异常 Failed to start agent because dependencies were not found in
classpath. Error follows. java.lang.NoClassDefFoundError
org/apache/hadoop/io/SequenceFile$CompressionType问题原因：缺少依赖包，这个依赖包是以下jar文件：
${HADOOP_HOME}share/hadoop/common/hadoop-common-2.7.2.jar
解决方法：找到这个jar文件，copy到flume安装目录下的lib目录下就ok了。
