I have two bean classes like below
package com.abc;
public class Employee{
private String id;
private String name;
//setters & getters
}
and
package com.cda;
public class EmployeeDTO{
private String id;
private String name;
//setters & getters
}
I want to set the property fields from Employee to EmployeeDTO using spring xml configuration. Where data is coming from some other sources to the Employee Object.
Can you please help me on this scenario.
Use BeanUtils from apache or spring framework instead. Be careful about the argument positioning in these two ways. They are exactly opposite:
org.apache.commons.beanutils.BeanUtils.copyProperties(Object dest, Object orig)
OR
org.springframework.beans.BeanUtils.copyProperties(Object source, Object target)
this is actually not a task that spring does for you. Spring is more about wiring all depending objects together that work together during runtime. What you need is a mapper like mapstruct or enter link description here.
Lets consider a scenario
Where Employee gets it data from a datasource and now you want to map it to EmployeeDto
In such cases:
You can add a constructor in EmployeeDto which takes Employee as parameter and maps the field
You can use ModelMapper where a simple line like:EmployeeDto employeeDto = modelMapper.map(employee, EmployeeDto.class); will work
Use BeanUtils import org.apache.commons.beanutils.BeanUtils;
EmployeeDto newObject = new EmployeeDto();
BeanUtils.copyProperties(newObject, oldObject); reference
Use Jackson ObjectMapper by the convertValue() method: (not recommended due to performance issues)
ObjectMapper mapper = new ObjectMapper();
Employee employee = ...;
EmployeeDto employeeDto = mapper.convertValue(employee, EmployeeDto.class);
Related
In a Spring Boot application, Spring Boot is used to build a Properties object from a YAML file as follows:
YamlPropertiesFactoryBean yamlFactory = new YamlPropertiesFactoryBean();
yamlFactory.setResources(new DefaultResourceLoader().getResource("application.yml"));
Properties properties = yamlFactory.getObject();
The reason why Spring Boot's own parser is used is that it not only reads YAML-compliant settings, but also dot-notated properties like e.g:
artist.elvis.name: "Elvis"
artist.elvis.message: "Aloha from Hawaii"
Now that the Properties object is built, I want to map it into an object like the following for example:
#JsonIgnoreProperties(ignoreUnknown = true)
private record Artist(Elvis elvis) {
private record Elvis(String name, String message) { }
}
My question is:
How can this be done with Jackson? Or is there another/better solution for this?
Many thanks for any help
I saw functionality like that in Ratpack framework.
e.g.:
var propsFileUrl =
Thread.currentThread()
.getContextClassLoader()
.getResource("application.properties");
ApplicationProperties applicationProperties =
ConfigData.builder()
.props(propsFileUrl)
.build()
.get(ApplicationProperties.class);
under the hood it is indeed done by using jackson's object mapper, but the logic is not as trivial to post it here.
here's the library:
https://mvnrepository.com/artifact/io.ratpack/ratpack-core/2.0.0-rc-1
application.yml is the default yml file, so no custom configuration is required. Value annotation should be able to read the properties.
#Value("${artist.elvis.name}")
private String name;
Next part I am not sure about your requirements, but hope this is what you are looking for.
To bind to this object 'constructor' can be a good option.
Class for elvis
#Bean
public class Elvis {
private String name;
private String message;
public Elvis(#Value("${artist.elvis.name"}) final String name, #Value("${artist.elvis.message"}) final String message) {
this.name=name;
this.message=message
}
// getter setter for name and message
}
Now Autowire the created bean to Artist bean
#Bean("artists")
public class Artists {
#Autowired
private Elvis elvis
pubic Elvis getElvis() {
return elvis;
}
}
I have a strange problem with model mapper. Probably I missunderstand how it works.
What I have: an example Model class:
class Model{
String name;
String surname;
Integer age;
...and much much more
And a method
private void foo(){
ModelMapper modelMapper = new ModelMapper();
Model model = Model.builder().name("foo").surname("bar").age(23).build();
Model newModel = Model.builder().name("john").build();
modelMapper.map(newModel, model);
System.out.println(model.toString());
}
And the output is: Model(name=john, surname=null, age=null)
But what I expect Model(name=john, surname=bar, age=23)
Can I do this using model mapper? If not, how to do this easily (i dont want update manually each property)? Thanks.
You can do it easily using Lombok builder #Builder.Default You just need to update your Model class
public class Model {
#Builder.Default
String name = "foo";
#Builder.Default
String surname = "bar";
#Builder.Default
Integer age = 23;
Yes you misunderstood how it works : it works well in your case. It is mapping null values too. If you do not want that, you can use that code inside a Spring Configuration class dedicated to ModelMapper :
#Bean
public ModelMapper modelMapper() {
ModelMapper modelMapper = new ModelMapper();
modelMapper.getConfiguration()
.setFieldAccessLevel(Configuration.AccessLevel.PRIVATE)
.setMatchingStrategy(MatchingStrategies.STANDARD)
.setSkipNullEnabled(true);
return modelMapper;
}
The important part is setSkipNullEnabled(true) which handle that globally here. Take care of that when you are handling forms.
I have a springboot application which is hitting raw api's of the datasource. Now suppose I have a Customer entity with approx 50 fields and I have a raw api for it in which I pass names of the columns and I get the values for that column. Now I am implementing api in springboot which consumes raw api.
I need to implement different api's in springboot for different combinations of the fields of Customer entity and return only those fields setted in object for which user had queried and remove the null valued fields from the object. One way is to implement different dto's for different combinations of the columns of Customer entity. Is there any other way to implement the same in which I don't need to define different dto's for different combinations of the columns of Customer entity in Spring boot ???
You can configure the ObjectMapper directly, or make use of the #JsonInclude annotation:
mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
OR
#JsonInclude(JsonInclude.Include.NON_NULL)
#JsonInclude(JsonInclude.Include.NON_NULL)
public class Customer {
private Long id;
private String name;
private String email;
private String password;
public Customer() {
}
// getter/setter ..
}
You can see how to do it with this sample code:
Customer customer = new Customer();
customer.setId(1L);
customer.setName("Vikas");
customer.setEmail("info#vikas.com");
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
String valueAsString = objectMapper.writeValueAsString(customer);
Since the password is left null, you will have an object that does not exist password.
{
"id": 1,
"name": "Vikas",
"email": "info#vikas.com"
}
with Jackson 2.0 serialization you can specify data inclusion on non nulls at different levels, i.e. on the object mapper (with constructor options), the DTO class or DTO class fields (with annotations).
See Jackson annotations here
This can be done using #JsonInclude inside the DTO class. Please refer following code block for ignoring null values.
#JsonInclude(Include.NON_NULL) // ignoring null values
#Data //lombock
#Builder //builder pattern
public class Customer {
private Long id;
private String name;
private String email;
private String password;
}
With jackson there is a way to ignore some fields using #JsonIgnore. Is there a way to do the opposite, and only show fields with are annotated? I'm working with an external class with a lot of fields and I only want to select a small subset of them. I'm getting tons of recursion problems (using some type of ORM) where object A -> B -> A -> B -> A .... which are not even necessary to export.
You can configure the object mapper to ignore absolutely everything unless specified by JsonProperty,
public class JacksonConfig {
public static ObjectMapper getObjectMapper(){
//The marshaller
ObjectMapper marshaller = new ObjectMapper();
//Make it ignore all fields unless we specify them
marshaller.setVisibility(
new VisibilityChecker.Std(
JsonAutoDetect.Visibility.NONE,
JsonAutoDetect.Visibility.NONE,
JsonAutoDetect.Visibility.NONE,
JsonAutoDetect.Visibility.NONE,
JsonAutoDetect.Visibility.NONE
)
);
//Allow empty objects
marshaller.configure( SerializationFeature.FAIL_ON_EMPTY_BEANS, false );
return marshaller;
}
}
public class MyObject {
private int id;
#JsonProperty
private String name;
private Date date;
//Getters Setters omitted
in this case only name would be serialized.
Sample repo, https://github.com/DarrenForsythe/jackson-ignore-everything
Yes definitely you can; Create a class with only the feilds you need and add the below property in the object mapper and rest is done.
DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES to false
You can use #JsonIgnoreProperties(ignoreUnknown=true) on the pojo class so only the fields which are available in the pojo class will be mapped and resf will be left out.
For example
Json data
{
"name":"Abhishek",
"age":30,
"city":"Banglore",
"state":"Karnatak"
}
pojo class
#JsonIgnoreProperties(ignoreUnknown=true)
Class Person{
private int id;
private String name;
private String city;
}
Here state in not present in the Person class so that field won't be mapped
I can not use #jsonIgnore as I need the value of the new property to be used at multiple places in the application.
Tried to define the custom deserialiser but no success not sure if I am doing it right. For example my class looks like below
old class :
Employee {
Long id;
String name;
}
new class:
Employee {
Long id;
String name;
String dept= "IT";
}
Use #JsonInclude(Include.NON_NULL) annotation for the POJO. In earlier versions of Jackson (1.x), you may have to use #JsonSerialize(include=JsonSerialize.Inclusion.NON_NULL)
Also, you'll have to use the wrapper class instead of the primitive (Long instead of long), which always has a value as null if nothing is assigned.