我想要做的: 該程序旨在從SQL Server 2008加載區域銷售數據,並在MapReduce上運行簡單的統計計算以獲得每個區域的總銷售額。我得到的錯誤說程序找不到sqljdbc4.jar文件,但是,該文件確實已經複製到代碼中指定的位置。在Hadoop中訪問SQL Server
所以喜歡代碼:
//fileName: MRExp.java public class MRExp { public static void main(String[] args) throws IOException { JobConf conf = new JobConf(MRExp.class); DistributedCache.addFileToClassPath(new Path("/userX/sqljdbc4.jar"), conf); conf.setMapperClass(MRMapper.class); conf.setReducerClass(MRReducer.class); conf.setMapOutputKeyClass(Text.class); conf.setMapOutputValueClass(LongWritable.class); conf.setOutputKeyClass(LongWritable.class); conf.setOutputValueClass(Text.class); conf.setInputFormat(DBInputFormat.class); FileOutputFormat.setOutputPath(conf, new Path(args[0])); DBConfiguration .configureDB( conf, "com.microsoft.sqlserver.jdbc.SQLServerDriver", "jdbc:sqlserver://MyDbServerAddr:1433;databaseName=ThisDb;integratedSecurity=true;", "db_userName", "db_Pws"); DBInputFormat .setInput(conf, InfoUnit.class, "SELECT R_NAME,L_ORDERKEY from dbo.United10MB ;"/* inputQuery */ , "SELECT COUNT(L_ORDERKEY) from dbo.United10MB"/* inputCountQuery */); try { JobClient.runJob(conf); } catch (Exception e) { e.printStackTrace(); } } }
//其次MRMapper和MRReducer和資訊室的定義。 InfoUnit實現了Writable,DBWritable。
文件位置:
[根@測試MRExp]#PWD
/根/ MRExp
[根@測試MRExp]#LS
類的hadoop-0.20.2-core.jar添加MRExp。的java sqljdbc4.jar然後,編譯MRExp.java:
[根@測試MRExp]#javac的-classpath的hadoop-0.20.2-core.jar添加-d類/ MRExp.java
[root @ test MRExp]#jar -cvf MRExp.jar -C classes /。
也複製到sqljdbc4.jar HDFS:
[[email protected] MRExp]# hadoop dfs -copyFromLocal sqljdbc4.jar /userX
所以我們得到:
[[email protected] MRExp]# ls
classes hadoop-0.20.2-core.jar MRExp.jar MRExp.java sqljdbc4.jar
以上後,火MAPR過程:
[root @ test MRExp]#hadoop jar MRExp.jar mrexp.MRExp/userX/output
但程序上寫着:
17:02:50 WARN mapreduce.JobSubmitter: Use GenericOptionsParser for parsing the arguments. Applications should implement Tool for the same.
12/10/28 17:02:50 INFO mapreduce.JobSubmitter: Cleaning up the staging area /tmp/hadoop-yarn/staging/root/.staging/job_1350984913454_0009
java.lang.RuntimeException: java.lang.RuntimeException: java.lang.ClassNotFoundException: com.microsoft.sqlserver.jdbc.SQLServerDriver
at org.apache.hadoop.mapreduce.lib.db.DBInputFormat.setConf(DBInputFormat.java:165)
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.JobConf.getInputFormat(JobConf.java:607)
at org.apache.hadoop.mapreduce.JobSubmitter.writeOldSplits(JobSubmitter.java:476)
at org.apache.hadoop.mapreduce.JobSubmitter.writeSplits(JobSubmitter.java:468)
at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:359)
at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1226)
at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1223)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1232)
at org.apache.hadoop.mapreduce.Job.submit(Job.java:1223)
at org.apache.hadoop.mapred.JobClient$1.run(JobClient.java:609)
at org.apache.hadoop.mapred.JobClient$1.run(JobClient.java:604)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1232)
at org.apache.hadoop.mapred.JobClient.submitJob(JobClient.java:604)
at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:880)
at mrexp.MRExp.main(MRExp.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.RunJar.main(RunJar.java:208)
Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException: com.microsoft.sqlserver.jdbc.SQLServerDriver
at org.apache.hadoop.mapreduce.lib.db.DBInputFormat.getConnection(DBInputFormat.java:191)
at org.apache.hadoop.mapreduce.lib.db.DBInputFormat.setConf(DBInputFormat.java:159)
... 25 more
Caused by: java.lang.ClassNotFoundException: com.microsoft.sqlserver.jdbc.SQLServerDriver
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at org.apache.hadoop.mapreduce.lib.db.DBConfiguration.getConnection(DBConfiguration.java:148)
at org.apache.hadoop.mapreduce.lib.db.DBInputFormat.getConnection(DBInputFormat.java:185)
... 26 more