您可以使用configuration类来设置和获取自定义配置属性，如下所示：
在您的驱动程序代码中：

import org.apache.hadoop.conf.Configuration;
// other imports ignored for brevity
// ...

public class YourDriver extends Configured implements Tool {
  public int run(String[] args) {
    Configuration conf = getConf();
    conf.set("yourcustom.property", args[2]);
    // other driver code ignored
    // ...
  }

  public static void main(String[] args)  {
    int res = ToolRunner.run(new Configuration(), new YourDriver(), args);
    System.exit(res);
  }
}

从Map器代码：

public class YourMapper extends Mapper<...> {
  private String yourArgument;

  @Override
    protected void setup(Context context) {
        Configuration c = context.getConfiguration();
        yourArgument = c.get("yourcustom.property");
    }

  @Override
  protected void map(...) {
    // use your argument
  }
}