Java to Jackson JSON serialization: Money fields

Question

Currently, I'm using Jackson to send out JSON results from my Spring-based web application.

The problem I'm having is trying to get all money fields to output with 2 decimal places. I wasn't able to solve this problem using setScale(2), as numbers like 25.50 are truncated to 25.5 etc

Has anyone else dealt with this problem? I was thinking about making a Money class with a custom Jackson serializer... can you make a custom serializer for a field variable? You probably can... But even still, how could I get my customer serializer to add the number as a number with 2 decimal places?

Answer 1

You can use a custom serializer at your money field. Here's an example with a MoneyBean. The field amount gets annotated with @JsonSerialize(using=...).

public class MoneyBean {     //...      @JsonProperty("amountOfMoney")     @JsonSerialize(using = MoneySerializer.class)     private BigDecimal amount;      //getters/setters... }  public class MoneySerializer extends JsonSerializer<BigDecimal> {     @Override     public void serialize(BigDecimal value, JsonGenerator jgen, SerializerProvider provider) throws IOException,             JsonProcessingException {         // put your desired money style here         jgen.writeString(value.setScale(2, BigDecimal.ROUND_HALF_UP).toString());     } } 

That's it. A BigDecimal is now printed in the right way. I used a simple testcase to show it:

@Test public void jsonSerializationTest() throws Exception {      MoneyBean m = new MoneyBean();      m.setAmount(new BigDecimal("20.3"));       ObjectMapper mapper = new ObjectMapper();      assertEquals("{\"amountOfMoney\":\"20.30\"}", mapper.writeValueAsString(m)); } 

Answer 2

You can use @JsonFormat annotation with shape as STRING on your BigDecimal variables. Refer below:

 import com.fasterxml.jackson.annotation.JsonFormat;    class YourObjectClass {        @JsonFormat(shape=JsonFormat.Shape.STRING)       private BigDecimal yourVariable;   }