java.lang.RuntimeException: java.lang.NoSuchMethodException:

最新推荐文章于 2023-12-05 16:06:13 发布

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最新推荐文章于 2023-12-05 16:06:13 发布

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文章标签： java 大数据

原文链接：http://www.cnblogs.com/luolizhi/p/5059083.html

本文探讨了在使用Hadoop时遇到的'NoSuchMethodException'错误，特别是针对内部类实例化的问题，并提供了解决方案：确保类为静态或正确声明非静态内部类。文章深入分析了错误产生的原因及解决步骤。

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[java] 15/12/19 14:09:46 INFO mapred.JobClient: Task Id : attempt_201512182036_0017_m_000000_0, Status : FAILED
[java] java.lang.RuntimeException: java.lang.NoSuchMethodException: org.lukey.hadoop.tianyi.TianYiBigData$MyMapper.<init>()
[java] at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:115)
[java] at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:719)
[java] at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
[java] at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
[java] at java.security.AccessController.doPrivileged(Native Method)
[java] at javax.security.auth.Subject.doAs(Subject.java:422)
[java] at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
[java] at org.apache.hadoop.mapred.Child.main(Child.java:249)
[java] Caused by: java.lang.NoSuchMethodException: org.lukey.hadoop.tianyi.TianYiBigData$MyMapper.<init>()
[java] at java.lang.Class.getConstructor0(Class.java:3082)
[java] at java.lang.Class.getDeclaredConstructor(Class.java:2178)
[java] at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:109)
[java] ... 7 more

需要在MyMapper前面加static。

If the class is an inner class, make sure it's declared static (i.e. doesn't need an instance of the enclosing class). Otherwise, Hadoop cannot instantiate your inner class and will give this same error - that a zero-arg constructor is needed.

http://stackoverflow.com/questions/11446635/no-such-method-exception-hadoop-init

转载于:https://www.cnblogs.com/luolizhi/p/5059083.html