java推土机5.3.2。以编程方式设置自定义转换器？

Question

如何以编程方式设置推土机的自定义转换器？以下代码不起作用：

自定义转换器实现：

class ConverterImpl extends DozerConverter<A, B> {

ConverterImpl() {
    super(A.class, B.class);
}

@Override
public B convertTo(A source, B destination) {
    return destination;
}

@Override
public A convertFrom(B source, A destination) {
    return destination;
}
}

测试代码：

DozerBeanMapper mapper = new DozerBeanMapper();
mapper.setCustomConverters(Collections.<CustomConverter>singletonList(new ConverterImpl()));
A a = new A(); 
B b = mapper.map(a, A.class);  

运行上述代码后，不会调用自定义转换器。怎么了