问题描述：
在集群上运行jar架包，报错
java.lang.Exception: java.io.IOException: com.mysql.jdbc.Driver at org.apache.hadoop.mapred.LocalJobRunner$Job.runTasks(LocalJobRunner.java:492) at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:552) Caused by: java.io.IOException: com.mysql.jdbc.Driver at org.apache.hadoop.mapreduce.lib.db.DBOutputFormat.getRecordWriter(DBOutputFormat.java:197) at org.apache.hadoop.mapred.MapTask$NewDirectOutputCollector.(MapTask.java:659) at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:779) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:347) at org.apache.hadoop.mapred.LocalJobRunner$Job$MapTaskRunnable.run(LocalJobRunner.java:271) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)
原因分析： hadoop没有配置mysql连接jar包
解决方案：
将mysql-connector-java-5.1.27-bin.jar下载到{HADOOP_HOME}/share/hadoop/hdfs/lib下
注hadoop3版本与hadoop2版本目录有误差需要架包留言
