I have a problem with a many to many relationship. The tables are: ingredient and nutional value. I created a table of relations between the 2 entities, in which there are the external keys of ingredient and nutrional value (which form the compound key) and some attributes.
Class JoinedNutrionalValueIngredient
:
import lombok.Data;
import javax.persistence.*;
import javax.validation.constraints.NotNull;
import java.io.Serializable;
@Entity @Data
public class JoinedNutrionalValueIngredient implements Serializable {
@EmbeddedId
private NutrionalValueIngredientId id;
@ManyToOne(fetch= FetchType.LAZY)
@MapsId("ingredient_id")
private Ingredient ingredient;
@ManyToOne(fetch=FetchType.LAZY)
@MapsId("nutrional_value_id")
private NutrionalValue nutrionalValue;
@NotNull
String matrixUnit;
@NotNull
int value;
@NotNull
String valueType;
}
Class NutrionalValueIngredientId
:
import javax.persistence.*;
import java.io.Serializable;
import java.util.Objects;
@Embeddable
@Getter
@Setter
public class NutrionalValueIngredientId implements Serializable{
@Column(name = "ingredient_id")
private Long ingredient_id;
@Column(name = "nutrional_value_id")
private Long nutrional_value_id;
public NutrionalValueIngredientId() {
}
public NutrionalValueIngredientId(Long ingredient, Long nutrionalValue){
this.ingredient_id=ingredient;
this.nutrional_value_id=nutrionalValue;
}
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass())
return false;
NutrionalValueIngredientId that = (NutrionalValueIngredientId) o;
return Objects.equals(ingredient_id, that.ingredient_id) &&
Objects.equals(nutrional_value_id, that.nutrional_value_id);
}
@Override
public int hashCode() {
return Objects.hash(ingredient_id, nutrional_value_id);
}
}
When I try to insert a new field inside the relationship table I get this error:
{
"timestamp": 1542653896247,
"status": 500,
"error": "Internal Server Error",
"message": "Could not set field value [1] value by reflection : [class com.whateat.reciper.model.NutrionalValueIngredientId.ingredient_id] setter of com.whateat.reciper.model.NutrionalValueIngredientId.ingredient_id; nested exception is org.hibernate.PropertyAccessException: Could not set field value [1] value by reflection : [class com.whateat.reciper.model.NutrionalValueIngredientId.ingredient_id] setter of com.whateat.reciper.model.NutrionalValueIngredientId.ingredient_id",
"path": "/v1/joinedNutrionalValueIngredients"
}
Edit: I added constructor and annotation @Getter
and @Setter
, but I have the same error.
class NutritionalValue
:
@Data
@Entity
public class NutrionalValue implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@NotNull
private String name;
@NotNull
private String unit;
@NotNull
private String source;
@ManyToOne
@NotNull
@JoinColumn(name = "category_id")
private NutrionalValueCategory category;
@OneToMany(mappedBy = "nutrionalValue")
private Set<JoinedNutrionalValueIngredient> joined = new HashSet<JoinedNutrionalValueIngredient>();
}
edit: after Debopam's answer, this error came out.
{
"timestamp": 1542657216244,
"status": 500,
"error": "Internal Server Error",
"message": "null id generated for:class com.whateat.reciper.model.JoinedNutrionalValueIngredient; nested exception is org.hibernate.id.IdentifierGenerationException: null id generated for:class com.whateat.reciper.model.JoinedNutrionalValueIngredient",
"path": "/v1/joinedNutrionalValueIngredients"
}
The set() method of java. lang. reflect. Field is used to set the value of the field represented by this Field object on the specified object argument to the specified new value passed as parameter.
@Entity @Data
public class JoinedNutrionalValueIngredient implements Serializable {
@EmbeddedId
private NutrionalValueIngredientId id = new NutrionalValueIngredientId();
// ... rest of class
}
In the JoinedNutrionalValueIngredient
class the compound id NutrionalValueIngredientId
shall be instansiated.
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