Type Conversion

By default, formatters for various number and date types are installed, along with support for customization via @NumberFormat and @DateTimeFormat on fields.

To register custom formatters and converters, use the following:

@Configuration
public class WebConfiguration implements WebMvcConfigurer {

  @Override
  public void addFormatters(FormatterRegistry registry) {
    // ...
  }
}

By default Web MVC considers the request Locale when parsing and formatting date values. This works for forms where dates are represented as Strings with "input" form fields. For "date" and "time" form fields, however, browsers use a fixed format defined in the HTML spec. For such cases date and time formatting can be customized as follows:

@Configuration
public class DateTimeWebConfiguration implements WebMvcConfigurer {

  @Override
  public void addFormatters(FormatterRegistry registry) {
    DateTimeFormatterRegistrar registrar = new DateTimeFormatterRegistrar();
    registrar.setUseIsoFormat(true);
    registrar.registerFormatters(registry);
  }
}

See the FormatterRegistrar SPI and the FormattingConversionServiceFactoryBean for more information on when to use FormatterRegistrar implementations.