ERROR tool.ExportTool: Error during export: because
Export job failed!
at org.apache.sqoop.mapreduce.ExportJobBase.runExport(ExportJobBase.java:439)
at org.apache.sqoop.manager.SqlManager.exportTable(SqlManager.java:931)
at org.apache.sqoop.tool.ExportTool.exportTable(ExportTool.java:80)
at org.apache.sqoop.tool.ExportTool.run(ExportTool.java:99)
at org.apache.sqoop.Sqoop.run(Sqoop.java:147)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
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)
Warning: /usr/lib/sqoop/../accumulo does not exist! Accumulo imports will fail.
sqoop import export其实也是mapreduce ，然后问题出现在map阶段执行完，export 到mysql中
大概原因是：hive表结构和mysql表结构不一致，主要表现在
字段数量，字段类型，非空约束等比如说hive表结构中有null，而mysql却有非空约束，显然会错，
还有sqoop导出到mysql需要指定export -dir 为hdfs上的路径，确定hdfs路径是否有问题，hdfs路径下是否有多个文件，
如果sqoop被azkaban执行的话，还需要在sqoop任务中添加jdk路径，jdk路径是否正确
export JAVA_HOME=/usr/local/jdk1.8
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$JAVA_HOME/bin:$PATH