NoClassDefFoundError常見原因

常見原因

1. 沒有引入jar包；
2. jar包衝突；
3. pom中增加依賴後classpath沒有被更新；
4. maven依賴的scope設置不合理；

IDEA maven依賴scope爲provided報NoClassDefFoundError

現象

  eclipse中正常運行，IDEA中運行報錯：

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/hive/metastore/api/MetaException
	at java.lang.Class.getDeclaredMethods0(Native Method)
	at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
	at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
	at java.lang.Class.getMethod0(Class.java:3018)
	at java.lang.Class.getMethod(Class.java:1784)
	at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
	at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.hive.metastore.api.MetaException
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 7 more

maven依賴

<dependency>
      <groupId>org.apache.hive</groupId>
      <artifactId>hive-exec</artifactId>
      <version>1.2.1</version>
      <scope>provided</scope>
</dependency>

原因

  在IDEA中，maven配置provided，運行時依賴不起作用；

參考：

1. https://blog.csdn.net/u010936936/article/details/78499667