导致No columns to generate for Cla

用Hadoop全家桶中的sqoop的job去导数据时遇到了些问题，现在记载下来。

2953 [main] INFO  org.apache.sqoop.tool.CodeGenTool  - Beginning code generation
3034 [main] ERROR org.apache.sqoop.manager.SqlManager  - Error executing statement: java.sql.SQLException: Access denied for user 'user'@'172.16.ip.ip' (using password: NO)
java.sql.SQLException: Access denied for user 'user'@'172.16.ip.ip' (using password: NO)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1094)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4208)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4140)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:925)
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1747)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1287)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2494)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2527)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2309)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:419)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at org.apache.sqoop.manager.SqlManager.makeConnection(SqlManager.java:904)
    at org.apache.sqoop.manager.GenericJdbcManager.getConnection(GenericJdbcManager.java:52)
    at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:763)
    at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:786)
    at org.apache.sqoop.manager.SqlManager.getColumnInfoForRawQuery(SqlManager.java:289)
    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:328)
    at org.apache.sqoop.orm.ClassWriter.getColumnTypes(ClassWriter.java:1853)
    at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1653)
    at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:107)
    at org.apache.sqoop.tool.ImportTool.importTable(ImportTool.java:488)
    at org.apache.sqoop.tool.ImportTool.run(ImportTool.java:615)
    at org.apache.sqoop.tool.JobTool.execJob(JobTool.java:243)
    at org.apache.sqoop.tool.JobTool.run(JobTool.java:298)
    at org.apache.sqoop.Sqoop.run(Sqoop.java:147)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
    at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:183)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:225)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:234)
    at org.apache.sqoop.Sqoop.main(Sqoop.java:243)
    at org.apache.oozie.action.hadoop.SqoopMain.runSqoopJob(SqoopMain.java:197)
    at org.apache.oozie.action.hadoop.SqoopMain.run(SqoopMain.java:179)
    at org.apache.oozie.action.hadoop.LauncherMain.run(LauncherMain.java:58)
    at org.apache.oozie.action.hadoop.SqoopMain.main(SqoopMain.java:48)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.oozie.action.hadoop.LauncherMapper.map(LauncherMapper.java:240)
    at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:54)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:453)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
    at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:170)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1869)
    at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:164)
3034 [main] ERROR org.apache.sqoop.manager.SqlManager  - Error executing statement: java.sql.SQLException: Access denied for user 'user'@'172.16.ip.ip' (using password: NO)
java.sql.SQLException: Access denied for user 'user'@'172.16.ip.ip' (using password: NO)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1094)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4208)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4140)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:925)
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1747)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1287)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2494)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2527)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2309)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:419)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at org.apache.sqoop.manager.SqlManager.makeConnection(SqlManager.java:904)
    at org.apache.sqoop.manager.GenericJdbcManager.getConnection(GenericJdbcManager.java:52)
    at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:763)
    at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:786)
    at org.apache.sqoop.manager.SqlManager.getColumnInfoForRawQuery(SqlManager.java:289)
    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:328)
    at org.apache.sqoop.orm.ClassWriter.getColumnTypes(ClassWriter.java:1853)
    at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1653)
    at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:107)
    at org.apache.sqoop.tool.ImportTool.importTable(ImportTool.java:488)
    at org.apache.sqoop.tool.ImportTool.run(ImportTool.java:615)
    at org.apache.sqoop.tool.JobTool.execJob(JobTool.java:243)
    at org.apache.sqoop.tool.JobTool.run(JobTool.java:298)
    at org.apache.sqoop.Sqoop.run(Sqoop.java:147)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
    at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:183)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:225)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:234)
    at org.apache.sqoop.Sqoop.main(Sqoop.java:243)
    at org.apache.oozie.action.hadoop.SqoopMain.runSqoopJob(SqoopMain.java:197)
    at org.apache.oozie.action.hadoop.SqoopMain.run(SqoopMain.java:179)
    at org.apache.oozie.action.hadoop.LauncherMain.run(LauncherMain.java:58)
    at org.apache.oozie.action.hadoop.SqoopMain.main(SqoopMain.java:48)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.oozie.action.hadoop.LauncherMapper.map(LauncherMapper.java:240)
    at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:54)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:453)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
    at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:170)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1869)
    at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:164)
3037 [main] ERROR org.apache.sqoop.tool.ImportTool  - Encountered IOException running import job: java.io.IOException: No columns to generate for ClassWriter
    at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1659)
    at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:107)
    at org.apache.sqoop.tool.ImportTool.importTable(ImportTool.java:488)
    at org.apache.sqoop.tool.ImportTool.run(ImportTool.java:615)
    at org.apache.sqoop.tool.JobTool.execJob(JobTool.java:243)
    at org.apache.sqoop.tool.JobTool.run(JobTool.java:298)
    at org.apache.sqoop.Sqoop.run(Sqoop.java:147)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
    at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:183)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:225)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:234)
    at org.apache.sqoop.Sqoop.main(Sqoop.java:243)
    at org.apache.oozie.action.hadoop.SqoopMain.runSqoopJob(SqoopMain.java:197)
    at org.apache.oozie.action.hadoop.SqoopMain.run(SqoopMain.java:179)
    at org.apache.oozie.action.hadoop.LauncherMain.run(LauncherMain.java:58)
    at org.apache.oozie.action.hadoop.SqoopMain.main(SqoopMain.java:48)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.oozie.action.hadoop.LauncherMapper.map(LauncherMapper.java:240)
    at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:54)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:453)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
    at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:170)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1869)
    at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:164)

3037 [main] ERROR org.apache.sqoop.tool.ImportTool  - Encountered IOException running import job: java.io.IOException: No columns to generate for ClassWriter
    at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1659)
    at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:107)
    at org.apache.sqoop.tool.ImportTool.importTable(ImportTool.java:488)
    at org.apache.sqoop.tool.ImportTool.run(ImportTool.java:615)
    at org.apache.sqoop.tool.JobTool.execJob(JobTool.java:243)
    at org.apache.sqoop.tool.JobTool.run(JobTool.java:298)
    at org.apache.sqoop.Sqoop.run(Sqoop.java:147)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
    at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:183)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:225)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:234)
    at org.apache.sqoop.Sqoop.main(Sqoop.java:243)
    at org.apache.oozie.action.hadoop.SqoopMain.runSqoopJob(SqoopMain.java:197)
    at org.apache.oozie.action.hadoop.SqoopMain.run(SqoopMain.java:179)
    at org.apache.oozie.action.hadoop.LauncherMain.run(LauncherMain.java:58)
    at org.apache.oozie.action.hadoop.SqoopMain.main(SqoopMain.java:48)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.oozie.action.hadoop.LauncherMapper.map(LauncherMapper.java:240)
    at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:54)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:453)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
    at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:170)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1869)
    at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:164)


<<< Invocation of Sqoop command completed <<<

报如上错误，网上查询说‘No columns to generate for ClassWriter’这种错误都是由于mysql驱动mysql-connector-java.jar的旧版本bug导致的。其实仔细看下“using password: NO”这句报错，明显是没有配置密码导致的。
参考(官方文档)[http://sqoop.apache.org/docs/1.4.6/SqoopUserGuide.html#_syntax_6]，这里注意有个单独的“--”，这后面还配置了用户名和密码。

$ sqoop job --exec myjob -- --username someuser -P
Enter password:
...

如果不想以交互式写入密码，也可以写在语句里：

$ sqoop job --exec myjob -- --username someuser --password xxxx