Spring Framework - Converter Examples

import org.springframework.core.convert.converter.Converter;

public class TradeIdToTradeConverter implements Converter<String, Trade> {

    private TradeService tradeService;

    public TradeIdToTradeConverter (TradeService tradeService) {
        this.tradeService = tradeService;
    }

    @Override
    public Trade convert (String id) {
        try {
            Long tradeId = Long.valueOf(id);
            return tradeService.getTradeById(tradeId);
        } catch (NumberFormatException e) {
            return null;
        }
    }

package com.logicbig.example;


import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class CustomConverterExample {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new
                AnnotationConfigApplicationContext(
                Config.class);

        ClientBean clientBean = context.getBean(ClientBean.class);
        clientBean.showLocalDateTime();
    }

}

package com.logicbig.example;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.convert.ConversionService;
import java.time.LocalDate;

public class ClientBean {
    private final String date;
    @Autowired
    private ConversionService conversionService;

    ClientBean(String date) {
        this.date = date;
    }

    public void showLocalDateTime() {
        LocalDate localDate = conversionService.convert(date, LocalDate.class);
        System.out.println(localDate);
    }
}

package com.logicbig.example;

import org.springframework.core.convert.converter.Converter;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

public class StringToLocalDateConverter
        implements Converter<String, LocalDate> {
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy/MM/dd");

    @Override
    public LocalDate convert(String dateTimeString) {
        return LocalDate.parse(dateTimeString, formatter);
    }
}

package com.logicbig.example;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.support.DefaultConversionService;

@Configuration
public class Config {
    @Bean
    public ConversionService conversionService() {
        DefaultConversionService service = new DefaultConversionService();
        service.addConverter(new StringToLocalDateConverter());
        return service;
    }

    @Bean
    public ClientBean clientBean() {
        return new ClientBean("2010/10/05");
    }
}