hadoop运行jar包报错

执行命令：[root@hadoop102 mapreduce]# hadoop jar mapreduce2_maven.jar Filter

错误信息：
Exception in thread "main" java.lang.ClassNotFoundException: Filter
    at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.apache.hadoop.util.RunJar.run(RunJar.java:311)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:232)
解决方法：将 hadoop jar mapreduce2_maven.jar Filter改为hadoop jar mapreduce2_maven.jar exper.Filter

错误原因：类路径问题