Spring Data Rest 持久化注解

Question

我正在学习 Spring-Data-REST 并且遇到了涉及我的注释的障碍。目前我有以下架构：create table user(    ID int NOT NULL auto_increment,     NAME VARCHAR(60) NOT NULL,    PASS VARCHAR(20) NOT NULL,    primary key (ID));create table recipe(    ID int NOT NULL auto_increment,    NAME varchar(60) NOT NULL,     USER_ID int NOT NULL,    primary key (ID),    FOREIGN KEY (USER_ID) REFERENCES user(ID) ON DELETE CASCADE);create table ingredient(    ID int not null auto_increment,    NAME varchar(60) not null,    primary key(ID));create table ingredientsList (    ID int NOT NULL auto_increment,    NAME varchar(60) NOT NULL,    RECIPE_ID int not null,    INGREDIENT_ID int not null,    QUANTITY int not null,    primary key (ID),    foreign key (RECIPE_ID) REFERENCES recipe(ID) on delete cascade,    foreign key (INGREDIENT_ID) references ingredient(ID) on delete cascade);create table direction(    ID int NOT NULL auto_increment,    NAME varchar(60) NOT NULL,    RECIPE_ID int not null,    STEP int not null,    DESCRIPTION varchar(256),    primary key (ID),    foreign key (RECIPE_ID) REFERENCES recipe(ID) on delete cascade);我的 Spring Data REST API 中表示了每个表，除了一个表，即成分列表表。这是我当前的实现，当我运行 .\mvn clean install 时无法正常工作：import java.util.Objects;import java.util.Set;import javax.persistence.Column;import javax.persistence.CascadeType;import javax.persistence.Entity;import javax.persistence.FetchType;import javax.persistence.JoinColumn;import javax.persistence.ManyToOne;import javax.persistence.OneToMany;@Entitypublic class IngredientsList extends AbstractEntity {    @ManyToOne(fetch = FetchType.EAGER)    @JoinColumn(nullable=false)    private Recipe recipe;    @OneToMany(mappedBy = "ingredientsList", fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)    private Set<Ingredient> ingredients;    @Column(nullable = false)    private Long quantity;    public Recipe getRecipe() {        return recipe;    }    public void setRecipe(Recipe recipe){        this.recipe = recipe;    }

Answer 1

您@OneToMany对IngredientsList类的注释暗示类中应该有一个ingredientsList字段Ingredient，而实际上没有。在您的架构中，您INGREDIENT_ID的ingredientsList表中有一个字段，这意味着 anIngredientsList只能有一个Ingredient.

我认为你的意思是IngredientsList有很多Ingredient孩子，这意味着ingredient表应该有一个INGREDIENT_LIST_ID字段作为ingredientsList表的外键，并且Ingredients类应该有一个ingredientsList字段。该INGREDIENT_ID字段应该从ingredientsList表中删除。

如果一个IngredientsList应该只有一个Ingredient，那么改变

@OneToMany(mappedBy = "ingredientsList", fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)

private Set<Ingredient> ingredients;

到

@ManyToOne

@JoinColumn("ingredient_id")

private Ingredient ingredient

根据需要添加cascade和orphanRemoval。@ManyToOne默认情况下，A应该急切地获取连接的数据。