I wrote Currency Converter program that reads JSON
from api.fixer.io
, maps object and creates simple data set of selected rates. My program was doing its job well until I stopped using Jackson
to parse and map object and replaced it with RestTemplate
. It reads base currency and date well, but not Rates
subobject. Why?
My Code: Currency
class:
package com.github.gromo13.currencyConverter.model.util;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@JsonIgnoreProperties(ignoreUnknown = true)
public class Currency {
private String base;
private String date;
private Rates rates;
public Currency() {
}
public String getBase() {
return this.base;
}
public void setBase(String base) {
this.base = base;
}
public String getDate() {
return this.date;
}
public void setDate(String date) {
this.date = date;
}
public Rates getRates() {
return this.rates;
}
public void setRates(Rates rates) {
this.rates = rates;
}
public double getRate(String currencyCode) {
return rates.getRate(currencyCode);
}
}
Rates
class:
package com.github.gromo13.currencyConverter.model.util;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@JsonIgnoreProperties(ignoreUnknown = true)
public class Rates {
private double eur;
private double pln;
private double usd;
public double getEur() {
return this.eur;
}
public void setEur(double eur) {
this.eur = eur;
}
public double getPln() {
return this.pln;
}
public void setPln(double pln) {
this.pln = pln;
}
public double getUsd() {
return this.usd;
}
public void setUsd(double usd) {
this.usd = usd;
}
public double getRate(String currencyCode) {
currencyCode = currencyCode.toUpperCase();
switch (currencyCode) {
case "EUR":
return this.eur;
case "PLN":
return this.pln;
case "USD":
return this.usd;
default:
return 1;
}
}
}
Repository
class that have to map Currency
object using RestTemplate
:
package com.github.gromo13.currencyConverter.repository;
import com.github.gromo13.currencyConverter.model.util.Currency;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import org.springframework.web.client.RestTemplate;
@Repository
public class FixerIoCurrencyRepository implements CurrencyRepository {
@Autowired
private RestTemplate restTemplate;
public void setRestTemplate(RestTemplate restTemplate) {
this.restTemplate = restTemplate;
}
@Override
public Currency getCurrency(String currencyCode) {
Currency currency = restTemplate.getForObject("http://api.fixer.io/latest?base={currencyCode}", Currency.class, currencyCode);
return currency;
}
}
Sample JSON data I am trying to parse and map
I am using this Currency
object to prepare DataSet
object with a simple map of <currencyName, rate>
and print it in a table in view. Everything works fine, I just receive every time 0
as the rate in each currency.
The problem is that in Rates
class properties are lower case and in JSON data upper case.
You can define in a @Configuration
class your RestTemplate
to use an ObjectMapper
accepting case insensitive properties. That way, you don't have to change the format of Rates
properties.
@Bean
public ObjectMapper objectMapper() {
ObjectMapper mapper = new ObjectMapper();
mapper.configure(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES, true);
return mapper;
}
@Bean
public MappingJackson2HttpMessageConverter mappingJacksonHttpMessageConverter() {
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
converter.setObjectMapper(objectMapper());
return converter;
}
@Bean
public RestTemplate restTemplate() {
RestTemplate restTemplate = new RestTemplate();
restTemplate.getMessageConverters().add(0, mappingJacksonHttpMessageConverter());
return restTemplate;
}
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