In my Spring Boot rest api, I have the following class:
#Entity
#Table(name="Items")
#JsonPropertyOrder({ "itemId", "description", "viewed" })
public class Item {
#ApiModelProperty(notes="Id of the item.", required=true, value="100000")
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#JsonProperty(access=Access.READ_ONLY)
private int itemId = 0;
#ApiModelProperty(notes="Item description.", required=true, value="Item1")
#NotNull
#Size(min=1, max=256)
private String description;
private int viewed;
public int getItemId() {
return this.itemId;
}
public String getDescription() {
return this.description;
}
public void setDescription(String description) {
this.description = description;
}
public int getViewed() {
return this.viewed;
}
}
When I execute the request, the JsonPropertyOrder is respected, however, in the Swagger UI (and the Swagger doc), the properties are listed as description, itemId, viewed. I.e. alphabetical. I never turned on alphabetical sorting, so not sure why its doing that... any way to turn that off? It's doing that to all my classes which are laid out in common sense / logical order...
You can define the order in which the properties are going to be shown with ApiModelProperty#position.
Example:
class MyClass {
#ApiModelProperty(position = 0)
String myFirstProperty;
#ApiModelProperty(position = 1)
String mySecondProperty;
}
It's not the most convenient method, but I couldn't find any other way to achieve this...
Related
I'm building a POJO class to match some requests coming my way in a REST API implemented on SpringBoot. Some of the data has to be given to me, otherwise I am not willing to even serve the request. To make sure the client gives me at least what I absolutely need, I have used Lombok's #NonNull:
#Data
public class ProductRequestBody implements Serializable
{
private String name;
private String category;
private String description;
private String abbreviation;
private String labelColor;
private Double cost;
public ProductRequestBody()
{
}
#JsonCreator
public ProductRequestBody(#NonNull #JsonProperty("name") String name,
#NonNull #JsonProperty("category") String category,
#JsonProperty("description") String description,
#NonNull #JsonProperty("cost") Double cost)
{
this.name = name;
this.category = category;
this.description = description;
this.cost = cost;
}
}
(I completely understand that handling monetary quantities as Doubles is a no-no; this is just an example.
Processing this from my controller is as easy as a listener on the /products endpoint like so:
#PostMapping(value = "/products")
public Product postProduct(#RequestBody ProductRequestBody newProduct)
{
// ...
// Serve the request appropriately
// ...
}
Now, if I receive a POST request with a null field that has not been marked as #NonNull, like the following, I can serve it without issue:
{
"name": "Some Product Name",
"category": "Some Product Category",
"cost" : 10.0,
"description": null
}
My goal, however, is to be able to handle JSON requests that simply don't even have the fields they don't care about. That is, I want to be able to serve the following as well, and I currently can't:
{
"name": "Some Product Name",
"category": "Some Product Category",
"cost" : 10.0,
// No "description" field in this payload
}
How could I go about doing this? The less code, the better, as always.
If you use spring-boot and lombok you can simplify your class to be like this:
#Data
public class ProductRequestBody implements Serializable {
#NonNull
private String name;
#NonNull
private String category;
#NonNull
private Double cost;
private String description;
private String abbreviation;
private String labelColor;
}
it will return 400 if name, category or cost will be not provided and 200 otherwise.
Spring handles serializing and deserializing json without any issue.
You should let spring handle it.
You can try the following.
#Data
public class ProductRequestBody implements Serializable {
#NonNull
private String name;
#NonNull
private String category;
private String description;
private String abbreviation;
private String labelColor;
#NonNull
private Double cost;
}
If you really want to follow the pattern of creating a constructor, then you should create a constructor with only the #NonNull fields and create getter of others (lombok handles that for you). If you want to add #JsonProperty then you need to create separate getter.
#Data
public class ProductRequestBody implements Serializable
{
private String name;
private String category;
private String description;
private String abbreviation;
private String labelColor;
private Double cost;
public ProductRequestBody()
{
}
#JsonCreator
public ProductRequestBody(#NonNull #JsonProperty("name") String name,
#NonNull #JsonProperty("category") String category,
#NonNull #JsonProperty("cost") Double cost)
{
this.name = name;
this.category = category;
this.cost = cost;
}
#JsonProperty("description")
public String getDescription() {
return description;
}
}
In my spring boot project, I noticed a strange Jackson behavior. I searched over internet, found out what to do, but haven't found out why.
UserDto:
#Setter
#Getter
#AllArgsConstructor
public class UserDto {
private String username;
private String email;
private String password;
private String name;
private String surname;
private UserStatus status;
private byte[] avatar;
private ZonedDateTime created_at;
}
Adding a new user works just fine.
TagDto:
#Setter
#Getter
#AllArgsConstructor
public class TagDto {
private String tag;
}
Trying to add a new tag ends with an error:
com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of TagDto (although at least one Creator exists): cannot deserialize from Object value (no delegate- or property-based Creator)
The solution to the problem was to add zero-arg constructor to the TagDto class.
Why does Jackson require no-arg constructor for deserialization in TagDto, while working just fine with UserDto?
Used same method for adding both.
My Tag and User entities are both annotated with
#Entity
#Setter
#Getter
#NoArgsConstructor
and have all args constructors:
#Entity
#Setter
#Getter
#NoArgsConstructor
public class User extends AbstractModel {
private String username;
private String password;
private String email;
private String name;
private String surname;
private UserStatus status;
#Lob
private byte[] avatar;
#Setter(AccessLevel.NONE)
private ZonedDateTime created_at;
public User(final String username, final String password, final String email, final String name, final String surname) {
this.username = username;
this.password = password;
this.email = email;
this.name = name;
this.surname = surname;
this.created_at = ZonedDateTime.now();
}
}
#Entity
#Setter
#Getter
#NoArgsConstructor
#AllArgsConstructor
public class Tag extends AbstractModel {
private String tag;
}
#MappedSuperclass
#Getter
public abstract class AbstractModel {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
}
Entity generation:
#PostMapping(path = "/add")
public ResponseEntity<String> add(#Valid #RequestBody final D dto) {
this.abstractModelService.add(dto);
return new ResponseEntity<>("Success", HttpStatus.CREATED);
}
public void add(final D dto) {
//CRUD repository save method
this.modelRepositoryInterface.save(this.getModelFromDto(dto));
}
#Override
protected Tag getModelFromDto(final TagDto tagDto) {
return new Tag(tagDto.getTag());
}
#Override
protected User getModelFromDto(final UserDto userDto) {
return new User(userDto.getUsername(), userDto.getPassword(), userDto.getEmail(), userDto.getName(), userDto.getSurname());
}
Error occurs when parsing JSON
{"tag":"example"}
sent via postman localhost:8081/tag/add, returns
{
"timestamp": "2020-09-26T18:50:39.974+00:00",
"status": 400,
"error": "Bad Request",
"message": "",
"path": "/tag/add"
}
I am using Lombok v1.18.12 and Spring boot 2.3.3.RELEASE with Jackson v2.11.2.
TL;DR: Solution is at the end.
Jackson supports multiple ways of creating POJOs. The following lists the most common ways, but it likely not a complete list:
Create instance using no-arg constructor, then call setter methods to assign property values.
public class Foo {
private int id;
public int getId() { return this.id; }
#JsonProperty
public void setId(int id) { this.id = id; }
}
Specifying #JsonProperty is optional, but can be used to fine-tune the mappings, together with annotations like #JsonIgnore, #JsonAnyGetter, ...
Create instance using constructor with arguments.
public class Foo {
private int id;
#JsonCreator
public Foo(#JsonProperty("id") int id) {
this.id = id;
}
public int getId() {
return this.id;
}
}
Specifying #JsonCreator for the constructor is optional, but I believe it is required if there is more than one constructor. Specifying #JsonProperty for the parameters is optional, but is required for naming the properties if the parameter names are not included in the class file (-parameters compiler option).
The parameters imply that the properties are required. Optional properties can be set using setter methods.
Create instance using factory method.
public class Foo {
private int id;
#JsonCreator
public static Foo create(#JsonProperty("id") int id) {
return new Foo(id);
}
private Foo(int id) {
this.id = id;
}
public int getId() {
return this.id;
}
}
Create instance from text value using String constructor.
public class Foo {
private int id;
#JsonCreator
public Foo(String str) {
this.id = Integer.parseInt(id);
}
public int getId() {
return this.id;
}
#JsonValue
public String asJsonValue() {
return Integer.toString(this.id);
}
}
This is useful when a the POJO has a simply text representation, e.g. a LocalDate is a POJO with 3 properties (year, month, dayOfMonth), but is generally best serialized as a single string (yyyy-MM-dd format). #JsonValue identifies the method to be used during serialization, and #JsonCreator identifies the constructor/factory-method to be used during deserialization.
Note: This can also be used for single-value construction using JSON values other than String, but that is very rare.
Ok, that was the background information. What is happening for the examples in the question, it that UserDto works because there is only one constructor (so #JsonCreator is not needed), and many arguments (so #JsonProperty is not needed).
However, for TagDto there is only a single-argument constructor without any annotations, so Jackson classifies that constructor as a type #4 (from my list above), not a type #2.
Which means that it is expecting the POJO to be a value-class, where the JSON for the enclosing object would be { ..., "tag": "value", ... }, not { ..., "tag": {"tag": "example"}, ... }.
To resolve the issue, you need to tell Jackson that the constructor is a property initializing constructor (#2), not a value-type constructor (#4), by specifying #JsonProperty on the constructor argument.
This means that you cannot have Lombok create the constructor for you:
#Setter
#Getter
public class TagDto {
private String tag;
public TagDto(#JsonProperty("tag") String tag) {
this.tag = tag;
}
}
We have an Enum defined with Jackson annotation, "#JsonFormat(shape = JsonFormat.Shape.OBJECT)"
e.g.
package com.test;
import com.fasterxml.jackson.annotation.JsonFormat;
#JsonFormat(shape = JsonFormat.Shape.OBJECT)
public enum SampleEnumName {
OPTION_1 ("NAME_1", "DESCRIPTION_1", "CATEGORY_1"),
OPTION_2 ("NAME_2", "DESCRIPTION_2", "CATEGORY_2"),
OPTION_3 ("NAME_3", "DESCRIPTION_3", "CATEGORY_3");
private String name;
private String description;
private String category;
private SampleEnumName(String name, String description, String category) {
this.name = name;
this.description = description;
this.category = category;
}
public String getName() {
return name;
}
public String getDescription() {
return description;
}
public String getCategory() {
return category;
}
}
When its schema is generated we see it as an object, e.g.
{"type":"object","id":"urn:jsonschema:com:test:SampleEnumName","properties":{"name":{"type":"string"},"description":{"type":"string"},"category":{"type":"string"}}}
But for the same, when we check the JSON generated by swagger, the following is shown in schema:
{"type":"string","enum":["OPTION_1","OPTION_2","OPTION_3"]}
Is there a way (some swagger annotation equivalent of Jackson annotation "#JsonFormat(shape = JsonFormat.Shape.OBJECT)"), which can show Object definition of Enum?
We are using swagger 1.5.7
i got the same problem, updated to Swagger 2.9.2 and solved.
I want to load any property files in spring POJO classes.
Actually, I want to use any properties from property file in #Size, #NotNull or any validation annotations in spring model classes.
But the issue is that #Size, #NotNull etc annotation are invoked at compile-time whereas any property file's data are invoked at runtime.
Even, I want to use in the max parameter of #Size which accepts the only constant integer. How can I load value and cast it to Integer as a constant value?
And I can use custom validator or any custom annotation to solve the issue but as per the organization policy, I can't use much customization.
I found an additional solution to this problem that we can use a class of constants instead of the property file.
I can use this constants file anywhere in my workspace whereas property file can't use at Size.max property of the model validation
CommonConstants.java
public class CommonConstants
{
public static final int NAME=4;
public static final int ROLE=2;
}
Employee.java
private int id;
#Size(max = CommonConstants.NAME, message = "length exceeds : name")
private String name;
#Size(max = CommonConstants.ROLE, message = "length exceeds : role")
private String role;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getRole() {
return role;
}
public void setRole(String role) {
this.role = role;
}
EmployeeController.java
#Controller
public class EmployeeController {
private static final Logger logger = LoggerFactory.getLogger(EmployeeController.class);
private Map<Integer, Employee> emps = null;
public EmployeeController() {
emps = new HashMap<Integer, Employee>();
}
#RequestMapping(value = "/emp/save.do", method = RequestMethod.POST)
public String saveEmployeeAction(#Valid Employee employee, BindingResult bindingResult, Model model)
{
if (bindingResult.hasErrors()) {
logger.info("Returning empSave.jsp page");
return "empSave";
}
logger.info("Returning empSaveSuccess.jsp page");
model.addAttribute("emp", employee);
emps.put(employee.getId(), employee);
return "empSaveSuccess";
}
}
Output
I had the following entity mapped using JPA 2:
#Entity
public class Translation {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "id")
private Long id;
private String locale;
#Column(name = "business_code",insertable = true,updatable = false,length = 200,nullable = false)
private String code;
private String text;
// Gettets and setters
....
}
Then I realized than the pair (locale,code) should be unique, so I have changed the entity to have an embeddedId composed by locale, code and I removed the column id from the mapping. This way this pair would act as primary key and they could not be repeated:
As a result:
#Entity
public class Translation {
#EmbeddedId
private TranslationId translationId;
private String text;
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public TranslationId getTranslationId() {
return translationId;
}
public void setTranslationId(TranslationId translationId) {
this.translationId = translationId;
}
#Override
public boolean equals(Object obj) {
return EqualsBuilder.reflectionEquals(this, obj);
}
#Override
public int hashCode() {
return HashCodeBuilder.reflectionHashCode(this);
}
}
And the embeddedId class:
#Embeddable
public class TranslationId implements Serializable{
private static final long serialVersionUID = 1L;
private String locale;
#Column(name = "business_code",insertable = true,updatable = false,length = 200,nullable = false)
private String code;
#Override
public boolean equals(Object obj){
return EqualsBuilder.reflectionEquals(this, obj);
}
#Override
public int hashCode(){
return HashCodeBuilder.reflectionHashCode(this);
}
public String getLocale() {
return locale;
}
public void setLocale(String locale) {
this.locale = locale;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
}
I'm using Spring data to query the data, so I have modified also my JPA repository to take in account the new composite Id:
#Repository
public interface TranslationRepository extends JpaRepository<Translation,TranslationId> {
}
So, first of all, does anyone see anything wrong here? Should I do it in another way? As my tests are not passing anymore, if I do a simple translationRepository.findAll(), I'm not getting any result (however there is data in the db), but I'm not getting any error message...
And second - if I get this to work, and then I want Spring data to query all the translations only by locale (not by code), how can I do it? As locale and code are now part of the primary key, can I query them independently?
Since your first problem was already fixed, I'll answer the second question
I want Spring data to query all the translations only by locale (not by code), how can I do it?
locale is still accessible as a single property via translationId. In JPQL you can write
SELECT t FROM Translation t WHERE t.translationId.locale = :locale
In Spring Data repository you can either use the #Query on a custom-named method
#Query("SELECT t FROM Translation t WHERE t.translationId.locale = :locale")
public List<Translation> findByLocale(#Param("locale") String locale)
or go with the slightly longer method name, but automatically handled by Spring Data
public List<Translation> findByTranslationIdLocale(String locale)