java - Hadoop. How to get Job from Mapper -

i'm new in hadoop. time i'm realising word counter inputted keyword. read using job class better jobconf. have code main class:

 ... configuration conf = new configuration(); conf.set("keyword", args[0]); job job = new job(conf); ... 

so how can keyword in mapper back? understand need job object , job configuration object using getconfiguration() method , call get("keyword") method.

but how need job mapper class?

thank's time.

when map called on mapper implementation passed context object exposes getconfiguration method. give want.