The mapper trapped in the gap tapped the tap wrapper with strap.
In this mapper file, we add a section to define the mapping of parameter values.
What kind of mapper will we need to bridge the data structures representing the business processes interfaces?
在现实情况中,我们的表达方式可能会更紧凑一些,我们的mapper会使用一个size方法的方法引用,以及整数的求和会用到一个预先定义的reducer。