Converting BigDecimal differs Scale

[acemint]

I'm trying to convert a data with a generic Object as follow

{"amount":100000000.23,"taxAmount":11000000.0}

But for some reason, the StringCache for the BigDecimal differs. One uses an exponent while the others don't. As a result, when using .toString to this class, it returns

{"amount":100000000.23,"taxAmount":1.1E7}

Any idea why this happens? Thanks

[cowtowncoder]

Please provide a bit of code to make sure we know what you mean. I am guessing "generic Object" means that you are doing something like:

Object value = objectMapper.readValue(json, Object.class);

but are you configuring mapper in any way? Enabling DeserializationFeature.USE_BIG_DECIMAL_FOR_FLOATS maybe? (by default, FP values are read as Doubles)

[acemint]

Yes I'm using your code above and I've enabled DeserializationFeature.USE_BIG_DECIMAL_FOR_FLOATS. Both data types as shown have been converted as BigDecimal. However, the stringCache property for BigDecimal differs if the trailing decimal is 0

[acemint]

I guess I need to clarify my question:

I'd like to set the scale of the BigDecimal which is converted from the JsonDeserializer, because I do not want exponent symbol to appear in the BigDecimal, is there such a way to do that?

[cowtowncoder]

@acemint There is no out-of-the-box option for post-processing BigDecimal. You may want to add custom deserializer to do that.

However: for JSON serialization side there is:

JsonGenerator.Feature.WRITE_BIGDECIMAL_AS_PLAIN

enabling of which (applied via JsonFactory) will force non-scientific notation for BigDecimal values written out.
So depending on your exact needs that might work.

[acemint]

Found similar issue here
#632

[acemint]

Reopened this discussion as with version 2.14.2 I still found the precision to be different according to the value passed, is it expected?

[cowtowncoder]

To be pedantic, I don't think precision is different, just notation. Actual value is not changed. I suspect it is JDK itself that changes representation, however (BigDecimal constructor)?

[cowtowncoder]

One thing to check is to see how basic new BigDecimal("100000000.23") (etc) works -- I think that will produce values you see, and Jackson doesn't really do anything special on read/deserialization side.
If so, I'd probably close this discussion: if there is something you would like Jackson to do, that'd be additional feature, but not anything that can be fixed per se (this may seem like a tiny distinction but it matters wrt version compatibility at least).