用sqoop导入数据到hdfs时出现了错误，
代码如下：
bin/sqoop import
--connect jdbc:mysql://slave2:3306/company
--username root
--password 123456
--table staff
--target-dir /user/company
--delete-target-dir
--num-mappers 1
--fields-terminated-by "\t"
错误如下：
ERROR manager.SqlManager: Error reading from database: java.sql.SQLException: Streaming result set com.mysql.jdbc.RowDataDynamic@50eac852 is still active. No statements may be issued when any streaming result sets are open and in use on a given connection. Ensure that you have called .close() on any active streaming result sets before attempting more queries.
java.sql.SQLException: Streaming result set com.mysql.jdbc.RowDataDynamic@50eac852 is still active. No statements may be issued when any streaming result sets are open and in use on a given connection. Ensure that you have called .close() on any active streaming result sets before attempting more queries.
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:931)
at com.mysql.jdbc.MysqlIO.checkForOutstandingStreamingData(MysqlIO.java:2518)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1748)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1961)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2537)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2466)
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1383)
at com.mysql.jdbc.ConnectionImpl.getMaxBytesPerChar(ConnectionImpl.java:2939)
at com.mysql.jdbc.Field.getMaxBytesPerCharacter(Field.java:576)
at com.mysql.jdbc.ResultSetMetaData.getPrecision(ResultSetMetaData.java:440)
at org.apache.sqoop.manager.SqlManager.getColumnInfoForRawQuery(SqlManager.java:305)
at org.apache.sqoop.manager.SqlManager.getColumnTypesForRawQuery(SqlManager.java:260)
at org.apache.sqoop.manager.SqlManager.getColumnTypes(SqlManager.java:246)
at org.apache.sqoop.manager.ConnManager.getColumnTypes(ConnManager.java:327)
at org.apache.sqoop.orm.ClassWriter.getColumnTypes(ClassWriter.java:1872)
at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1671)
at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:106)
at org.apache.sqoop.tool.ImportTool.importTable(ImportTool.java:501)
at org.apache.sqoop.tool.ImportTool.run(ImportTool.java:628)
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)
19/03/04 02:52:22 ERROR tool.ImportTool: Import failed: java.io.IOException: No columns to generate for ClassWriter
at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1677)
at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:106)
at org.apache.sqoop.tool.ImportTool.importTable(ImportTool.java:501)
at org.apache.sqoop.tool.ImportTool.run(ImportTool.java:628)
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)
这个错误是较老的mysql-connect-java.jar的bug导致，把安装目录下lib目录里的mysql驱动包包换成mysql-connector-java-5.1.32-bin.jar就可以了。