Question

我想将HDFS数据导出到mysql中。我做了一些我在下面给出的东西，我得到的可能是错误。

sqoop export --connect jdbc:mysql://vamshhi-Inspiron-N5010:3306/hadoop --username root --password root --table BankDetails --input-fields-terminated-by ','  --export-dir /user/vamshhi/BankOut001


Warning: /usr/lib/hcatalog does not exist! HCatalog jobs will fail.
Please set $HCAT_HOME to the root of your HCatalog installation.Warning: 
$HADOOP_HOME is deprecated.15/12/01 11:17:37 WARN tool.BaseSqoopTool: Setting 
your password on the command-line is insecure. Consider using -P instead.
15/12/01 11:17:37 INFO manager.MySQLManager: Preparing to use a MySQLstreaming resultset.
15/12/01 11:17:37 INFO tool.CodeGenTool: Beginning code generation
15/12/01 11:17:37 ERROR manager.SqlManager: Error executing statement: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1117)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:355)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2461)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2498)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2283)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:822)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:404)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:317)
    at java.sql.DriverManager.getConnection(DriverManager.java:571)
    at java.sql.DriverManager.getConnection(DriverManager.java:215)
    at org.apache.sqoop.manager.SqlManager.makeConnection(SqlManager.java:801)
    at org.apache.sqoop.manager.GenericJdbcManager.getConnection(GenericJdbcManager.java:52)
    at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:660)
    at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:683)
    at org.apache.sqoop.manager.SqlManager.getColumnTypesForRawQuery(SqlManager.java:240)
    at org.apache.sqoop.manager.SqlManager.getColumnTypes(SqlManager.java:223)
    at org.apache.sqoop.manager.ConnManager.getColumnTypes(ConnManager.java:347)
    at org.apache.sqoop.orm.ClassWriter.getColumnTypes(ClassWriter.java:1277)
    at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1089)
    at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:96)
    at org.apache.sqoop.tool.ExportTool.exportTable(ExportTool.java:64)
    at org.apache.sqoop.tool.ExportTool.run(ExportTool.java:100)
    at org.apache.sqoop.Sqoop.run(Sqoop.java:145)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
    at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:181)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:220)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:229)
    at org.apache.sqoop.Sqoop.main(Sqoop.java:238)
Caused by: java.net.ConnectException: Connection refused
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:579)
    at java.net.Socket.connect(Socket.java:528)
    at java.net.Socket.<init>(Socket.java:425)
    at java.net.Socket.<init>(Socket.java:241)
    at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:259)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:305)
    ... 32 more
15/12/01 11:17:37 ERROR tool.ExportTool: Encountered IOException running export job: java.io.IOException: No columns to generate for ClassWriter

我怎么能离开这里？我已经将mysql-connector导入到sqoop主文件夹中，直到我收到它。

Answer 1

jdbc:mysql://vamshhi-Inspiron-N5010:3306/hadoop

错误表示连接超时并且您正在使用上面的JDBC URL。

故障排除步骤：

检查连接ping vamshhi-Inspiron-N5010
检查数据库是否在指定端口上运行 telnet vamshhi-Inspiron-N5010 3306

如果第一个失败，那么您将无法连接到指定的主机如果第一个成功，第二个失败，那么mysql数据库没有运行。

您可以在我的YouTube playlist

中详细了解该主题

如何将HDFS数据导出到mysql？

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