Is there any good way to ignore some request query parameters from binding to DTO parameters?
#Data // setters and getters
class Dto {
private String param1;
private String param2;
}
#GetMapping("/hello-world")
#ResponseBody
public ResponseEntity<Dto> sayHello(Dto params)
{ ... }
I would like to exclude binding of specific param in such case.
After some research I can't find any solution for it, any help?
Related
i have a use case where the user can send following params with get request
GET localhost/8080/users?filter=alex
OR
GET localhost/8080/users?suffixFilter=lex
OR
GET localhost/8080/users?prefixFilter=a
is it possible to add only one request param instead of 3 in controller
e.g.
instead of
#GetMapping("/users")
#ResponseBody
public String getFoos(#RequestParam String filter, #RequestParam String prefixFilter , #RequestParam String suffixFilter) {
return "ID: " + id;
}
is it possible to create a dynamic one which includes those three variantes? I was thinking creating class like this
public class FilterCreteria {
private String filter;
private String suffixFilter;
private String prefixFilter;
}
and then passing this to controller
#GetMapping("/users")
#ResponseBody
public String getFoos(#RequestParam FilterCreateria filter) {
return "ID: " + id;
}
the problem is if i send filter=alex the other attributes in the class FilterCreteria is null and i want to avoid this null.
What i searching for:
is there other way of making this possible?
if my suggestion is ok, how to avoid null attributes when the user only sends one queryparam like filter=alex?
Let me explain a problem. Suppose I have an entity class User:
public class User {
private UUID id;
private String login;
private String password;
private String firstName;
private String lastName;
private String email;
private int age;
// ... more fields and default getters and setters
}
In addition, I have two DTO classes:
public class UserLogin {
private UUID id;
private String login;
// ... getters and setters
}
public class UserLoginEmail {
private UUID id;
private String login;
private String email;
// ... getters and setters
}
Let's take a look to class UserController that has UserLoginEmail as request body and UserLogin as response body:
#RestController("/users")
public class UserController {
#PutMapping
public UserLogin someRequest(UserLoginEmail user) {
// ...
}
}
What is the best way to create some kind of projections in Spring Boot? Can I create an interface with required fields and just put them in the Java method as parameters (or some other way)? I want to build DTO classes with the least effort and agile in my code.
You could use JSON Views with Jackson with which you could define different views on a per endpoint basis (check https://www.baeldung.com/jackson-json-view-annotation for more details).
But in your case, I wouldn't do that. One of your DTOs is a request and the other is a response so you shouldn't mix them together in a single DTO. Even more than that, I don't really like JSON Views because they are simply hard to follow and the code becomes harder to read. Abstractions and code reusability are usually good but it makes the code much harder to read and for the case of DTOs I much more prefer to be explicit and have multiple DTOs even that they are similar. With this approach, you will make it possible to easily change one of the DTOs without affecting anything else, which is not the case when you reuse them in any way.
Having said that, keep both DTOs, but I would rename them: UserLoginRequest and UserLoginResponse.
I have two entities: Book and Category and a repository for both. In the controller, I have set up the methods correctly as such:
#RequestMapping(value="/books", method = RequestMethod.GET)
#CrossOrigin
public #ResponseBody List<Book> bookListRest() {
return (List<Book>) bookRepository.findAll();
}
This obviously shows all books and every field in the entity that isn't #JsonIgnore'd. The problem is, I need to have:
One page with Book data (book name, author name, isbn..) without category
One page with Category data (Category name) without books
One page with Everything (book data along with categories where they belong in)
How can one accomplish this?
I somehow need to in a way ignore #jsonignore on some occasions. Should I make a new entity that extends say, Question and also make a repository for that? Surely that can't be the correct way to do this.
As khalid Ahmed Said you can use costum dtos or you can add Filters to ignore specific fields in Jackson. First, we need to define the filter on the java object:
#JsonFilter("myFilterBook")
public class Book{
...
}
#JsonFilter("myFilterCategory")
public class Category{
...
}
Before you return your ResponseBody you try to use ObjectMapper (Jackson):
The case of one page with Book data (book name, author name, isbn..) without category:
ObjectMapper mapper = new ObjectMapper();
SimpleBeanPropertyFilter theFilter = SimpleBeanPropertyFilter
.serializeAllExcept("category");
FilterProvider filters = new SimpleFilterProvider()
.addFilter("myFilterBook", theFilter);
String dtoAsString = mapper.writer(filters).writeValueAsString(book);
You can do the same think by putting what you want o ignore for the other example.
And for more details to ignore field during marshalling with jackson you can check here
What about using DTOs data transfer objects
you can create multiple DTOs to use them in the response of your API
DTO is a pojo class that customize the returning data from your entity
public class BookWithoutCategoryDTO {
private String name;
private String authorName;
.....
/// and make setters and getters for them
}
public class BookWithCategoryDTO {
private String name;
private String authorName;
private String category;
.....
/// and make setters and getters for them
}
and create your custom mapper to convert from Book to BookDTO
I would like to know how to access a deep collection class attribute in a GET request. My endpoint maps my query strings through #ModelAttribute annotation:
Given that:
public class MyEntity
{
Set<Item> items;
Integer status;
// getters setters
}
public class Item
{
String name;
// getters setters
}
And my GET request: localhost/entities/?status=0&items[0].name=Garry
Produces bellow behavior?
#RequestMapping(path = "/entities", method = RequestMethod.GET)
public List<MyEntity> findBy(#ModelAttribute MyEntity entity) {
// entity.getItems() is empty and an error is thrown: "Property referenced in indexed property path 'items[0]' is neither an array nor a List nor a Map."
}
Should my "items" be an array, List or Map? If so, there´s alternatives to keep using as Set?
Looks like there is some problem with the Set<Item>.
If you want to use Set for the items collection you have to initialize it and add some items:
e.g. like this:
public class MyEntity {
private Integer status;
private Set<Item> items;
public MyEntity() {
this.status = 0;
this.items = new HashSet<>();
this.items.add(new Item());
this.items.add(new Item());
}
//getters setters
}
but then you will be able to set only the values of this 2 items:
This will work: http://localhost:8081/map?status=1&items[0].name=asd&items[1].name=aaa
This will not work: http://localhost:8081/map?status=1&items[0].name=asd&items[1].name=aaa&items[2].name=aaa
it will say: Invalid property 'items[2]' of bean class MyEntity.
However if you switch to List:
public class MyEntity {
private Integer status;
private List<Item> items;
}
both urls map without the need to initialize anything and for various number of items.
note that I didn't use #ModelAttribute, just set the class as paramter
#GetMapping("map")//GetMapping is just a shortcut for RequestMapping
public MyEntity map(MyEntity myEntity) {
return myEntity;
}
Offtopic
Mapping a complex object in Get request sounds like a code smell to me.
Usually Get methods are used to get/read data and the url parameters are used to specify the values that should be used to filter the data that has to be read.
if you want to insert or update some data use POST, PATCH or PUT and put the complex object that you want to insert/update in the request body as JSON(you can map that in the Spring Controller with #RequestBody).
I've the following domain and needs to return selected field in response to client. How can I achieve that using Spring?
public class Vehicle {
private String vehicleId;
private Long dateCreated;
private String ownerId;
private String colourCode;
private String engineNumber;
private String transmission;
//getters & setters
}
My objective is to return only colourCode and transmission fields to client request. I've read about DTO and seems like I can achieve my objective with DTO but I don't find any good example how to implement it. Is DTO is the correct way to achieve my objective ?
Basically you just create VehicleDTO class with parameters you need
public class VehicleDTO {
private String colourCode;
private String transmission;
//getters and setters
}
and then in your code you construct VehicleDTO from your Vehicle class. Fortunately, we have BeansUtils class from Spring, that uses reflection to copy properties of one object to another, because you do not want to repeat logic for copying properties for every object. So it would be something like:
BeanUtils.copyProperties(v1, dto);
At the end your return VehicleDTO in your response instead of Vehicle
You can return IVehicle interface which exposes your properties of choice
public interface IVehicle {
String getTransmission();
String getColourCode();
}
and your Vehicle implents it
public class Vehicle implements IVehicle{ }
There are various ways you can achieve what you want.
You can add relevant usecase / APi specific DTO for the resource.
e.g. If your API return the vehical general details you may want to expose some level of details,
public class VehicleDetailsDTO {
private String colourCode;
private String transmission;
private String engineNumber; //more
//getters and setters
}
You can then either use BeanUtils or Dozzer to convert your Vehical resource to transportable object like your DTO.
BeanUtils : http://commons.apache.org/proper/commons-beanutils/
Dozzer : http://dozer.sourceforge.net/documentation/mappings.html
Assuming you use JSON as output format and Jackson as serialization engine (default in Spring MVC), you can tell Jackson to not serialize null properties. Now you just need to populate the properties you need and can return the original business object.