Building several one-to-many relationships - spring

It implements the model as seen below:
I implement three classes of models:
#Entity
public class Home implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#OneToMany(mappedBy = "home")
private Set<UserHome> userHomes;
}
#Entity
public class UserHome implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#ManyToOne
#JoinColumn(name = "home_id")
private Home home;
#OneToMany(mappedBy = "userhome")
private Set<Key> keys;
}
#Entity
public class Key implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#ManyToOne
#JoinColumn(name = "userhome_id")
private UserHome userHome;
}
When you try to compile it gets an error:
Invocation of init method failed; nested exception is org.hibernate.AnnotationException: mappedBy reference an unknown target entity property: com.example.homeUser.Key.userhome in com.example.homeUser.UserHome.keys
I do not know what's wrong with my code?

There is a typo in your code, the lowercase h in userhome:
#OneToMany(mappedBy = "userhome")
private Set<Key> keys;
Should be (uppercase H):
#OneToMany(mappedBy = "userHome")
private Set<Key> keys;
The fields/properties you reference in a field like mappedBy should have the exact name and case of the field in the JavaBean.

Related

Error creating bean with name 'jpaMappingContext': Invocation of init method failed;

Click Link for pic
Please help I am stuck in error after error
Need to create a spring data model and pass the test case
Spring data models are
#Entity
public class Cart {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer cartId;
private Double totalAmount;
#OneToOne
#JoinColumn(name = "userId")
private User user;
#OneToMany(mappedBy = "cart")
private List<CartProduct> cartProducts;
//getter and setter and constructor
}
#Entity
public class CartProduct {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer cpId;
#ManyToOne
#JoinColumn(name = "cartId")
private Cart cart;
#ManyToOne
#JoinColumn(name = "productId")
private Product product;
private Integer quantity = 1;
//getter and setter and constructor
}
#Entity
public class Category {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer categoryId;
private String categoryName;
//getter and setter and constructor
}
#Entity
public class Product {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer productId;
private String productName;
private Double price;
#ManyToOne
#JoinColumn(name ="userId")
private User seller;
#ManyToOne
#JoinColumn(name ="userId")
private Category category;
//getter and setter and constructor
}
The main issue is role and user can't able to create
many-to-many relations
#Entity
public class Role {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
Integer roleId;
String role;
#ManyToMany(mappedBy = "roles")
Set<User> users = new HashSet<>();
//getter setter and constructor
}
#Entity
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer userId;
private String username;
private String password;
// Implement Roles
#ManyToMany
#JoinTable(name="user_Role",joinColumns = #JoinColumn(name="userId")
,inverseJoinColumns = #JoinColumn(name="roleId"))
private Set<Role> roles = new HashSet<Role>();
}
https://pastebin.com/T34SbwMy
the test case is in the link and can't able to pass the test case.
Thanks in advance.

JPA do not allow binary one to many relationship

I have 2 entities as below:
Course
#Entity
public class Course {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(mappedBy = "course", cascade = {CascadeType.PERSIST, CascadeType.REMOVE, CascadeType.MERGE})
private List<Comment> comments;
Comment
#Entity
public class Comment {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String comment;
#ManyToOne(targetEntity = Course.class)
private Course course; //Error: 'Many To One' attribute type should not be 'Course'
I follow luv2code.com course but he use Spring MVC and it work just find, but when I do this in spring boot, it always show the error, please help me fix this!
Try something like this:
#Entity
public class Course {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(mappedBy = "course")
private List<Comment> comments;
And your comment entity:
#Entity
public class Comment {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String comment;
#ManyToOne(cascade = CascadeType.ALL)
private Course course;
#Entity
public class Course {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(cascade = CascadeType.ALL,
fetch = FetchType.LAZY,
orphanRemoval = true)
private List<Comment> comments = new ArrayList<Comment>();
#Entity
public class Comment {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String comment;
}
You don't to define ManyToOne Mapping in your comment Entity.

How to set entity relation mapping for two entites of same type inside another

Example: I have a Spring Boot, HSQLB, JPARepository Project with
#Entity
public class LetterEntity{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private AddressEntity fromAddress;
private AddressEntity toAddress;
}
#Entity
public class AddressEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private int id;
private LetterEntity letter;
}
So, each Letter have two fields of type AddressEntity. Each AddressEntity has a field of its LetterEntity.
How I need to set the relations mappings and cascading?

JPA one to many, fetch children with specific column value

I have two entities in one to many relationship in my spring-data-jpa project.
Parent entity -
#Entity
#Table(name = "code_group")
public class CodeGroup implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private Long id;
#NaturalId
#Column(nullable = false)
private String entityId;
#OneToMany
#JoinColumn(name = "codeGroupId", referencedColumnName = "entityId")
private List<SystemCode> systemCodes;
// .. getters setters
}
Child entity -
#Entity
#Table(name = "system_code")
public class SystemCode implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private Long id;
#Column(nullable = false)
private String codeGroupId;
#Column(nullable = false)
#Enumerated(EnumType.STRING)
private ActiveOrInactive status;
// getters and setters
}
status column is of enum type, it can only have Active or Inactive value.
My existing code works fine. It is fetching code group with associated system codes. I want to filter system code with status='Active'. How to do this?
Try like this:
#OneToMany
#JoinColumn(name = "codeGroupId", referencedColumnName = "entityId")
#Where(clause = "status= 'Active'")
private List<SystemCode> systemCodes;
You can create such methods in your repo:
List<CodeGroup> getAllBySystemCodes_Status(ActiveOrInactive status);
default List<CodeGroup> getAllActive() {
return getAllBySystemCodes_Status(ActiveOrInactive.Active);
}
default List<CodeGroup> getAllInactive() {
return getAllBySystemCodes_Status(ActiveOrInactive.Inactive);
}

How to get rid with infinity recursion

i'm trying to solve infinity recursion issue with no success !
project: spring boot and postgresql
i have 3 entities : course, course outline and course schedule :
public class Course implements Serializable {
private static final long serialVersionUID = -6645577819394287204L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private UUID id;
#OneToMany(mappedBy = "course", cascade = CascadeType.REMOVE)
#OrderBy("rank ASC")
private List<CourseOutline> outlines;
....
}
public class CourseOutline implements Serializable {
private static final long serialVersionUID = -6645577819394287204L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private UUID id;
#ManyToOne
#JoinColumn(name = "course", nullable = false)
#JsonIgnore
private Course course;
private Integer rank;
#OneToMany(mappedBy = "outline", cascade = CascadeType.REMOVE)
#OrderBy("day DESC, started ASC")
private Set<CourseSchedule> schedules;
...
}
public class CourseSchedule implements Serializable {
private static final long serialVersionUID = -6645577819394287204L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private UUID id;
#ManyToOne
#JoinColumn(name = "instructor", nullable = true)
#JsonManagedReference
private Person instructor;
#ManyToOne
#JoinColumn(name = "outline", nullable = false)
#JsonIgnore
private CourseOutline outline;
...
}
in REST API i make a call to retrieve a List of CourseOutline by course
using CourseOutline Repository :
List<CourseOutline> findAllByCourse(Course course);
but i get below error :
Could not write JSON: Infinite recursion (StackOverflowError); nested
exception is com.fasterxml.jackson.databind.JsonMappingException:
Infinite recursion (StackOverflowError) (through reference chain:
java.util.ArrayList[2]-myDomain.api.models.entities.CourseOutline[\"schedules\"])"

Resources