storm-starter with intellij idea,maven project could not find class

问题:

I'm beginner of storm and intellij idea,when I import storm-starter(apache-storm-0.9.5.zip) to intellij idea(14 CE OS),everything is OK,but when I run the "ExclamationTopology" ,a problem appears as follow:

Exception in thread "main" java.lang.NoClassDefFoundError: backtype/storm/topology/IRichSpout 	at java.lang.Class.forName0(Native Method) 	at java.lang.Class.forName(Class.java:264) 	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:122) Caused by: java.lang.ClassNotFoundException: backtype.storm.topology.IRichSpout 	at java.net.URLClassLoader.findClass(URLClassLoader.java:381) 	at java.lang.ClassLoader.loadClass(ClassLoader.java:424) 	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) 	at java.lang.ClassLoader.loadClass(ClassLoader.java:357) 	... 3 more  Process finished with exit code 1

this interface is from storm-core,but this maven managed jar is in my library Why does this happened..?

回答1:

Strom already has required jar on the server side. So, if look into the pom.xml you find something similar to: https://github.com/apache/storm/blob/master/examples/storm-starter/pom.xml

<dependency>   <groupId>org.apache.storm</groupId>   <artifactId>storm-core</artifactId>   <version>${project.version}</version>   <!-- keep storm out of the jar-with-dependencies -->   <scope>provided</scope> </dependency> 

The provided scope is only available on the compilation and test classpath. Because of it your project compiles, but then fails in the runtime with exception : java.lang.NoClassDefFoundError.

Please, comment the scope line in your pom.xml and update maven dependencies to solve this problem. It should looks like:

<dependency>   <groupId>org.apache.storm</groupId>   <artifactId>storm-core</artifactId>   <version>${project.version}</version>   <!-- keep storm out of the jar-with-dependencies -->   <!-- <scope>provided</scope> --> </dependency> 

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