map方法获得文件夹下文件名称

setup方法即为Mapper初始化的方法，可以点击Mapper按F3进行源码查看

static class MyMapper extends Mapper<Object,Object,Text,Text>{

protected void setup(Context context) throws IOException, InterruptedException{
FileSplit fs = (FileSplit) context.getInputSplit();
String k = fs.getPath().getName();
System.out.println(k);
}

protected void map(Object key, Object value, Context context) throws IOException, InterruptedException{

}
}