如何解决这个问题:tfidf是我的主要课程 运行jar文件后出现此错误的原因?
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
答案 0 :(得分:8)
我认为它试图实例化一个减速器。将reducer类声明为static并尝试。