无法通过反射设置字段值 [英] Could not set field value by reflection

问题描述

我与多对多关系有问题.这些表是:成分和营养价值.我创建了两个实体之间的关系表，其中有成分和营养价值的外键(形成复合键)以及一些属性.

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;
}

类 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);
    }
}

当我尝试在关系表中插入新字段时，出现此错误:

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"
}

我添加了构造函数和注释 @Getter 和 @Setter ，但是我有相同的错误.

I added constructor and annotation @Getter and @Setter, but I have the same error.

类 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>();

}

在Debopam回答后，出现了此错误.

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"
}

推荐答案

按如下所示更改变量名称

Change the variable Names as below

长Ingredient_id到Long Ingredientidnutrional_value_id到nutrionalvalueid

Long ingredient_id to Long ingredientid nutrional_value_id to nutrionalvalueid

示例

  @Column(name = "ingredient_id")
  Long ingredient_id;

到

@Column(name = "ingredient_id")
Long ingredientid;

然后为所有字段生成getter设置程序.Hibernate无法设置字段，因为没有公共获取者/设置者.

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