ERROR manager.SqlManager: Error executing statement: java.sql.SQLException: Access denied for user '

在使用Sqoop将数据从Hive导入MySQL过程中，出现一下错误

Warning: /usr/local/sqoop/../hcatalog does not exist! HCatalog jobs will fail.
Please set $HCAT_HOME to the root of your HCatalog installation.
Warning: /usr/local/sqoop/../accumulo does not exist! Accumulo imports will fail.
Please set $ACCUMULO_HOME to the root of your Accumulo installation.
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/usr/local/hadoop/share/hadoop/common/lib/slf4j-log4j12-1.7.25.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/usr/local/hbase/lib/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
18/04/08 17:13:53 INFO sqoop.Sqoop: Running Sqoop version: 1.4.6
18/04/08 17:13:53 WARN tool.BaseSqoopTool: Setting your password on the command-line is insecure. Consider using -P instead.
18/04/08 17:13:53 INFO manager.MySQLManager: Preparing to use a MySQL streaming resultset.
18/04/08 17:13:53 INFO tool.CodeGenTool: Beginning code generation
Sun Apr 08 17:13:54 CST 2018 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
18/04/08 17:13:54 ERROR manager.SqlManager: Error executing statement: java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3970)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3906)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:873)
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1710)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1226)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2253)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2284)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2083)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:806)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    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:425)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:410)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:328)
    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:885)
    at org.apache.sqoop.manager.GenericJdbcManager.getConnection(GenericJdbcManager.java:52)
    at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:744)
    at org.apache.sqoop.manager.SqlManager.execute(SqlManager.java:767)
    at org.apache.sqoop.manager.SqlManager.getColumnInfoForRawQuery(SqlManager.java:270)
    at org.apache.sqoop.manager.SqlManager.getColumnTypesForRawQuery(SqlManager.java:241)
    at org.apache.sqoop.manager.SqlManager.getColumnTypes(SqlManager.java:227)
    at org.apache.sqoop.manager.ConnManager.getColumnTypes(ConnManager.java:295)
    at org.apache.sqoop.orm.ClassWriter.getColumnTypes(ClassWriter.java:1833)
    at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1645)
    at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:107)
    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:143)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
    at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:179)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:218)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:227)
    at org.apache.sqoop.Sqoop.main(Sqoop.java:236)
18/04/08 17:13:54 ERROR tool.ExportTool: Encountered IOException running export job: java.io.IOException: No columns to generate for ClassWriter

在反复查阅网上上资料后，发现是自己的操作权限不够。

bin/sqoop export --connect jdbc:mysql://localhost:3306/dbtaobao --username root --password root --table user_log --export-dir '/user/hive/warehouse/dbtaobao.db/inner_user_log' --fields-terminated-by ',';

字段解释：

./bin/sqoop export ##表示数据从 hive 复制到 mysql 中
–connect jdbc:mysql://localhost:3306/dbtaobao
–username root #mysql登陆用户名
–password root #登录密码
–table user_log #mysql 中的表，即将被导入的表名称
–export-dir ‘/user/hive/warehouse/dbtaobao.db/user_log ‘ #hive 中被导出的文件
–fields-terminated-by ‘,’ #Hive 中被导出的文件字段的分隔符

在执行这条命令时，我用的是root用户，但是我的jdbc:mysql://localhost:3306是localhost，因此需要修改localhost的权限，

用命令service mysql start确保mysql已经启动，

进入操作界面 mysql -u root -p,按提示输入的mysql密码，

hadoop@xxx-Inspiron-5555:/usr/local/sqoop$ mysql -u root -p
Enter password:

然后执行下面命令修改远程登录权限

mysql> grant all privileges on *.* to root@localhost identified by 'root';
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.04 sec)