HDFS客户端新建maven工程时，运行程序出现以下问题，Collections包已经有了，为什么还是报错呢？

Question

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/collections/map/UnmodifiableMap
at org.apache.hadoop.conf.Configuration$DeprecationContext.(Configuration.java:409)
at org.apache.hadoop.conf.Configuration.(Configuration.java:448)
at com.wqd.hdfs.HDFSClient.main(HDFSClient.java:11)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.collections.map.UnmodifiableMap
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

Answer 1

跪求大神指点一下啊！

Answer 2

你把org/apache/commons/collections/map/路径下的都删了在重新加载maven试试

Answer 3

添加commons-collections-3.2.2.jar到项目中去