EntityC.builder().c("100").build(), //...as this one
        EntityC.builder().c("200").build()
));

在EntityC.builder().c("100").name("A name").build()中：

cs1

在

EntityC.builder().c("100").name("Another name").build()

中

代替。由于两个实体具有相同的cs2（id），Hibernate应该如何知道哪个版本“获胜”？

尝试将c="100"中相同的实例放在两组中，问题应该消失了。

java.lang.IllegalStateException：相同实体[]的多个表示形式正在被合并。分离：[];分离：[]

1 个答案: