Modelmapper to convert from String to LocalDate - spring

Question

My DTO is having date field in String format. My entity is having date as LocalDate. Currently I am skipping it from map and then later manually explicitly setting it (String to Date and vis-versa).
is it possible to convert it automatically? I tried Converter inside spring bean but it gives me lot of compile errors (type Converter does not take parameters, does not override convert method - also lot of error for convert() as well).
#Bean
public ModelMapper studentModelMapper() {
....
Converter<String, LocalDate> toStringDate = new AbstractConverter<String, LocalDate>() {
protected String convert(String source) {
return source == null ? null : new LocalDate(source);
}
};
....
}
I am not very familiar with modelmapper. Any help is greatly appreciated.
As suggested I tried with LocalDate for DTO but the problem is when I send this entity at front (REST call) I get following JSON.
"dateOfBirth": {
"year": 1972,
"month": "JANUARY",
"monthValue": 1,
"dayOfMonth": 4,
"dayOfWeek": "TUESDAY",
"era": "CE",
"dayOfYear": 4,
"leapYear": true,
"chronology": {
"id": "ISO",
"calendarType": "iso8601"
}
}
My front end developer need "YYYY-MM-DD".

Answer 1

If you want to convert to LocalDate you need to create a Provider otherwise ModelMappercannot instantiate LocalDate because it doesn't have a public default constructor.
Use this configuration and it will work:
ModelMapper modelmapper = new ModelMapper();
Provider<LocalDate> localDateProvider = new AbstractProvider<LocalDate>() {
#Override
public LocalDate get() {
return LocalDate.now();
}
};
Converter<String, LocalDate> toStringDate = new AbstractConverter<String, LocalDate>() {
#Override
protected LocalDate convert(String source) {
DateTimeFormatter format = DateTimeFormatter.ofPattern("yyyy-MM-dd");
LocalDate localDate = LocalDate.parse(source, format);
return localDate;
}
};
modelmapper.createTypeMap(String.class, LocalDate.class);
modelmapper.addConverter(toStringDate);
modelmapper.getTypeMap(String.class, LocalDate.class).setProvider(localDateProvider);
Test output:
String dateTest = "2000-09-27";
LocalDate dateConverted = modelmapper.map(dateTest, LocalDate.class);
System.out.println(dateConverted.toString()); //Output = 2000-09-27

Answer 2

I also use ModelMapper 2.3.5 for my project and had a similar issue.
The use of the ModelMapper related project https://github.com/modelmapper/modelmapper-module-java8/ helped me a lot.
It provides two modules that one can add to ModelMapper configuration by providing the following maven dependencies to your project :
<!-- https://mvnrepository.com/artifact/com.github.chhsiao90/modelmapper-module-java8-datatypes -->
<dependency>
<groupId>com.github.chhsiao90</groupId>
<artifactId>modelmapper-module-java8-datatypes</artifactId>
<version>1.1.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.github.chhsiao90/modelmapper-module-jsr310 -->
<dependency>
<groupId>com.github.chhsiao90</groupId>
<artifactId>modelmapper-module-jsr310</artifactId>
<version>1.1.0</version>
</dependency>
Then the ModelMapper configuration should add
modelMapper.registerModule(new Jsr310Module());
modelMapper.registerModule(new Jdk8Module());
Hope this can help

Answer 3

I am currently using ModelMapper 2.3.5 and the accepted solution does not work with me when I do ModelMapper.validate() for my mapping. See my related question.
I managed to get also validation working - surprisingly - by removing provider totally so only converter is used. So like:
modelmapper.addConverter(toStringDate);
modelmapper.getTypeMap(String.class, LocalDate.class); // no provider, maps ok with me still
modelmapper.validate();