how to display DTO correctly in Spring boot - java

I have two Entities in my spring boot application. I am working with dtos and displaying my dto in the end. But I am getting the wrong output from my getRequest. My first entity is MeetingSetting which can have multiple MeetingTimes and inside MeetingTime I have meetingName as a foreign key. I want to display meetingTime like this:
{
"id": 1,
"date": "2021-06-31",
"startTime": "15:30",
"endTime": "16:30",
"meetingName": "Test"
}
But I am getting instead this one:
{
"id": 1,
"date": "2021-06-31",
"startTime": "15:30",
"endTime": "16:30",
"meetingName": {
"id": 1,
"meetingName": "Tewasddweewrst2",
"meetingUrl": null,
"meetingPw": ""
}
}
Could someone take a look at my code and tell me what I am doing wrong?
MeetingSetting Entity::
#Entity
#Table(name = "meeting_settings")
#Setter
#Getter
public class MeetingsSetting implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "meeting_name", unique = true)
private String meetingName;
#Column(name = "meeting_url")
private String meetingUrl;
#Column(name = "meeting_pw")
private String meetingPw;
#OneToMany(mappedBy = "meetingName", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
private Set<MeetingTime> meetingTime = new HashSet<>();
}
MeetingSettingDTO:
#Getter
#Setter
public class MeetingSettingDTO {
private Long id;
#NotNull
private String meetingName;
#NotNull
private String meetingUrl;
#NotNull
private String meetingPw;
#JsonIgnore
private Set<MeetingTime> meetingTime;
}
MeetingTimeEntity:
#Entity
#Table(name = "meeting_times")
#Getter
#Setter
public class MeetingTime implements Serializable {
#JsonIgnore
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "meeting_date")
private String date;
#Column(name = "start_time")
private String startTime;
#Column(name = "end_time")
private String endTime;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "meeting_name" , referencedColumnName = "meeting_name")
private MeetingsSetting meetingName;
}
MeetingTimeDTO:
#Getter
#Setter
public class MeetingTimeDTO {
private Long id;
#NotNull
private String date;
#NotNull
private String startTime;
#NotNull
private String endTime;
private MeetingSettingDTO meetingName;
}
In my service I am first getting MeetingTime as an entity from my repository then converting it to DTO and returning it for my controller:
#Service
public class MeetingTimeService {
ModelMapper modelMapper = new ModelMapper();
#Autowired
MeetingTimeRepository meetingTimeRepository;
public List<MeetingTimeDTO> findAllMeetingTimes(){
List<MeetingTime> meetingTimeList = meetingTimeRepository.findAll();
return meetingTimeList.stream()
.map(this::convertToDto)
.collect(Collectors.toList());
}
private MeetingTimeDTO convertToDto(MeetingTime meetingTime) {
MeetingTimeDTO meetingTimeDTO = modelMapper.map(meetingTime, MeetingTimeDTO.class);
return meetingTimeDTO;
}
}
Controller:
#GetMapping(value = "/" )
public List<MeetingTimeDTO> getAllTimes() {
return meetingTimeService.findAllMeetingTimes();
}

In MeetingTimeDTO:
private MeetingSettingDTO meetingName;
The type needs to be changed to:
private string meetingName;
I have not worked with ModelMapper so cannot help you with how to map a specific field from the related object but this answer here seems to provide the info needed.

Related

Spring Boot API: Failing to save object to Database using Spring Boot

I have already built projects similar to this one, I even based this one in a different project I have. Thing is, I don't see why it keeps failing when I try to save an object to the Database. These are my Classes:
Car
#Data
#AllArgsConstructor
#NoArgsConstructor
#Entity(name = "cars")
public class Car {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
#Column
#NotBlank
private String brand;
#Column
#NotBlank
private String model;
#Column
#NotBlank
private String color;
#Column
#NotBlank
private int kilometers;
#Column(name = "fabrication_date")
private LocalDate fabricationDate;
#Column
#PositiveOrZero
private float price;
#Override
public String toString() {
return "------------------------------------------------------------"+ "\n"
+brand + " - " + model;
}
#OneToMany(mappedBy = "car")
#JsonBackReference(value = "car-purchases")
private List<Purchase> purchases;
}
Purchase
#Data
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Table(name = "purchases",
uniqueConstraints = { #UniqueConstraint(columnNames =
{ "user_id", "car_id" }) })
public class Purchase {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
#Column(name = "creation_date")
private LocalDate creationDate;
#Column
private float price;
#ManyToOne
#JoinColumn(name = "user_id")
private User user;
#ManyToOne
#JoinColumn(name = "car_id")
private Car car;
}
This is the Add to Database function:
#Override
public CarOutDTO addCar(CarInDTO carInDTO) {
Car car = new Car();
modelMapper.map(carInDTO, car);
car.setFabricationDate(LocalDate.now());
car.setKilometers(0);
Car newCar = carRepository.save(car); <--- It fails here
CarOutDTO carOutDTO = new CarOutDTO();
modelMapper.map(car, carOutDTO);
return carOutDTO;
}
And, this is the info that comes when I try sending a POST:
I can't find the error here, I assume it has something to do with this part, maybe the #JsonBackReference part?
#OneToMany(mappedBy = "car")
#JsonBackReference(value = "car-purchases")
private List<Purchase> purchases;

how to save bidrectional entity with dto

I have two spring boot entities MeetingSetting and MeetingTime, MeetingSetting can have multiple MeetingTimes. I am trying to save these to at the same time with the DTO structure, so I can avoid the circular reference problem when I am getting MeetingTimes. Saving partially works. MeetingSettings has a property called meetingName which is a foreign key in meetingTimes. Everything except meetingName is saved which is for some reason null, but I can not find the reason, could someone maybe look at my code and tell me what I am missing?
MeetingSetting Entity:
#Entity
#Table(name = "meeting_settings")
#Setter
#Getter
public class MeetingsSetting implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "meeting_name", unique = true)
private String meetingName;
#Column(name = "meeting_url")
private String meetingUrl;
#Column(name = "meeting_pw")
private String meetingPw;
#OneToMany(mappedBy = "meetingName", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
private Set<MeetingTime> meetingTime = new HashSet<>();
}
MeetingSettingDTO:
#Getter
#Setter
public class MeetingSettingDTO {
private Long id;
#NotNull
private String meetingName;
#NotNull
private String meetingUrl;
#NotNull
private String meetingPw;
private Set<MeetingTime> meetingTime;
}
MeetingTime Entity:
#Entity
#Table(name = "meeting_times")
#Getter
#Setter
public class MeetingTime implements Serializable {
#JsonIgnore
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "meeting_date")
private String date;
#Column(name = "start_time")
private String startTime;
#Column(name = "end_time")
private String endTime;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "meeting_name" , referencedColumnName = "meeting_name")
private MeetingsSetting meetingName;
}
MeetingTimeDTO:
#Getter
#Setter
public class MeetingTimeDTO {
private Long id;
#NotNull
private String date;
#NotNull
private String startTime;
#NotNull
private String endTime;
private Set<MeetingSettingDTO> meetingSettings;
}
And finally the controller where I am saving everything (Just save method):
#PostMapping("/")
public void saveMeeting(#RequestBody MeetingSettingDTO meetingSettingDTO){
MeetingsSetting meetingsSetting = new MeetingsSetting();
meetingsSetting.setMeetingName(meetingSettingDTO.getMeetingName());
meetingsSetting.setMeetingPw(meetingSettingDTO.getMeetingPw());
meetingsSetting.setMeetingUrl(meetingSettingDTO.getMeetingUrl());
Set<MeetingTime> meetingTimeSet = meetingSettingDTO.getMeetingTime();
meetingsSetting.setMeetingTime(meetingTimeSet);
meetingSettingService.saveMeeting(meetingsSetting);
}
My service is just implementing a jpaRepository which takes MeetingSetting as parameter
In your MeetingTime entity class you have a parent:
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "meeting_name" , referencedColumnName = "meeting_name")
private MeetingsSetting meetingName;
You have to set it explicitly for each MeetingTime, so add this:
Set<MeetingTime> meetingTimeSet = meetingSettingDTO.getMeetingTime();
meetingTimeSet.forEach(m -> m.meetingName(meetingsSetting));

how to save entities in a relation to database in spring boot

I have a spring boot application with two entities in a relationship. MeetingSetting and MeetingTime meetingSetting can have unlimited meetingTimes. So far the databases are generating without problem, but When I try to save my Entity they are saved but different from each other, they are saved independently. Meaning MeetingName which is a foreign key inside MeetingTime is not saved but seen as null (I debugged and tried finding out why but could not find anything) THe other values are saved-
could someone point me out what my error is?
this is the json I am sending:
{
"meetingName":"TEst",
"meetingPw":"",
"meetingTime":[
{
"date":"2021-05-31",
"startTime":"15:30",
"endTime":"16:30"
},
{
"date":"2021-06-21",
"startTime":"15:30",
"endTime":"17:30"
},
{
"date":"2021-06-21",
"startTime":"11:01",
"endTime":"11:01"
}
]
}
MeetingSettings:
#Entity
#Table(name = "meeting_settings")
#Data
public class MeetingsSetting {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "meeting_name", unique = true)
private String meetingName;
#Column(name = "meeting_url")
private String meetingUrl;
#Column(name = "meeting_pw")
private String meetingPw;
#OneToMany(mappedBy = "meeting_Name", cascade = CascadeType.ALL)
private Set<MeetingTime> meetingTime = new HashSet<>();
}
MeetingTime:
#Entity
#Table(name = "meeting_times")
#Data
public class MeetingTime {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "meeting_date")
private String date;
#Column(name = "start_time")
private String startTime;
#Column(name = "end_time")
private String endTime;
#ManyToOne
#JoinColumn(name = "meeting_name" ,insertable = false, updatable = false , referencedColumnName = "meeting_name")
private MeetingsSetting meeting_Name;
}
this is how I try to save the entity:
#RestController
#RequestMapping("/api/meetingSetting")
public class MeetingSettingController {
#Autowired
MeetingSettingService meetingSettingService;
#PostMapping("/")
public void saveMeeting(#RequestBody MeetingsSetting meetingsSetting){
meetingSettingService.saveMeeting(meetingsSetting);
}
}
My service calls the save method of an jpaRepository.
In a bi-directional One to Many, you have to synchronize both sides of the association.
You can simply iterate over all MeetingTime objects and set the corresponding MeetingSetting to it.
Your MeetingSettingService's saveMeeting method could do this:
public void saveMeeting(MeetingsSetting meetingsSetting) {
// ...
// here you're synchronizing both sides of the association
meetingsSetting.getMeetingTime()
.forEach(mt -> mt.setMeetingSetting(meetingSetting));
// ...
repository.save(meetingSetting);
}
Solution to my question, I am not sure if this is a good or correct way of solving this maybe someone can advice me a better solution:
#Entity
#Table(name = "meeting_times")
#Data
public class MeetingTime implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "meeting_date")
private String date;
#Column(name = "start_time")
private String startTime;
#Column(name = "meeting_name")
private String meeting_name;
THIS IS THE PART WHICH IS CALLED FROM THE METHOD INSIDE MEETINGSCONTROLLER
#Column(name = "end_time")
private String endTime;
#ManyToOne
#JoinColumn(name = "meeting_name" ,insertable = false, updatable = false, referencedColumnName = "meeting_name")
private MeetingsSetting meetingName;
}
MeetingsTime Entity:
#RestController
#RequestMapping("/api/meetingSetting")
public class MeetingSettingController {
#Autowired
MeetingSettingService meetingSettingService;
#PostMapping("/")
public void saveMeeting(#RequestBody MeetingsSetting meetingsSetting){
meetingsSetting.getMeetingTime()
.forEach(mt -> mt.setMeeting_name(meetingsSetting.getMeetingName()));
// ...
meetingSettingService.saveMeeting(meetingsSetting);
}
}

Spring JPA One To Many Infinite Recursion

im trying to return to a JPA data (converted to DTO, ofcourse) where it has a #OneToMany and #ManyToOne bidirectional relationship. Im currently apply thing fix. The problem is that the output is recusrive. comments has post has comments then has posts (comments -> post -> coments -> so on..).
I only wnat to have something like this
{
"post_id": 1
"user": {
// user data
},
"description": "some description",
"images": "{images,images}",
"tags": "{tags, tags}",
"comments": [
{
//some comments data
},
{
//some comments data
}
]
"lastUpdated": "2020-04-08T14:23:18.000+00:00"
}
Here are my code
This is my Posts.class
#Data
#Entity
#Table(name = "posts")
#EntityListeners(AuditingEntityListener.class)
public class Posts {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "post_id")
private Long post_id;
#ManyToOne
#JoinColumn(name = "user_id", nullable = false)
private Users user;
#Column(name = "description")
private String description;
#Column(name="images")
private String images;
#Column(name="tags")
private String tags;
#OneToMany(
fetch = FetchType.LAZY,
mappedBy = "post",
cascade = CascadeType.ALL,
orphanRemoval = true
)
#JsonIgnoreProperties(value = { "comments" ,"hibernateLazyInitializer", "handler" }, allowSetters = true)
//#JsonManagedReference
private List<Comments> comments;
#LastModifiedDate
#Column(name = "last_updated")
private Date lastUpdated;
public void addComments(Comments comment) {
this.comments.add(comment);
}
}
Here is my PostDTO.class
#Data
public class PostDTO {
private Long post_id;
private UserDTO user;
private String description;
private String images;
private String tags;
private List<CommentsDTO> comments;
private Date lastUpdated;
}
This is my Comments.class
#Data
#Entity
#Table(name = "comments")
#EntityListeners(AuditingEntityListener.class)
public class Comments {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name="comment_id")
private Long comment_id;
#OneToOne
#JoinColumn(name = "user_id")
private Users user;
#Column(name = "description")
private String description;
#Column(name="images")
private String images;
#ManyToOne
#JoinColumn(name ="post_id" , nullable = false)
#JsonIgnoreProperties(value = { "post" ,"hibernateLazyInitializer", "handler" }, allowSetters = true)
//#JsonBackReference
private Posts post;
#Column(name="last_updated")
#LastModifiedDate
private Date lastUpdated;
}
Here is my CommentsDTO.class
#Data
public class CommentsDTO {
private Long comment_id;
private UserDTO user;
private String description;
private PostDTO post;
private String images;
private Date lastUpdated;
}
Here is my REST Controller
#GetMapping
public #ResponseBody ResponseEntity<List<PostDTO>> getAll() throws Exception {
return new ResponseEntity<List<PostDTO>>(service.getAll(), HttpStatus.OK);
}
Here is my service
public List<PostDTO> getAll() throws Exception {
return repo.findAll()
.stream()
.map(this::convert)
.collect(Collectors.toList());
}
private PostDTO convert(Posts e) {
return mapper.map(e, PostDTO.class);
}
Hope someone can shed light on my issue. Kinda lost as of this time.
Problem is when you convert Post into PostDTO then by using ModelMapper it calls all field's getter of Post for PostDTO. So this happened recursively for this
mapper.map(e, PostDTO.class)
So, just remove private PostDTO post from CommentDTO ,
then modelmapper don't try to set PostDTO->comment-> post field.
And you don't need bidirectional relation in DTO. DTO is all about what you want to show in response.
You are breaking the json serialization cycle on the wrong class.
You are sending a list of PostDTO, but applied JsonBackReference to Comments and JsonManagedReference to Posts
Update
Note that ObjectMapper class, JsonManagedReference and JsonBackReference may from 2 packages
com.fasterxml.jackson.databind.ObjectMapper
com.fasterxml.jackson.annotation.JsonManagedReference
com.fasterxml.jackson.annotation.JsonBackReference
or:
org.codehaus.jackson.map.ObjectMapper
org.codehaus.jackson.annotate.JsonManagedReference
org.codehaus.jackson.annotate.JsonBackReference
If you are not consistent between all of them, the mis-matched annotation will be ignored and you will still experience infinite loop during serialization.
Use JsonIgnoreProperties along with Manage and backreference .
#Data
#Entity
#Table(name = "comments")
#EntityListeners(AuditingEntityListener.class)
public class Comments {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name="comment_id")
private Long comment_id;
#OneToOne
#JoinColumn(name = "user_id")
private Users user;
#Column(name = "description")
private String description;
#Column(name="images")
private String images;
#ManyToOne
#JoinColumn(name ="post_id" , nullable = false)
#JsonIgnoreProperties(value = { "comments" ,"hibernateLazyInitializer", "handler" }, allowSetters = true)
#JsonBackReference
private Posts post;
#Column(name="last_updated")
#LastModifiedDate
private Date lastUpdated;
}
And Your Post class should be
#Data
#Entity
#Table(name = "posts")
#EntityListeners(AuditingEntityListener.class)
public class Posts {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "post_id")
private Long post_id;
#ManyToOne
#JoinColumn(name = "user_id", nullable = false)
private Users user;
#Column(name = "description")
private String description;
#Column(name="images")
private String images;
#Column(name="tags")
private String tags;
#OneToMany(
fetch = FetchType.LAZY,
mappedBy = "post",
cascade = CascadeType.ALL,
orphanRemoval = true
)
#JsonIgnoreProperties(value = { "post" ,"hibernateLazyInitializer", "handler" }, allowSetters = true)
#JsonManagedReference
private List<Comments> comments;
#LastModifiedDate
#Column(name = "last_updated")
private Date lastUpdated;
public void addComments(Comments comment) {
this.comments.add(comment);
}
}
Also I would suggest to Use Getter and Setter annotation instead of #Data .Because Tostring() method will cause recursion also .

Create a product in a category hibernate - Transcient issue

I use two class as models to build a JSON :
The productCreateRequestModel:
#Getter #Setter
public class ProductCreateRequestModel {
private Long id;
private String name;
private double price;
private int qty;
private String imgPath;
private CategoryRequestCreateProductModel category;
}
My CategoryRequestCreateProductModel
#Getter #Setter
public class CategoryRequestCreateProductModel {
private Long id;
private String name;
private String categoryKeyId;
}
I created 2 entities to manage categories and products.
#Entity
#Table(name="products")
#Getter #Setter
public class ProductEntity {
#Id
#GeneratedValue(strategy= GenerationType.IDENTITY)
private Long id;
#Column(nullable = false)
private String productKeyId;
// many to one relationship with category
#ManyToOne
#JoinColumn(name = "category_id")
private CategoryEntity category;
#Column(nullable = false)
private String name;
#Column(nullable = false)
private double price;
#Column(nullable = false)
private int qty;
private String imgPath;
}
And :
#Entity
#Table(name="categories")
#Getter #Setter
public class CategoryEntity {
#Id
#GeneratedValue(strategy= GenerationType.IDENTITY)
private Long id;
#Column(length = 30, nullable = false)
private String categoryKeyId;
#Column(nullable = false)
private String name;
#ManyToOne(optional = true, fetch = FetchType.LAZY)
#JoinColumn(name="parent_id", nullable=true)
private CategoryEntity parentCategory;
// allow to delete also subcategories
#OneToMany(mappedBy="parentCategory", cascade = CascadeType.ALL)
private List<CategoryEntity> subCategories;
//Here mappedBy indicates that the owner is in the other side
#OneToMany(fetch = FetchType.EAGER, mappedBy = "category", cascade = CascadeType.REMOVE)
private List<ProductEntity> products;
}
This generated this table in the database.
In my controller:
public ProductRestResponseModel createProduct(#RequestBody ProductCreateRequestModel productCreateRequestModel) throws Exception {
ProductRestResponseModel returnValue = new ProductRestResponseModel();
if(productCreateRequestModel.getName().isEmpty() || productCreateRequestModel.getPrice() <= 0)
throw new ApplicationServiceException(ErrorMessages.MISSING_REQUIRED_FIELDS.getErrorMessage());
ModelMapper modelMapper = new ModelMapper();
ProductDto productDto = modelMapper.map(productCreateRequestModel, ProductDto.class);
ProductDto createdProduct = productService.createProduct(productDto);
returnValue = modelMapper.map(createdProduct, ProductRestResponseModel.class);
return returnValue;
}
In my Service I use the DTO:
#Override
public ProductDto createProduct(ProductDto productDto) {
ProductDto returnValue = new ProductDto();
if (productRepository.findByName(productDto.getName()) != null)
throw new ApplicationServiceException("Record already in Database");
ModelMapper modelMapper = new ModelMapper();
ProductEntity productEntity = modelMapper.map(productDto, ProductEntity.class);
String productKeyId = utils.generateProductKeyId(30);
productEntity.setProductKeyId(productKeyId);
ProductEntity storedProduct = productRepository.save(productEntity);
returnValue = modelMapper.map(storedProduct, ProductDto.class);
return returnValue;
}
My issue is when I send a post request with this object :
{
"name": "Pizza",
"price": 344.0,
"qty": 15,
"imgPath": "new/pathImage",
"category": {
"categoryKeyId": "23ume70Fu6yqyGUWfQkW110P4ko3gZ",
"name": "CatName"
}
}
When i send this request I obtain an error message : org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.app.ws.io.entity.ProductEntity.category -> com.app.ws.io.entity.CategoryEntity
My problem is that the Category already exists in the database and that i just need to set the foreign key in the product table

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