Sqoop基本语法简介

约定不等于承诺〃 2022-05-21 09:28 146阅读 0赞

**简介：**  
本篇文章主要介绍sqoop的基本语法及简单使用方法。

##### 1.查看命令帮助 #####

[hadoop@hadoop000 ~]$ sqoop help
    usage: sqoop COMMAND [ARGS]
    
    Available commands:
      codegen            Generate code to interact with database records
      create-hive-table Import a table definition into Hive eval Evaluate a SQL statement and display the results export Export an HDFS directory to a database table help List available commands import Import a table from a database to HDFS import-all-tables Import tables from a database to HDFS import-mainframe Import datasets from a mainframe server to HDFS job Work with saved jobs list-databases List available databases on a server list-tables List available tables in a database merge Merge results of incremental imports metastore Run a standalone Sqoop metastore version Display version information See 'sqoop help COMMAND' for information on a specific command. # 这里提示我们使用sqoop help command（要查询的命令）进行该命令的详细查询

##### 2.list-databases #####

# 查看list-databases命令帮助
    [hadoop@hadoop000 ~]$ sqoop help list-databases
    usage: sqoop list-databases [GENERIC-ARGS] [TOOL-ARGS]
    
    Common arguments:
       --connect <jdbc-uri> Specify JDBC connect                                                 string
       --connection-manager <class-name> Specify connection manager                                                 class name
       --connection-param-file <properties-file> Specify connection                                                 parameters file
       --driver <class-name> Manually specify JDBC                                                 driver class to use
       --hadoop-home <hdir> Override                                                 $HADOOP_MAPRED_HOME_ARG
       --hadoop-mapred-home <dir> Override                                                 $HADOOP_MAPRED_HOME_ARG
       --help Print usage instructions -P Read password from console    --password <password> Set authentication                                                 password
       --password-alias <password-alias> Credential provider                                                 password alias
       --password-file <password-file> Set authentication                                                 password file path
       --relaxed-isolation Use read-uncommitted                                                 isolation for imports
       --skip-dist-cache Skip copying jars to                                                 distributed cache
       --username <username> Set authentication                                                 username
       --verbose Print more information                                                 while working
    
    # 简单使用
    [hadoop@oradb3 ~]$ sqoop list-databases \
    > --connect jdbc:mysql://localhost:3306 \
    > --username root \
    > --password 123456
    
    # 结果
    information_schema
    mysql
    performance_schema
    slow_query_log
    sys
    test

##### 3.list-tables #####

# 命令帮助
    [hadoop@hadoop000 ~]$ sqoop help list-tables
    usage: sqoop list-tables [GENERIC-ARGS] [TOOL-ARGS]
    
    Common arguments:
       --connect <jdbc-uri> Specify JDBC connect                                                 string
       --connection-manager <class-name> Specify connection manager                                                 class name
       --connection-param-file <properties-file> Specify connection                                                 parameters file
       --driver <class-name> Manually specify JDBC                                                 driver class to use
       --hadoop-home <hdir> Override                                                 $HADOOP_MAPRED_HOME_ARG
       --hadoop-mapred-home <dir> Override                                                 $HADOOP_MAPRED_HOME_ARG
       --help Print usage instructions -P Read password from console    --password <password> Set authentication                                                 password
       --password-alias <password-alias> Credential provider                                                 password alias
       --password-file <password-file> Set authentication                                                 password file path
       --relaxed-isolation Use read-uncommitted                                                 isolation for imports
       --skip-dist-cache Skip copying jars to                                                 distributed cache
       --username <username> Set authentication                                                 username
       --verbose Print more information                                                 while working
    
    # 使用方法
    [hadoop@hadoop000 ~]$ sqoop list-tables \
    > --connect jdbc:mysql://localhost:3306/test \
    > --username root \
    > --password 123456
    
    # 结果
    t_order
    test0001
    test_1013
    test_dyc
    test_tb

##### 4.将mysql导入HDFS中(import) #####

(默认导入当前用户目录下/user/用户名/表名)  
说到这里扩展一个小知识点：  
\* hadoop fs -ls 显示的是当前的用户目录 即/user/hadoop  
hadoop fs -ls / 显示的是HDFS根目录

# 查看命令帮助
    [hadoop@hadoop000 ~]$ sqoop help import
    # 执行import
    [hadoop@hadoop000 ~]$ sqoop import \
    > --connect jdbc:mysql://localhost:3306/test \
    > --username root \
    > --password 123456 \
    > --table students

这时很可能会出现这个错误  
`Exception in thread "main" java.lang.NoClassDefFoundError: org/json/JSONObject`  
这里我们需要导入java-json.jar包 [下载地址][Link 1] 把java-json.jar添加到../sqoop/lib目录下即可

# 再次执行 import导入
    [hadoop@hadoop000 ~]$ sqoop import \
    > --connect jdbc:mysql://localhost:3306/test \
    > --username root \
    > --password 123456 \
    > --table students
    
    18/07/04 13:28:35 INFO sqoop.Sqoop: Running Sqoop version: 1.4.6-cdh5.7.0
    18/07/04 13:28:35 WARN tool.BaseSqoopTool: Setting your password on the command-line is insecure. Consider using -P instead.
    18/07/04 13:28:35 INFO manager.MySQLManager: Preparing to use a MySQL streaming resultset.
    18/07/04 13:28:35 INFO tool.CodeGenTool: Beginning code generation
    18/07/04 13:28:35 INFO manager.SqlManager: Executing SQL statement: SELECT t.* FROM `students` AS t LIMIT 1
    18/07/04 13:28:35 INFO manager.SqlManager: Executing SQL statement: SELECT t.* FROM `students` AS t LIMIT 1
    18/07/04 13:28:35 INFO orm.CompilationManager: HADOOP_MAPRED_HOME is /home/hadoop/app/hadoop-2.6.0-cdh5.7.0
    18/07/04 13:28:37 INFO orm.CompilationManager: Writing jar file: /tmp/sqoop-hadoop/compile/3024b8df04f623e8c79ed9b5b30ace75/students.jar
    18/07/04 13:28:37 WARN manager.MySQLManager: It looks like you are importing from mysql.
    18/07/04 13:28:37 WARN manager.MySQLManager: This transfer can be faster! Use the --direct
    18/07/04 13:28:37 WARN manager.MySQLManager: option to exercise a MySQL-specific fast path.
    18/07/04 13:28:37 INFO manager.MySQLManager: Setting zero DATETIME behavior to convertToNull (mysql)
    18/07/04 13:28:37 INFO mapreduce.ImportJobBase: Beginning import of students
    18/07/04 13:28:38 INFO Configuration.deprecation: mapred.jar is deprecated. Instead, use mapreduce.job.jar
    18/07/04 13:28:39 INFO Configuration.deprecation: mapred.map.tasks is deprecated. Instead, use mapreduce.job.maps
    18/07/04 13:28:39 INFO client.RMProxy: Connecting to ResourceManager at /0.0.0.0:8032
    18/07/04 13:28:41 INFO db.DBInputFormat: Using read commited transaction isolation
    18/07/04 13:28:41 INFO db.DataDrivenDBInputFormat: BoundingValsQuery: SELECT MIN(`id`), MAX(`id`) FROM `students`
    18/07/04 13:28:41 INFO db.IntegerSplitter: Split size: 0; Num splits: 4 from: 1001 to: 1003
    18/07/04 13:28:41 INFO mapreduce.JobSubmitter: number of splits:3
    18/07/04 13:28:42 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1530598609758_0015
    18/07/04 13:28:42 INFO impl.YarnClientImpl: Submitted application application_1530598609758_0015
    18/07/04 13:28:42 INFO mapreduce.Job: The url to track the job: http://oradb3:8088/proxy/application_1530598609758_0015/
    18/07/04 13:28:42 INFO mapreduce.Job: Running job: job_1530598609758_0015
    18/07/04 13:28:52 INFO mapreduce.Job: Job job_1530598609758_0015 running in uber mode : false
    18/07/04 13:28:52 INFO mapreduce.Job:  map 0% reduce 0%
    18/07/04 13:28:58 INFO mapreduce.Job:  map 33% reduce 0%
    18/07/04 13:28:59 INFO mapreduce.Job:  map 67% reduce 0%
    18/07/04 13:29:00 INFO mapreduce.Job:  map 100% reduce 0%
    18/07/04 13:29:00 INFO mapreduce.Job: Job job_1530598609758_0015 completed successfully
    18/07/04 13:29:00 INFO mapreduce.Job: Counters: 30
    ...
    18/07/04 13:29:00 INFO mapreduce.ImportJobBase: Transferred 40 bytes in 21.3156 seconds (1.8766 bytes/sec)
    18/07/04 13:29:00 INFO mapreduce.ImportJobBase: Retrieved 3 records.
    # 生成的日志信息大家一定要好好理解
    # 查看HDFS上的文件
    [hadoop@hadoop000 ~]$ hadoop fs -ls /user/hadoop/students
    Found 4 items
    -rw-r--r--   1 hadoop supergroup          0 2018-07-04 13:28 /user/hadoop/students/_SUCCESS
    -rw-r--r--   1 hadoop supergroup         13 2018-07-04 13:28 /user/hadoop/students/part-m-00000
    -rw-r--r--   1 hadoop supergroup         13 2018-07-04 13:28 /user/hadoop/students/part-m-00001
    -rw-r--r--   1 hadoop supergroup         14 2018-07-04 13:28 /user/hadoop/students/part-m-00002
    [hadoop@hadoop000 ~]$ hadoop fs -cat /user/hadoop/students/"part*"
    1001,lodd,23
    1002,sdfs,21
    1003,sdfsa,24

我们还可以加一些其他参数 使导入过程更加可控

> `-m` 指定启动map进程个数，默认是4个  
> `--delete-target-dir` 删除目标目录  
> `--mapreduce-job-name` 指定mapreduce的job的名字  
> `--target-dir` 导入到指定目录  
> `--fields-terminated-by` 指定字段之间的分隔符  
> `--null-string` 含义是 string类型的字段，当Value是NULL，替换成指定的字符  
> `--null-non-string` 含义是非string类型的字段，当Value是NULL，替换成指定字符  
> `--columns` 导入表中的部分字段  
> `--where` 按条件导入数据  
> `--query` 按照sql语句进行导入 使用–query关键字，就不能使用–table和–columns  
> `--options-file` 在文件中执行

# 执行导入
    [hadoop@hadoop000 ~]$ sqoop import \
    > --connect jdbc:mysql://localhost:3306/test \
    > --username root --password 123456 \
    > --mapreduce-job-name FromMySQL2HDFS \
    > --delete-target-dir \
    > --table students \
    > -m 1
    
    # HDFS中查看
    [hadoop@hadoop000 ~]$ hadoop fs -ls /user/hadoop/students              
    Found 2 items
    -rw-r--r-- 1 hadoop supergroup 0 2018-07-04 13:53 /user/hadoop/students/_SUCCESS
    -rw-r--r-- 1 hadoop supergroup 40 2018-07-04 13:53 /user/hadoop/students/part-m-00000
    [hadoop@oradb3 ~]$ hadoop fs -cat /user/hadoop/students/"part*"
    1001,lodd,23
    1002,sdfs,21
    1003,sdfsa,24

# 使用where 参数
    [hadoop@hadoop000 ~]$ sqoop import \
    > --connect jdbc:mysql://localhost:3306/test \
    > --username root --password 123456 \
    > --table students \
    > --mapreduce-job-name FromMySQL2HDFS2 \
    > --delete-target-dir \
    > --fields-terminated-by '\t' \
    > -m 1 \
    > --null-string 0 \
    > --columns "name" \
    > --target-dir STU_COLUMN_WHERE \
    > --where 'id<1002'
    
    # HDFS 结果
    [hadoop@hadoop000 ~]$ hadoop fs -cat STU_COLUMN_WHERE/"part*"
    lodd

# 使用query 参数
    [hadoop@hadoop000 ~]$ sqoop import \
    > --connect jdbc:mysql://localhost:3306/test \
    > --username root --password 123456 \
    > --mapreduce-job-name FromMySQL2HDFS3 \
    > --delete-target-dir \
    > --fields-terminated-by '\t' \
    > -m 1 \
    > --null-string 0 \
    > --target-dir STU_COLUMN_QUERY \
    > --query "select * from students where id>1001 and \$CONDITIONS"
    
    # HDFS查看
    [hadoop@hadoop000 ~]$ hadoop fs -cat STU_COLUMN_QUERY/"part*"
    1002    sdfs    21
    1003    sdfsa   24

# 使用options-file参数
    [hadoop@hadoop000 ~]$ vi sqoop-import-hdfs.txt
    import
    --connect
    jdbc:mysql://localhost:3306/test
    --username
    root
    --password
    123456
    --table
    students
    --target-dir
    STU_option_file
    # 执行导入
    [hadoop@hadoop000 ~]$ sqoop --options-file /home/hadoop/sqoop-import-hdfs.txt
    # HDFS查看
    [hadoop@hadoop000 ~]$ hadoop fs -cat STU_option_file/"part*"
    1001,lodd,23
    1002,sdfs,21
    1003,sdfsa,24

##### 5.eval #####

查看帮助命令对与该命令的解释为： Evaluate a SQL statement and display the results，也就是说执行一个SQL语句并查询出结果。

# 查看命令帮助
    [hadoop@hadoop000 ~]$ sqoop help eval
    usage: sqoop eval [GENERIC-ARGS] [TOOL-ARGS]
    
    Common arguments:
       --connect <jdbc-uri> Specify JDBC connect                                                 string
       --connection-manager <class-name> Specify connection manager                                                 class name
       --connection-param-file <properties-file> Specify connection                                                 parameters file
       --driver <class-name> Manually specify JDBC                                                 driver class to use
       --hadoop-home <hdir> Override                                                 $HADOOP_MAPRED_HOME_ARG
       --hadoop-mapred-home <dir> Override                                                 $HADOOP_MAPRED_HOME_ARG
       --help Print usage instructions -P Read password from console    --password <password> Set authentication                                                 password
       --password-alias <password-alias> Credential provider                                                 password alias
       --password-file <password-file> Set authentication                                                 password file path
       --relaxed-isolation Use read-uncommitted                                                 isolation for imports
       --skip-dist-cache Skip copying jars to                                                 distributed cache
       --username <username> Set authentication                                                 username
       --verbose Print more information                                                 while working
    
    SQL evaluation arguments:
    -e,--query <statement> Execute 'statement' in SQL and exit # 执行
    [hadoop@hadoop000 ~]$ sqoop eval \
    > --connect jdbc:mysql://localhost:3306/test \
    > --username root --password 123456 \
    > --query "select * from students"
    
    18/07/04 14:28:44 INFO sqoop.Sqoop: Running Sqoop version: 1.4.6-cdh5.7.0
    18/07/04 14:28:44 WARN tool.BaseSqoopTool: Setting your password on the command-line is insecure. Consider using -P instead.
    18/07/04 14:28:44 INFO manager.MySQLManager: Preparing to use a MySQL streaming resultset.
    ---------------------------------------------------- | id          | name                 | age         | 
    ---------------------------------------------------- | 1001        | lodd                 | 23          | 
    | 1002        | sdfs                 | 21          | 
    | 1003        | sdfsa                | 24          | 
    ----------------------------------------------------

##### 6.export (HDFS数据导出到MySQL或Hive中的数据导入到MySQL) #####

常用参数：

> `--table` 指定导出表的名称  
> `--input-fields-terminated-by` 指定hdfs上文件的分隔符，默认是逗号  
> `--export-dir` 导出数据的目录  
> `--columns` 指定导出的字段

在执行导出语句前mysql要先创建表（不创建表会报错）：

# HDFS原文件
    [hadoop@hadoop000 ~]$ hadoop fs -cat /user/hadoop/students/part-m-00000
    1001,lodd,23
    1002,sdfs,21
    1003,sdfsa,24
    # export导出到mysql
    [hadoop@hadoop000 ~]$ sqoop export \
    > --connect jdbc:mysql://localhost:3306/test \
    > --username root \
    > --password 123456 \
    > --table students_demo \
    > --export-dir /user/hadoop/students/
    
    18/07/04 14:46:20 INFO sqoop.Sqoop: Running Sqoop version: 1.4.6-cdh5.7.0
    18/07/04 14:46:20 WARN tool.BaseSqoopTool: Setting your password on the command-line is insecure. Consider using -P instead.
    18/07/04 14:46:20 INFO manager.MySQLManager: Preparing to use a MySQL streaming resultset.
    18/07/04 14:46:20 INFO tool.CodeGenTool: Beginning code generation
    18/07/04 14:46:21 INFO manager.SqlManager: Executing SQL statement: SELECT t.* FROM `students_demo` AS t LIMIT 1
    18/07/04 14:46:21 INFO manager.SqlManager: Executing SQL statement: SELECT t.* FROM `students_demo` AS t LIMIT 1
    18/07/04 14:46:21 INFO orm.CompilationManager: HADOOP_MAPRED_HOME is /home/hadoop/app/hadoop-2.6.0-cdh5.7.0
    18/07/04 14:46:24 INFO orm.CompilationManager: Writing jar file: /tmp/sqoop-hadoop/compile/fc7b53dd6eef701c0731c7a7c4a4b340/students_demo.jar
    18/07/04 14:46:24 INFO mapreduce.ExportJobBase: Beginning export of students_demo
    18/07/04 14:46:25 INFO Configuration.deprecation: mapred.jar is deprecated. Instead, use mapreduce.job.jar
    18/07/04 14:46:25 INFO Configuration.deprecation: mapred.map.max.attempts is deprecated. Instead, use mapreduce.map.maxattempts
    18/07/04 14:46:26 INFO Configuration.deprecation: mapred.reduce.tasks.speculative.execution is deprecated. Instead, use mapreduce.reduce.speculative
    18/07/04 14:46:26 INFO Configuration.deprecation: mapred.map.tasks.speculative.execution is deprecated. Instead, use mapreduce.map.speculative
    18/07/04 14:46:26 INFO Configuration.deprecation: mapred.map.tasks is deprecated. Instead, use mapreduce.job.maps
    ...
    18/07/04 14:46:55 INFO mapreduce.ExportJobBase: Transferred 672 bytes in 29.3122 seconds (22.9256 bytes/sec)
    18/07/04 14:46:55 INFO mapreduce.ExportJobBase: Exported 3 records.
    
    # mysql中查看
    mysql> select * from students_demo;
    +------+-------+------+
    | id   | name  | age  |
    +------+-------+------+
    | 1001 | lodd  |   23 |
    | 1002 | sdfs  |   21 |
    | 1003 | sdfsa |   24 |
    +------+-------+------+
    3 rows in set (0.00 sec)

如果再导入一次会追加在表中

##### 7.MySQL的中的数据导入到Hive中 #####

常用参数：

> `--create-hive-table` 创建目标表，如果有会报错  
> `--hive-database` 指定hive数据库  
> `--hive-import` 指定导入hive（没有这个条件导入到hdfs中）  
> `--hive-overwrite` 覆盖  
> `--hive-table` 指定hive中表的名字，如果不指定使用导入的表的表名  
> `--hive-partition-key` 指定Hive分区表字段  
> `--hive-partition-value` 指定导入的分区值

首次导入可能会报错如下：  
`18/07/04 15:06:26 ERROR hive.HiveConfig: Could not load org.apache.hadoop.hive.conf.HiveConf. Make sure HIVE_CONF_DIR is set correctly. 18/07/04 15:06:26 ERROR tool.ImportTool: Encountered IOException running import job: java.io.IOException: java.lang.ClassNotFoundException: org.apache.hadoop.hive.conf.HiveConf`  
解决方法：到hive目录的lib下拷贝几个jar包，问题就解决了

# 报错解决方法
    [hadoop@hadoop000 lib]$ pwd
    /home/hadoop/app/hive-1.1.0-cdh5.7.0/lib
    [hadoop@hadoop000 lib]$ cp hive-common-1.1.0-cdh5.7.0.jar /home/hadoop/app/sqoop-1.4.6-cdh5.7.0/lib/
    [hadoop@hadoop000 lib]$ cp hive-shims* /home/hadoop/app/sqoop-1.4.6-cdh5.7.0/lib/

# 报错解决后执行导入
    [hadoop@hadoop000 ~]$ sqoop import \
    > --connect jdbc:mysql://localhost:3306/test \
    > --username root --password 123456 \
    > --table students \
    > --create-hive-table \
    > --hive-database hive \
    > --hive-import \
    > --hive-overwrite \
    > --hive-table stu_import \
    > --mapreduce-job-name FromMySQL2HIVE \
    > --delete-target-dir \
    > --fields-terminated-by '\t' \
    > -m 1 \
    > --null-non-string 0
    
    # Hive中查看
    hive> show tables;
    OK
    stu_import
    Time taken: 0.051 seconds, Fetched: 1 row(s)
    hive> select * from stu_import;
    OK
    1001    lodd    23
    1002    sdfs    21
    1003    sdfsa   24
    Time taken: 0.969 seconds, Fetched: 3 row(s)

*建议：*导入Hive不建议大家使用–create-hive-table参数,建议事先创建好hive表；因为自动创建的表字段类型可能并不是我们想要的。

# 增加partition参数
    [hadoop@hadoop000 ~]$ sqoop import \
    > --connect jdbc:mysql://localhost:3306/test \
    > --username root --password 123456 \
    > --table students \
    > --create-hive-table \
    > --hive-database hive \
    > --hive-import \
    > --hive-overwrite \
    > --hive-table stu_import2 \
    > --mapreduce-job-name FromMySQL2HIVE2 \
    > --delete-target-dir \
    > --fields-terminated-by '\t' \
    > -m 1 \
    > --null-non-string 0 \
    > --hive-partition-key dt \
    > --hive-partition-value "2018-08-08"
    # Hive中查看
    hive> select * from stu_import2;
    OK
    1001    lodd    23      2018-08-08
    1002    sdfs    21      2018-08-08
    1003    sdfsa   24      2018-08-08
    Time taken: 0.192 seconds, Fetched: 3 row(s)

##### 8.sqoop job的使用 #####

sqoop job可以将执行的语句变成一个job，并不是在创建语句的时候执行，你可以查看该job，可以任何时候执行该job，也可以删除job，这样就方便我们进行任务的调度。

> `--create` 创建一个新的job.  
> `--delete` 删除job  
> `--exec` 执行job  
> `--show` 显示job的参数  
> `--list` 列出所有的job

# 创建job
    [hadoop@hadoop000 ~]$ sqoop job --create person_job1 -- import --connect jdbc:mysql://localhost:3306/test \
    > --username root \
    > --password 123456 \
    > --table students_demo \
    > -m 1 \
    > --delete-target-dir
    # 查看job
    [hadoop@hadoop000 ~]$ sqoop job --list
    Available jobs:
      person_job1
    # 执行job 会提示输入mysql root用户密码
    [hadoop@hadoop000 ~]$ sqoop job --exec person_job1
    # HDFS查看
    [hadoop@hadoop000 lib]$ hadoop fs -ls /user/hadoop/students_demo
    Found 2 items
    -rw-r--r--   1 hadoop supergroup          0 2018-07-04 15:34 /user/hadoop/students_demo/_SUCCESS
    -rw-r--r--   1 hadoop supergroup         40 2018-07-04 15:34 /user/hadoop/students_demo/part-m-00000

我们发现执行person\_job的时候，需要输入数据库的密码，怎么样能不输入密码呢  
配置sqoop-site.xml即可解决

# 将sqoop.metastore.client.record.password参数的注释去掉 或者再添加一下
    [hadoop@hadoop000 conf]$ pwd
    /home/hadoop/app/sqoop-1.4.6-cdh5.7.0/conf
    [hadoop@hadoop000 conf]$ vi sqoop-site.xml
      <property>
        <name>sqoop.metastore.client.record.password</name>
        <value>true</value>
        <description>If true, allow saved passwords in the metastore.
        </description>
      </property>

*参考文章：*[https://blog.csdn.net/yu0\_zhang0/article/details/79069251][https_blog.csdn.net_yu0_zhang0_article_details_79069251]

[Link 1]: http://www.java2s.com/Code/Jar/j/Downloadjavajsonjar.htm
[https_blog.csdn.net_yu0_zhang0_article_details_79069251]: https://blog.csdn.net/yu0_zhang0/article/details/79069251