Hi Shixiong, would you mind describing your use case a bit more? Based on the description it seems that you're re-packaging Sqoop with your own code and mysql JDBC driver together.
Jarcec On Fri, Apr 19, 2013 at 04:48:08PM +0800, Shixiong Zhu wrote: > Hi, > > For option 1: I can not add jars in our cluster as no permission. And we > also want to keep our cluster clean and stable. > > For option 2: It does not work as the jars from "-libjar" are not loaded > in the client process. > > However, an optional solution is adding my jar to HADOOP_CLASSPATH. > > But here I want to know is why does DBConfiguration not use > "conf.getClassByName" to load the jdbc driver? > > 2013/4/19 vasanth kumar <[email protected]> > > > Hi, > > > > No need to pack mysql packages into your jar. > > Option 1: Copy mysql jdbc jar into $HADOOP_HOME/lib. Restart hadoop > > daemons. > > > > Option 2: while executing try : *$hadoop jar your.jar a.b.c.Main -libjar > > /path/mysql.jar* > > > > > > On Fri, Apr 19, 2013 at 12:32 PM, Shixiong Zhu <[email protected]> wrote: > > > >> Hi, > >> > >> I encountered a ClassNotFoundException when I used DBInputFormat. I > >> packaged my codes with mysql-connector-java-5.1.24.jar to abc.jar. Then I > >> run the following command to run: > >> > >> hadoop jar abc.jar a.b.c.Main > >> > >> But it is crashed by the following exception: > >> > >> Notes: java.lang.RuntimeException: java.lang.RuntimeException: > >> java.lang.ClassNotFoundException: com.mysql.jdbc.Driver > >> at > >> org.apache.hadoop.mapreduce.lib.db.DBInputFormat.setConf(DBInputFormat.java:158) > >> at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:70) > >> at > >> org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:130) > >> at org.apache.hadoop.mapred.JobClient.writeNewSplits(JobClient.java:959) > >> at org.apache.hadoop.mapred.JobClient.writeSplits(JobClient.java:979) > >> at org.apache.hadoop.mapred.JobClient.access$500(JobClient.java:170) > >> at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:891) > >> at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:844) > >> at java.security.AccessController.doPrivileged(Native Method) > >> at javax.security.auth.Subject.doAs(Subject.java:416) > >> at > >> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1232) > >> at > >> org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:844) > >> at org.apache.hadoop.mapreduce.Job.submit(Job.java:481) > >> at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:511) > >> ... > >> at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70) > >> at > >> com.microstrategy.etl.alert.feedback.FeedbackDumpTask.main(FeedbackDumpTask.java:17) > >> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > >> at > >> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) > >> at > >> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) > >> at java.lang.reflect.Method.invoke(Method.java:616) > >> at org.apache.hadoop.util.RunJar.main(RunJar.java:208) > >> Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException: > >> com.mysql.jdbc.Driver > >> at > >> org.apache.hadoop.mapreduce.lib.db.DBInputFormat.getConnection(DBInputFormat.java:184) > >> at > >> org.apache.hadoop.mapreduce.lib.db.DBInputFormat.setConf(DBInputFormat.java:152) > >> ... 25 more > >> Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver > >> at java.net.URLClassLoader$1.run(URLClassLoader.java:217) > >> at java.security.AccessController.doPrivileged(Native Method) > >> at java.net.URLClassLoader.findClass(URLClassLoader.java:205) > >> at java.lang.ClassLoader.loadClass(ClassLoader.java:321) > >> at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294) > >> at java.lang.ClassLoader.loadClass(ClassLoader.java:266) > >> at java.lang.Class.forName0(Native Method) > >> at java.lang.Class.forName(Class.java:186) > >> at > >> org.apache.hadoop.mapreduce.lib.db.DBConfiguration.getConnection(DBConfiguration.java:143) > >> at > >> org.apache.hadoop.mapreduce.lib.db.DBInputFormat.getConnection(DBInputFormat.java:178) > >> ... 26 more > >> > >> I read the DBConfiguration.java file, and found it uses "Class.forName" > >> to load "com.mysql.jdbc.Driver": > >> > >> /** Returns a connection object to the DB. > >> * @throws ClassNotFoundException > >> * @throws SQLException */ > >> public Connection getConnection() > >> throws ClassNotFoundException, SQLException { > >> Connection connection; > >> > >> Class.forName(conf.get(DBConfiguration.DRIVER_CLASS_PROPERTY)); > >> > >> I think that's why my application crashed. The classloader of > >> DBConfiguration is sun.misc.Launcher$AppClassLoader, but > >> "com.mysql.jdbc.Driver" exists in the URLClassLoader created by > >> org.apache.hadoop.util.RunJar. > >> So "Class.forName" invoked by DBConfiguration can not find > >> "com.mysql.jdbc.Driver" in the sun.misc.Launcher$AppClassLoader. > >> > >> Why does DBConfiguration not use "conf.getClassByName" to load the jdbc > >> driver? If DBConfiguration use the following code, it can work in such > >> situation. > >> > >> conf.getClassByName(conf.get(DBConfiguration.DRIVER_CLASS_PROPERTY)); > >> > >> Is there any similar issue? Sorry that I can not find any JIRA about this > >> problem. > >> > >> -- > >> Thanks, > >> Shixiong Zhu > >> > > > > > > > > -- > > Regards > > Vasanth kumar RJ > >
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