java.lang.ClassNotFoundException: org.apache.hadoop.fs.CanUnbuffer

log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).log4j:WARN Please initialize the log4j system properly.log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/fs/CanUnbufferat java.lang.ClassLoader.defineClass1(Native Method)at java.lang.ClassLoader.defineClass(ClassLoader.java:760)at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)at java.net.URLClassLoader.defineClass(URLClassLoader.java:455)at java.net.URLClassLoader.access$100(URLClassLoader.java:73)at java.net.URLClassLoader$1.run(URLClassLoader.java:367)at java.net.URLClassLoader$1.run(URLClassLoader.java:361)at java.security.AccessController.doPrivileged(Native Method)at java.net.URLClassLoader.findClass(URLClassLoader.java:360)at java.lang.ClassLoader.loadClass(ClassLoader.java:424)at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)at java.lang.ClassLoader.loadClass(ClassLoader.java:357)at org.apache.hadoop.hdfs.DistributedFileSystem.initialize(DistributedFileSystem.java:149)at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:2596)at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:91)at org.apache.hadoop.fs.FileSystem$Cache.getInternal(FileSystem.java:2630)at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:2612)at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:370)at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:169)at com.newspace.HDFSDemo.init(HDFSDemo.java:33)at com.newspace.HDFSDemo.main(HDFSDemo.java:86)Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.fs.CanUnbufferat java.net.URLClassLoader$1.run(URLClassLoader.java:372)at java.net.URLClassLoader$1.run(URLClassLoader.java:361)at java.security.AccessController.doPrivileged(Native Method)at java.net.URLClassLoader.findClass(URLClassLoader.java:360)at java.lang.ClassLoader.loadClass(ClassLoader.java:424)at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)at java.lang.ClassLoader.loadClass(ClassLoader.java:357)... 21 more

该问题的出现是在本地访问服务器的时候，因为我本地的所有jar包都是自己从网上下载下来的，导致与公司服务器上的jar包不一致，然后出现了这样的错误
解决方案：
后来将本地的jar包全部干掉，然后从服务器上宕下所有需要的jar包，然后替换到本地，没有毛病了。