[英]java.lang.IllegalStateException: Multiple representations of the same entity with @ManyToMany 3 entities
[英]java.lang.IllegalStateException: Multiple representations of the same entity [] are being merged. Detached: []; Detached: []
我有三個實體 EntityA、EntityB 和 EntityC,如下所示:
實體A:
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;
}
實體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;
}
實體C:
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;
}
要保存的服務等級:
@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);
}
}
執行上述代碼拋出以下異常
引起:java.lang.IllegalStateException:正在合並同一實體 [com.xxx.xxx.xxx.xxx.EntityC#100] 的多個表示。 分離:[(c=100)]; 分離:[(c=100)]
注意:我已經在互聯網上進行了探索,但沒有一個與我的場景相符
知道我該如何解決這個問題
問題就在這里:
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()
));
您正在嘗試在單個工作單元中保留同一實體的兩個版本。 想象一下你把:
EntityC.builder().c("100").name("A name").build()
在cs1
和:
EntityC.builder().c("100").name("Another name").build()
在cs2
。 由於兩個實體具有相同的id
( c="100"
),Hibernate 如何知道哪個版本“獲勝”?
嘗試在兩個集合中放置相同的EntityC
實例,問題應該會消失。
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