[QUESTION] fastjson1.x和fastjson2.x对字段注解上JSONWriter.Feature.WriteNullNumberAsZero行为不一致，如何兼容？

[huisman6]

请描述您的问题

我们应用fastjson1.x升级为fastjson2.x之后，字段注解上的serializeFeatures = JSONWriter.Feature.WriteNullNumberAsZero 失效了，原先fastjson1.x 会正确将所有Number为null时返回0。

当通过 JSON.toJSONString(new NumberDTO(),JSONWriter.Feature.WriteNullNumberAsZero)，所有Number为null时会正确返回0；

当通过：JSON.toJSONString(new NumberDTO()) ，即使加了注解，也只有Integer类型的输出0。

请问如何使字段注解上的Feature生效？

@DaTa
public class NumberDTO implements Serializable {
@JSONField(serializeFeatures = JSONWriter.Feature.WriteNullNumberAsZero)
private BigDecimal bigDecimal;
@JSONField(serializeFeatures = JSONWriter.Feature.WriteNullNumberAsZero)
private Integer integer;
@JSONField(serializeFeatures = JSONWriter.Feature.WriteNullNumberAsZero)
private Double wrapperDouble;
@JSONField(serializeFeatures = JSONWriter.Feature.WriteNullNumberAsZero)
private Float wrapperFloat;
@JSONField(serializeFeatures = JSONWriter.Feature.WriteNullNumberAsZero)
private Long wrapperLong;
@JSONField(serializeFeatures = JSONWriter.Feature.WriteNullNumberAsZero)
private Byte byteValue;
@JSONField(serializeFeatures = JSONWriter.Feature.WriteNullNumberAsZero)
private Short wrapperShort;
@JSONField(serializeFeatures = JSONWriter.Feature.WriteNullNumberAsZero)
private BigInteger bigInteger;
@JSONField(serializeFeatures = JSONWriter.Feature.WriteNullNumberAsZero)
private Number number;
}

[jujn]

应该是 bug，我去看一下

[mymde]

  // if (!jw.isWriteNulls())
        if ((features & JSONWriter.Feature.WriteNulls.mask) == 0) {
            long nullFeatures = JSONWriter.Feature.WriteNulls.mask;
            if (fieldClass == AtomicLongArray.class
                    || fieldClass == AtomicIntegerArray.class
                    || Collection.class.isAssignableFrom(fieldClass)
                    || fieldClass.isArray()) {
                nullFeatures |= WriteNullListAsEmpty.mask;
                nullFeatures |= NullAsDefaultValue.mask;
            } else if (Number.class.isAssignableFrom(fieldClass)) {
                nullFeatures |= WriteNullNumberAsZero.mask;
                nullFeatures |= NullAsDefaultValue.mask;
            } else if (fieldClass == Boolean.class) {
                nullFeatures |= WriteNullBooleanAsFalse.mask;
                nullFeatures |= NullAsDefaultValue.mask;
            } else if (fieldClass == String.class) {
                nullFeatures |= WriteNullStringAsEmpty.mask;
                nullFeatures |= NullAsDefaultValue.mask;
            } else {
                nullFeatures |= NullAsDefaultValue.mask;
            }
            mwc.genIsEnabled(nullFeatures, notNull_);
//            mw.iload(mwc.var(WRITE_NULLS));
//            mw.ifeq(notNull_);
        }

可能是 mwc.genIsEnabled(nullFeatures, notNull_); 这块的问题，导致跳转其他分支，没有执行writeNumberNull和writeDecimalNull

[wenshao]

https://github.com/alibaba/fastjson2/releases/tag/2.0.59
问题已修复，请用新版本