从hive将数据导出到mysql

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本文详细阐述了如何通过Hive将数据导出到MySQL，包括创建目标表、授权、解决NULL问题和使用特定参数进行数据导出的过程。通过实例演示，解决了Hive中遇到的权限和NULL值表示等问题，最终实现成功导出数据到MySQL。

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在上一篇文章《用sqoop进行mysql和hdfs系统间的数据互导》中，提到sqoop可以让RDBMS和HDFS之间互导数据，并且也支持从mysql中导入到HBase，但从HBase直接导入mysql则不是直接支持，而是间接支持。要么将HBase导出到HDFS平面文件，要么将其导出到Hive中，再导出到mysql。本篇讲从hive中导出到mysql。
从hive将数据导出到mysql

一、创建mysql表

mysql> create table award (rowkey varchar(255), productid int, matchid varchar(255), rank varchar(255), tourneyid varchar(255), userid bigint, gameid int, gold int, loginid varchar(255), nick varchar(255), plat varchar(255));
Query OK, 0 rows affected (0.01 sec)

二、尝试用hive作为外部数据库连接hbase，导入mysql

hive> CREATE EXTERNAL TABLE hive_award(key string, productid int,matchid string, rank string, tourneyid string, userid bigint,gameid int,gold int,loginid string,nick string,plat string) STORED BY 'org.apache.hadoop.hive.hbase.HBaseStorageHandler' WITH SERDEPROPERTIES ("hbase.columns.mapping" = ":key,info:MPID,info:MatchID,info:Rank,info:TourneyID,info:UserId,info:gameID,info:gold,info:loginId,info:nickName,info:platform") TBLPROPERTIES("hbase.table.name" = "award");

hive> desc hive_award;
key string from deserializer
productid int from deserializer
matchid string from deserializer
rank string from deserializer
tourneyid string from deserializer
userid bigint from deserializer
gameid int from deserializer
gold int from deserializer
loginid string from deserializer
nick string from deserializer
plat string from deserializer
[zhouhh@Hadoop46 ~]$ hadoop fs -ls /user/hive/warehouse/
Found 3 items
drwxr-xr-x - zhouhh supergroup 0 2012-07-16 14:08 /user/hive/warehouse/hive_award
drwxr-xr-x - zhouhh supergroup 0 2012-07-16 14:30 /user/hive/warehouse/nnnon
drwxr-xr-x - zhouhh supergroup 0 2012-07-16 13:53 /user/hive/warehouse/test222

[zhouhh@Hadoop46 ~]$ sqoop export --connect jdbc:mysql://Hadoop48/toplists -m 1 --table award --export-dir /user/hive/warehouse/hive_award --input-fields-terminated-by '\0001'
12/07/19 16:13:06 INFO manager.MySQLManager: Preparing to use a MySQL streaming resultset.

12/07/19 16:13:06 INFO tool.CodeGenTool: Beginning code generation
12/07/19 16:13:06 INFO manager.SqlManager: Executing SQL statement: SELECT t.* FROM `award` AS t LIMIT 1
12/07/19 16:13:06 INFO orm.CompilationManager: HADOOP_HOME is /home/zhouhh/hadoop-1.0.0/libexec/..
注: /tmp/sqoop-zhouhh/compile/4366149f0b6dd311c5b622594744fbb0/award.java使用或覆盖了已过时的 API。
注: 有关详细信息, 请使用 -Xlint:deprecation 重新编译。
12/07/19 16:13:08 INFO orm.CompilationManager: Writing jar file: /tmp/sqoop-zhouhh/compile/4366149f0b6dd311c5b622594744fbb0/award.jar
12/07/19 16:13:08 INFO mapreduce.ExportJobBase: Beginning export of award
12/07/19 16:13:09 WARN mapreduce.ExportJobBase: Input path hdfs://Hadoop46:9200/user/hive/warehouse/hive_award contains no files
12/07/19 16:13:11 INFO input.FileInputFormat: Total input paths to process : 0
12/07/19 16:13:11 INFO input.FileInputFormat: Total input paths to process : 0
12/07/19 16:13:13 INFO mapred.JobClient: Running job: job_201207191159_0059
12/07/19 16:13:14 INFO mapred.JobClient: map 0% reduce 0%
12/07/19 16:13:26 INFO mapred.JobClient: Job complete: job_201207191159_0059
12/07/19 16:13:26 INFO mapred.JobClient: Counters: 4
12/07/19 16:13:26 INFO mapred.JobClient: Job Counters
12/07/19 16:13:26 INFO mapred.JobClient: SLOTS_MILLIS_MAPS=7993
12/07/19 16:13:26 INFO mapred.JobClient: Total time spent by all reduces waiting after reserving slots (ms)=0
12/07/19 16:13:26 INFO mapred.JobClient: Total time spent by all maps waiting after reserving slots (ms)=0
12/07/19 16:13:26 INFO mapred.JobClient: SLOTS_MILLIS_REDUCES=0
12/07/19 16:13:26 INFO mapreduce.ExportJobBase: Transferred 0 bytes in 16.9678 seconds (0 bytes/sec)
12/07/19 16:13:26 INFO mapreduce.ExportJobBase: Exported 0 records.

 直接导外部表不成功，Input path hdfs://Hadoop46:9200/user/hive/warehouse/hive_award contains no files

三、hive中创建连结hbase的表，在hive中的插入会引起hbase的数据改变：

CREATE TABLE hive_award_data(key string,productid int,matchid string,rank string,
tourneyid string,userid bigint,gameid int,
gold int,loginid string,nick string,plat string)
STORED BY 'org.apache.hadoop.hive.hbase.HBaseStorageHandler' 
WITH SERDEPROPERTIES ("hbase.columns.mapping" = ":key,info:MPID,info:MatchID,info:Rank,info:TourneyID,info:UserId,info:gameID,info:gold,info:loginId,info:nickName,info:platform") TBLPROPERTIES("hbase.table.name" = "award_test");
hive> insert overwrite table hive_award_data select * from hive_award limit 2;
hbase(main):014:0> scan 'award_test'
ROW COLUMN+CELL
 2012-04-27 06:55:00:402713629 column=info:MPID, timestamp=1342754799918, value=5947
 2012-04-27 06:55:00:402713629 column=info:MatchID, timestamp=1342754799918, value=433203828
 2012-04-27 06:55:00:402713629 column=info:Rank, timestamp=1342754799918, value=2
 2012-04-27 06:55:00:402713629 column=info:TourneyID, timestamp=1342754799918, value=4027102
 2012-04-27 06:55:00:402713629 column=info:UserId, timestamp=1342754799918, value=402713629
 2012-04-27 06:55:00:402713629 column=info:gameID, timestamp=1342754799918, value=1001
 2012-04-27 06:55:00:402713629 column=info:loginId, timestamp=1342754799918, value=715878221
 2012-04-27 06:55:00:402713629 column=info:nickName, timestamp=1342754799918, value=xxx
 2012-04-27 06:55:00:402713629 column=info:platform, timestamp=1342754799918, value=ios
 2012-04-27 06:55:00:402713629 column=info:userid, timestamp=1342754445451, value=402713629
 2012-04-27 06:55:00:406788559 column=info:MPID, timestamp=1342754799918, value=778
 2012-04-27 06:55:00:406788559 column=info:MatchID, timestamp=1342754799918, value=433203930
 2012-04-27 06:55:00:406788559 column=info:Rank, timestamp=1342754799918, value=19
 2012-04-27 06:55:00:406788559 column=info:TourneyID, timestamp=1342754799918, value=4017780
 2012-04-27 06:55:00:406788559 column=info:UserId, timestamp=1342754799918, value=406788559
 2012-04-27 06:55:00:406788559 column=info:gameID, timestamp=1342754799918, value=1001
 2012-04-27 06:55:00:406788559 column=info:gold, timestamp=1342754799918, value=1
 2012-04-27 06:55:00:406788559 column=info:loginId, timestamp=1342754799918, value=13835155880
 2012-04-27 06:55:00:406788559 column=info:nickName, timestamp=1342754799918, value=xxx
 2012-04-27 06:55:00:406788559 column=info:platform, timestamp=1342754799918, value=android
2 row(s) in 0.0280 seconds
[zhouhh@Hadoop46 ~]$ sqoop export --connect jdbc:mysql://Hadoop48/toplists -m 1 --table award --export-dir /user/hive/warehouse/hive_award_data --input-fields-terminated-by '\0001'
12/07/20 11:32:01 WARN mapreduce.ExportJobBase: Input path hdfs://Hadoop46:9200/user/hive/warehouse/hive_award_data contains no files

创建连接HBase的表，还是不能导入。

四、创建Hive表，将HBase外部表的数据导入

hive> CREATE TABLE hive_myaward(key string,productid int,matchid string,rank string,tourneyid string,userid bigint,gameid int,gold int,loginid string,nick string,plat string);
hive> insert overwrite table hive_myaward select * from hive_award limit 2;

hive> select * from hive_myaward;
OK
2012-04-27 06:55:00:402713629 5947 433203828 2 4027102 402713629 1001 NULL 715878221 杀破天A ios
2012-04-27 06:55:00:406788559 778 433203930 19 4017780 406788559 1001 1 13835155880 亲牛牛旦旦 android
Time taken: 2.257 seconds
[zhouhh@Hadoop46 ~]$ sqoop export --connect jdbc:mysql://Hadoop48/toplists -m 1 --table award --export-dir /user/hive/warehouse/hive_myaward --input-fields-terminated-by '\0001'
java.io.IOException: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Access denied for user ''@'Hadoop48' to database 'toplists'

 权限问题，再授权一下 
 mysql> GRANT ALL PRIVILEGES ON *.* TO ''@'Hadoop48';
Query OK, 0 rows affected (0.03 sec)
mysql> GRANT ALL PRIVILEGES ON *.* TO ''@'localhost';
Query OK, 0 rows affected (0.00 sec)

五、解决Hive中遇到的空值NULL的问题：

[zhouhh@Hadoop46 ~]$ sqoop export --connect jdbc:mysql://Hadoop48/toplists -m 1 --table award --export-dir /user/hive/warehouse/hive_myaward --input-fields-terminated-by '\0001'
...
12/07/20 11:49:25 INFO mapred.JobClient: map 0% reduce 0%
12/07/20 11:49:37 INFO mapred.JobClient: Task Id : attempt_201207191159_0227_m_000000_0, Status : FAILED
java.lang.NumberFormatException: For input string: "\N"
 at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)

\N是什么东西呢？

[zhouhh@Hadoop46 ~]$ hadoop fs -cat /user/hive/warehouse/hive_myaward/000000_0 
2012-04-27 06:55:00:4027136295947433203828240271024027136291001\N715878221杀破天Aios
2012-04-27 06:55:00:4067885597784332039301940177804067885591001113835155880亲牛牛旦旦android

hive> select * from hive_myaward;
OK
2012-04-27 06:55:00:402713629 5947 433203828 2 4027102 402713629 1001 NULL 715878221 杀破天A ios
2012-04-27 06:55:00:406788559 778 433203930 19 4017780 406788559 1001 1 13835155880 亲牛牛旦旦 android
Time taken: 2.257 seconds

由于Hive的NULL用\N来表示，字段用\01来分割，换行用\n来换行，所以需增加相应的指示,注意转义字符\：

见：https://issues.cloudera.org/browse/SQOOP-188

[zhouhh@Hadoop46 ~]$ sqoop export --connect jdbc:mysql://Hadoop48/toplists -m 1 --table award --export-dir /user/hive/warehouse/hive_myaward/000000_0 --input-null-string "\\\\N" --input-null-non-string "\\\\N" --input-fields-terminated-by "\\01" --input-lines-terminated-by "\\n"

12/07/20 12:53:56 INFO manager.MySQLManager: Preparing to use a MySQL streaming resultset.
12/07/20 12:53:56 INFO tool.CodeGenTool: Beginning code generation
12/07/20 12:53:56 INFO manager.SqlManager: Executing SQL statement: SELECT t.* FROM `award` AS t LIMIT 1
12/07/20 12:53:56 INFO orm.CompilationManager: HADOOP_HOME is /home/zhouhh/hadoop-1.0.0/libexec/..
注: /tmp/sqoop-zhouhh/compile/4427d3db678bb145c995073e0924dc0b/award.java使用或覆盖了已过时的 API。
注: 有关详细信息, 请使用 -Xlint:deprecation 重新编译。
12/07/20 12:53:57 ERROR orm.CompilationManager: Could not rename /tmp/sqoop-zhouhh/compile/4427d3db678bb145c995073e0924dc0b/award.java to /home/zhouhh/./award.java
12/07/20 12:53:57 INFO orm.CompilationManager: Writing jar file: /tmp/sqoop-zhouhh/compile/4427d3db678bb145c995073e0924dc0b/award.jar
12/07/20 12:53:57 INFO mapreduce.ExportJobBase: Beginning export of award
12/07/20 12:53:58 INFO input.FileInputFormat: Total input paths to process : 1
12/07/20 12:53:58 INFO input.FileInputFormat: Total input paths to process : 1
12/07/20 12:53:58 INFO mapred.JobClient: Running job: job_201207191159_0232
12/07/20 12:53:59 INFO mapred.JobClient: map 0% reduce 0%
12/07/20 12:54:12 INFO mapred.JobClient: map 100% reduce 0%
12/07/20 12:54:17 INFO mapred.JobClient: Job complete: job_201207191159_0232
12/07/20 12:54:17 INFO mapred.JobClient: Counters: 18
12/07/20 12:54:17 INFO mapred.JobClient: Job Counters
12/07/20 12:54:17 INFO mapred.JobClient: SLOTS_MILLIS_MAPS=12114
12/07/20 12:54:17 INFO mapred.JobClient: Total time spent by all reduces waiting after reserving slots (ms)=0
12/07/20 12:54:17 INFO mapred.JobClient: Total time spent by all maps waiting after reserving slots (ms)=0
12/07/20 12:54:17 INFO mapred.JobClient: Rack-local map tasks=1
12/07/20 12:54:17 INFO mapred.JobClient: Launched map tasks=1
12/07/20 12:54:17 INFO mapred.JobClient: SLOTS_MILLIS_REDUCES=0
12/07/20 12:54:17 INFO mapred.JobClient: File Output Format Counters
12/07/20 12:54:17 INFO mapred.JobClient: Bytes Written=0
12/07/20 12:54:17 INFO mapred.JobClient: FileSystemCounters
12/07/20 12:54:17 INFO mapred.JobClient: HDFS_BYTES_READ=335
12/07/20 12:54:17 INFO mapred.JobClient: FILE_BYTES_WRITTEN=30172
12/07/20 12:54:17 INFO mapred.JobClient: File Input Format Counters
12/07/20 12:54:17 INFO mapred.JobClient: Bytes Read=0
12/07/20 12:54:17 INFO mapred.JobClient: Map-Reduce Framework
12/07/20 12:54:17 INFO mapred.JobClient: Map input records=2
12/07/20 12:54:17 INFO mapred.JobClient: Physical memory (bytes) snapshot=78696448
12/07/20 12:54:17 INFO mapred.JobClient: Spilled Records=0
12/07/20 12:54:17 INFO mapred.JobClient: CPU time spent (ms)=390
12/07/20 12:54:17 INFO mapred.JobClient: Total committed heap usage (bytes)=56623104
12/07/20 12:54:17 INFO mapred.JobClient: Virtual memory (bytes) snapshot=891781120
12/07/20 12:54:17 INFO mapred.JobClient: Map output records=2
12/07/20 12:54:17 INFO mapred.JobClient: SPLIT_RAW_BYTES=123
12/07/20 12:54:17 INFO mapreduce.ExportJobBase: Transferred 335 bytes in 19.6631 seconds (17.037 bytes/sec)
12/07/20 12:54:17 INFO mapreduce.ExportJobBase: Exported 2 records.

 导出到mysql成功 
 mysql> use toplists;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from award;
+-------------------------------+-----------+-----------+------+-----------+-----------+--------+------+-------------+-------+---------+
| rowkey | productid | matchid | rank | tourneyid | userid | gameid | gold | loginid | nick | plat |
+-------------------------------+-----------+-----------+------+-----------+-----------+--------+------+-------------+-------+---------+
| 2012-04-27 06:55:00:402713629 | 5947 | 433203828 | 2 | 4027102 | 402713629 | 1001 | NULL | 715878221 | ???A | ios |
| 2012-04-27 06:55:00:406788559 | 778 | 433203930 | 19 | 4017780 | 406788559 | 1001 | 1 | 13835155880 | ????? | android |
+-------------------------------+-----------+-----------+------+-----------+-----------+--------+------+-------------+-------+---------+
2 rows in set (0.00 sec)