Modelmapper to convert from String to LocalDate

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

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