我正在将Spring Data与CrudRepository
一起使用。我正在尝试将“级联父项”保存到子项中,并且给Hibernate合并子项实体的可能性,但出现错误a different object with the same identifier value was already associated with the session
。当他坚持拥有两个子实体(RecipeIngredients
)的两个父实体时,可能会发生这种情况。我正在尝试覆盖equals和hashcode以仅关注id
和name
,但没有任何变化。 Recipe
对象相同,但List<RecipeIgredients>
不同。关于如何解决的任何想法?
示例:
这是我现有的对象:
{
"id": 100,
"name": "salat",
"ingredients": [
{
"ingredient": {
"id": 100,
"name": "banana"
},
"count": 2
},
{
"ingredient": {
"id": 1,
"name": "eggs"
},
"count": 1
}
]
}
并且我想将其更新为以下一种(删除一种成分):
{
"id": 100,
"name": "salat",
"ingredients": [
{
"ingredient": {
"id": 100,
"name": "bannana"
},
"count": 2
}
]
}
父母:
@Entity
@Data
public class Recipe {
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "recipe_generator")
@SequenceGenerator(name="recipe_generator", sequenceName = "recipe_seq")
@Column(name = "id", nullable = false)
private Long id;
@NaturalId
@Column
private String name;
@OneToMany(mappedBy = "recipe", cascade = CascadeType.ALL, orphanRemoval = true)
private List<RecipeIngredients> ingredients;
}
[儿童在中间表中
@Entity
@Data
public class RecipeIngredients implements Serializable {
@EmbeddedId
private RecipeIngredientsId recipeIngredientsId;
@ManyToOne(fetch = FetchType.LAZY)
@MapsId("recipeId")
private Recipe recipe;
@ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
@MapsId("ingredientId")
private Ingredient ingredient;
@Column
private Integer count;
public RecipeIngredients(Recipe recipe, Ingredient ingredient) {
this.recipe = recipe;
this.ingredient = ingredient;
this.recipeIngredientsId = new RecipeIngredientsId(recipe.getId(), ingredient.getId());
}
}
儿童
@Entity
@Data
public class Ingredient {
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "ingredient_generator")
@SequenceGenerator(name="ingredient_generator", sequenceName = "ingredient_seq")
@Column(name = "id", updatable = false, nullable = true)
private Long id;
@NaturalId
@Column(unique = true)
private String name;
}
package com.yoav.todolist.models;
import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;
@Entity
@Table(name = "accounts")
public class Account {
@Id
@Column(name = "id")
@GeneratedValue(strategy= GenerationType.IDENTITY)
private int id;
@Column(name = "username")
private String username;
@Column(name = "password")
private String password;
@OneToMany(
mappedBy = "account",
orphanRemoval = true,
cascade = CascadeType.ALL
)
private List<Task> tasks = new ArrayList<>();
public Account(String username, String password) {
this.username = username;
this.password = password;
}
public Account() {
}
public void removeTask(Task task) {
tasks.remove(task);
task.setAccount(null);
}
public void addTask(Task task) {
tasks.add(task);
task.setAccount(this);
}
public List<Task> getTasks() {
return tasks;
}
public void setTasks(List<Task> tasks) {
this.tasks.forEach(i -> i.setAccount(null));
this.tasks.clear();
tasks.forEach(i -> {
i.setAccount(this);
addTask(i);
});
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public boolean equals(Object account) {
return ((Account)account).getUsername().equals(this.username);
}
@Override
public String toString() {
return "Account{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
孩子:
package com.yoav.todolist.models;
import com.fasterxml.jackson.annotation.JsonIgnore;
import javax.persistence.*;
import java.util.Date;
@Entity
@Table(name = "tasks")
public class Task {
@Id
@Column(name = "id")
@GeneratedValue(strategy= GenerationType.IDENTITY)
private int id;
@Column(name = "task")
private String task;
@ManyToOne(fetch = FetchType.LAZY)
@JsonIgnore
private Account account;
@Temporal(TemporalType.DATE)
@Column(name = "date_of_creation_task")
private Date date;
public Task(String task) {
this.date = new Date();
this.task = task;
}
public Task() {
this.date = new Date();
}
public Account getAccount() {
return account;
}
public void setAccount(Account account) {
this.account = account;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTask() {
return task;
}
public void setTask(String task) {
this.task = task;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
@Override
public boolean equals(Object task) {
return ((Task)task).getId() == this.id;
}
@Override
public String toString() {
return "Task{" +
"id=" + id +
", task='" + task + '\'' +
'}';
}
@Override
public int hashCode() {
return 31;
}
}
就我而言,我只需要获取例如accountSerice.getById(1);
的实体,然后就我而言,我就需要做account.setTasks(tasks); // tasks is just list of the childs @see the setTasks() at the account(parent) entity