使用命令进行mysql数据库连接时出现错误。
错误信息
2022-02-12 00:33:08,978 INFO manager.MySQLManager: Preparing to use a MySQL streaming resultset.
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/lang/StringUtils
at org.apache.sqoop.manager.MySQLManager.initOptionDefaults(MySQLManager.java:73)
at org.apache.sqoop.manager.SqlManager.<init>(SqlManager.java:89)
at com.cloudera.sqoop.manager.SqlManager.<init>(SqlManager.java:33)
at org.apache.sqoop.manager.GenericJdbcManager.<init>(GenericJdbcManager.java:51)
at com.cloudera.sqoop.manager.GenericJdbcManager.<init>(GenericJdbcManager.java:30)
at org.apache.sqoop.manager.CatalogQueryManager.<init>(CatalogQueryManager.java:46)
at com.cloudera.sqoop.manager.CatalogQueryManager.<init>(CatalogQueryManager.java:31)
at org.apache.sqoop.manager.InformationSchemaManager.<init>(InformationSchemaManager.java:38)
at com.cloudera.sqoop.manager.InformationSchemaManager.<init>(InformationSchemaManager.java:31)
at org.apache.sqoop.manager.MySQLManager.<init>(MySQLManager.java:65)
at org.apache.sqoop.manager.DefaultManagerFactory.accept(DefaultManagerFactory.java:67)
at org.apache.sqoop.ConnFactory.getManager(ConnFactory.java:184)
at org.apache.sqoop.tool.BaseSqoopTool.init(BaseSqoopTool.java:272)
at org.apache.sqoop.tool.ListTablesTool.run(ListTablesTool.java:44)
at org.apache.sqoop.Sqoop.run(Sqoop.java:147)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:183)
at org.apache.sqoop.Sqoop.runTool(Sqoop.java:234)
at org.apache.sqoop.Sqoop.runTool(Sqoop.java:243)
at org.apache.sqoop.Sqoop.main(Sqoop.java:252)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.lang.StringUtils
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 20 more问题原因
原因在异常中已经很明显了：没有找到类 org.apache.commons.lang.StringUtils 也就是说Sqoop中没有这个类或者包含这个类的jar包。但是我查看lib目录下的jar包，是包含commons-lang3的。上网查到因为Sqoop版本大部分是支持2 的。
解决办法
将Sqoop下的commons-lang3替换成commons-lang-2.6.jar。
1.下载commons-lang-2.6.jar，下载地址https://mvnrepository.com/
2.将commons-lang-2.6.jar 上传到sqoop安装目录的lib目录下，同时删除原来的jar。
测试
sqoop list-databases \
--connect jdbc:mysql://master:3306/ \
--username root \
--password root结果如下：
