小编use*_*278的帖子

如何解决这个问题:tfidf是我的主类为什么运行jar文件后会出现这个错误？

java.lang.RuntimeException: java.lang.NoSuchMethodException: tfidf$Reduce.<init>()
    at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:115)
    at org.apache.hadoop.mapred.Task$OldCombinerRunner.combine(Task.java:1423)
    at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.sortAndSpill(MapTask.java:1436)
    at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.flush(MapTask.java:1298)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:437)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:372)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:396)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
    at org.apache.hadoop.mapred.Child.main(Child.java:249)
 Caused by: java.lang.NoSuchMethodException: tfidf$Reduce.<init>()
    at java.lang.Class.getConstructor0(Class.java:2715)
    at java.lang.Class.getDeclaredConstructor(Class.java:1987)
    at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:109)
    ... 10 more

我需要在mapreduce程序中使用全局变量,如何在下面的代码中设置它并在reducer中使用全局变量.

public class tfidf
{
  public static tfidfMap..............
  {
  }
  public static tfidfReduce.............
  {
  }
  public static void main(String args[])
  {
       Configuration conf=new Configuration();
       conf.set("","");
  } 

}