Question

我想使用hadoop map reduce从我的底层mysql数据库中读取数据，但即使将mysql jar文件添加到hadoop / lib文件夹后也会出现此异常。

Exception in thread "main" java.lang.RuntimeException: java.lang.RuntimeException: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
    at org.apache.hadoop.mapreduce.lib.db.DBInputFormat.setConf(DBInputFormat.java:169)
    at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:70)
    at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:130)
    at org.apache.hadoop.mapreduce.JobSubmitter.writeNewSplits(JobSubmitter.java:470)
    at org.apache.hadoop.mapreduce.JobSubmitter.writeSplits(JobSubmitter.java:490)
    at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:387)
    at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1218)
    at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1215)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1489)
    at org.apache.hadoop.mapreduce.Job.submit(Job.java:1215)
    at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1236)
    at DBCountPageView.run(DBCountPageView.java:227)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:84)
    at DBCountPageView.main(DBCountPageView.java:236)
    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:601)
    at org.apache.hadoop.util.RunJar.main(RunJar.java:212)
Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
    at org.apache.hadoop.mapreduce.lib.db.DBInputFormat.getConnection(DBInputFormat.java:195)
    at org.apache.hadoop.mapreduce.lib.db.DBInputFormat.setConf(DBInputFormat.java:163)
    ... 21 more
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:188)
    at org.apache.hadoop.mapreduce.lib.db.DBConfiguration.getConnection(DBConfiguration.java:148)
    at org.apache.hadoop.mapreduce.lib.db.DBInputFormat.getConnection(DBInputFormat.java:189)
    ... 22 more

Answer 1

您必须下载mysql-connector-java-version-bin.jar并将其添加到您的类路径中。有关详细信息，请参阅MySQL documentation。

java.lang.RuntimeException：java.lang.ClassNotFoundException：com.mysql.jdbc.Driver

1 个答案: