[Hadoop]Sqoop 1.4.2中文文档（二）之数据导出

一、sqoop-export
相关参数：

usage: sqoop export [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 <dir>                          Override $HADOOP_HOME
   --help                                       Print usage instructions
-P                                              Read password from console
   --password <password>                        Set authentication
                                                password
   --username <username>                        Set authentication
                                                username
   --verbose                                    Print more information
                                                while working

Export control arguments:
   --batch                         Indicates underlying statements to be
                                   executed in batch mode
   --clear-staging-table           Indicates that any data in staging
                                   table can be deleted
   --direct                        Use direct export fast path
   --export-dir <dir>              HDFS source path for the export
-m,--num-mappers <n>               Use 'n' map tasks to export in parallel
   --staging-table <table-name>    Intermediate staging table
   --table <table-name>            Table to populate
   --update-key <key>              Update records by specified key column
   --update-mode <mode>            Specifies how updates are performed
                                   when new rows are found with
                                   non-matching keys in database

Input parsing arguments:
   --input-enclosed-by <char>               Sets a required field encloser
   --input-escaped-by <char>                Sets the input escape
                                            character
   --input-fields-terminated-by <char>      Sets the input field separator
   --input-lines-terminated-by <char>       Sets the input end-of-line
                                            char
   --input-optionally-enclosed-by <char>    Sets a field enclosing
                                            character

Output line formatting arguments:
   --enclosed-by <char>               Sets a required field enclosing
                                      character
   --escaped-by <char>                Sets the escape character
   --fields-terminated-by <char>      Sets the field separator character
   --lines-terminated-by <char>       Sets the end-of-line character
   --mysql-delimiters                 Uses MySQL's default delimiter set:
                                      fields: ,  lines: \n  escaped-by: \
                                      optionally-enclosed-by: '
   --optionally-enclosed-by <char>    Sets a field enclosing character

Code generation arguments:
   --bindir <dir>                        Output directory for compiled
                                         objects
   --class-name <name>                   Sets the generated class name.
                                         This overrides --package-name.
                                         When combined with --jar-file,
                                         sets the input class.
   --input-null-non-string <null-str>    Input null non-string
                                         representation
   --input-null-string <null-str>        Input null string representation
   --jar-file <file>                     Disable code generation; use
                                         specified jar
   --map-column-java <arg>               Override mapping for specific
                                         columns to java types
   --null-non-string <null-str>          Null non-string representation
   --null-string <null-str>              Null string representation
   --outdir <dir>                        Output directory for generated
                                         code
   --package-name <name>                 Put auto-generated classes in
                                         this package

Generic Hadoop command-line arguments:
(must preceed any tool-specific arguments)
Generic options supported are
-conf <configuration file>     specify an application configuration file
-D <property=value>            use value for given property
-fs <local|namenode:port>      specify a namenode
-jt <local|jobtracker:port>    specify a job tracker
-files <comma separated list of files>    specify comma separated files to be copied to the map reduce cluster
-libjars <comma separated list of jars>    specify comma separated jar files to include in the classpath.
-archives <comma separated list of archives>    specify comma separated archives to be unarchived on the compute machines.

从这里我们可以看到，大部分的参数使用是与导入相同的，只有少部分是导出专用的。

既然导入和导出的道理都是相同的，那么我就不按照自己的理解把官网上的话变成自己的话了。直接看一个例子：（这里如果你不懂，请把数据导入完整看完）

$ sqoop export --connect jdbc:mysql://db.example.com/foo --table bar  \
    --export-dir /results/bar_data