As underscore(_) is not allowed. It may be the problem if your other configuration are ok.

Your configuration file should be something like

<property>

<name>fs.default.name</name>

  <value>hdfs://masterServer:9000/</value>

</property>

http://stackoverflow.com/questions/27956973/java-io-ioexception-incomplete-hdfs-uri-no-host

所有文档在，

https://hadoop.apache.org/docs/r2.6.0/hadoop-project-dist/

下找。