Mongodb数据导出工具mongoexport和导入工具mongoimport介绍

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一、导出工具mongoexport

Mongodb中的mongoexport工具可以把一个collection导出成JSON格式或CSV格式的文件。可以通过参数指定导出的数据项，也可以根据指定的条件导出数据。mongoexport具体用法如下所示：

 [root@localhost mongodb]# ./bin/mongoexport --help
 Export MongoDB data to CSV, TSV or JSON files.

 options:
   --help                    produce help message
   -v [ --verbose ]          be more verbose (include multiple times for more
                             verbosity e.g. -vvvvv)
   --version                 print the program's version and exit
   -h [ --host ] arg         mongo host to connect to ( <set name>/s1,s2 for
                             sets)
   --port arg                server port. Can also use --host hostname:port
   --ipv6                    enable IPv6 support (disabled by default)
   -u [ --username ] arg     username
   -p [ --password ] arg     password
   --dbpath arg              directly access mongod database files in the given
                             path, instead of connecting to a mongod  server -
                             needs to lock the data directory, so cannot be used
                             if a mongod is currently accessing the same path
   --directoryperdb          if dbpath specified, each db is in a separate
                             directory
   --journal                 enable journaling
   -d [ --db ] arg           database to use
   -c [ --collection ] arg   collection to use (some commands)
   -f [ --fields ] arg       comma separated list of field names e.g. -f
                             name,age
   --fieldFile arg           file with fields names - 1 per line
   -q [ --query ] arg        query filter, as a JSON string
   --csv                     export to csv instead of json
   -o [ --out ] arg          output file; if not specified, stdout is used
   --jsonArray               output to a json array rather than one object per
                             line
   -k [ --slaveOk ] arg (=1) use secondaries for export if available, default
                             true

参数说明：

-h:指明数据库宿主机的IP

-u:指明数据库的用户名

-p:指明数据库的密码

-d:指明数据库的名字

-c:指明collection的名字

-f:指明要导出那些列

-o:指明到要导出的文件名

-q:指明导出数据的过滤条件

 

实例：test库中存在着一个students集合，集合中数据如下：

 > db.students.find()
 { "_id" : ObjectId("5031143350f2481577ea81e5"), "classid" : 1, "age" : 20, "name" : "kobe" }
 { "_id" : ObjectId("5031144a50f2481577ea81e6"), "classid" : 1, "age" : 23, "name" : "nash" }
 { "_id" : ObjectId("5031145a50f2481577ea81e7"), "classid" : 2, "age" : 18, "name" : "james" }
 { "_id" : ObjectId("5031146a50f2481577ea81e8"), "classid" : 2, "age" : 19, "name" : "wade" }
 { "_id" : ObjectId("5031147450f2481577ea81e9"), "classid" : 2, "age" : 19, "name" : "bosh" }
 { "_id" : ObjectId("5031148650f2481577ea81ea"), "classid" : 2, "age" : 25, "name" : "allen" }
 { "_id" : ObjectId("5031149b50f2481577ea81eb"), "classid" : 1, "age" : 19, "name" : "howard" }
 { "_id" : ObjectId("503114a750f2481577ea81ec"), "classid" : 1, "age" : 22, "name" : "paul" }
 { "_id" : ObjectId("503114cd50f2481577ea81ed"), "classid" : 2, "age" : 24, "name" : "shane" }

由上可以看出文档中存在着3个字段：classid、age、name

1.直接导出数据到文件中

 [root@localhost mongodb]# ./bin/mongoexport -d test -c students -o students.dat
 connected to: 127.0.0.1
 exported 9 records

命令执行完后使用ll命令查看，发现目录下生成了一个students.dat的文件

 -rw-r--r-- 1 root root   869 Aug 21 00:05 students.dat

查看该文件信息，具体信息如下：

 [root@localhost mongodb]# cat students.dat
 { "_id" : { "$oid" : "5031143350f2481577ea81e5" }, "classid" : 1, "age" : 20, "name" : "kobe" }
 { "_id" : { "$oid" : "5031144a50f2481577ea81e6" }, "classid" : 1, "age" : 23, "name" : "nash" }
 { "_id" : { "$oid" : "5031145a50f2481577ea81e7" }, "classid" : 2, "age" : 18, "name" : "james" }
 { "_id" : { "$oid" : "5031146a50f2481577ea81e8" }, "classid" : 2, "age" : 19, "name" : "wade" }
 { "_id" : { "$oid" : "5031147450f2481577ea81e9" }, "classid" : 2, "age" : 19, "name" : "bosh" }
 { "_id" : { "$oid" : "5031148650f2481577ea81ea" }, "classid" : 2, "age" : 25, "name" : "allen" }
 { "_id" : { "$oid" : "5031149b50f2481577ea81eb" }, "classid" : 1, "age" : 19, "name" : "howard" }
 { "_id" : { "$oid" : "503114a750f2481577ea81ec" }, "classid" : 1, "age" : 22, "name" : "paul" }
 { "_id" : { "$oid" : "503114cd50f2481577ea81ed" }, "classid" : 2, "age" : 24, "name" : "shane" }

参数说明：

-d:指明使用的库，本例中为test

-c:指明要导出的集合，本例中为students

-o:指明要导出的文件名，本例中为students.dat

从上面的结果可以看出，我们在导出数据时没有显示指定导出样式 ，默认导出了JSON格式的数据。如果我们需要导出CSV格式的数据，则需要使用--csv参数，具体如下所示：

 [root@localhost mongodb]# ./bin/mongoexport -d test -c students --csv -f classid,name,age -o students_csv.dat
 connected to: 127.0.0.1
 exported 9 records
 [root@localhost mongodb]# cat students_csv.dat
 classid,name,age
 1.0,"kobe",20.0
 1.0,"nash",23.0
 2.0,"james",18.0
 2.0,"wade",19.0
 2.0,"bosh",19.0
 2.0,"allen",25.0
 1.0,"howard",19.0
 1.0,"paul",22.0
 2.0,"shane",24.0
 [root@localhost mongodb]#

参数说明：

-csv：指明要导出为csv格式

-f：指明需要导出classid、name、age这3列的数据

由上面结果可以看出，mongoexport成功地将数据根据csv格式导出到了students_csv.dat文件中。

 

二、导入工具mongoimport

Mongodb中的mongoimport工具可以把一个特定格式文件中的内容导入到指定的collection中。该工具可以导入JSON格式数据，也可以导入CSV格式数据。具体使用如下所示：

 [root@localhost mongodb]# ./bin/mongoimport --help
 options:
   --help                  produce help message
   -v [ --verbose ]        be more verbose (include multiple times for more
                           verbosity e.g. -vvvvv)
   --version               print the program's version and exit
   -h [ --host ] arg       mongo host to connect to ( <set name>/s1,s2 for sets)
   --port arg              server port. Can also use --host hostname:port
   --ipv6                  enable IPv6 support (disabled by default)
   -u [ --username ] arg   username
   -p [ --password ] arg   password
   --dbpath arg            directly access mongod database files in the given
                           path, instead of connecting to a mongod  server -
                           needs to lock the data directory, so cannot be used
                           if a mongod is currently accessing the same path
   --directoryperdb        if dbpath specified, each db is in a separate
                           directory
   --journal               enable journaling
   -d [ --db ] arg         database to use
   -c [ --collection ] arg collection to use (some commands)
   -f [ --fields ] arg     comma separated list of field names e.g. -f name,age
   --fieldFile arg         file with fields names - 1 per line
   --ignoreBlanks          if given, empty fields in csv and tsv will be ignored
   --type arg              type of file to import.  default: json (json,csv,tsv)
   --file arg              file to import from; if not specified stdin is used
   --drop                  drop collection first
   --headerline            CSV,TSV only - use first line as headers
   --upsert                insert or update objects that already exist
   --upsertFields arg      comma-separated fields for the query part of the
                           upsert. You should make sure this is indexed
   --stopOnError           stop importing at first error rather than continuing
   --jsonArray             load a json array, not one item per line. Currently
                           limited to 4MB.

参数说明：

-h:指明数据库宿主机的IP

-u:指明数据库的用户名

-p:指明数据库的密码

-d:指明数据库的名字

-c:指明collection的名字

-f:指明要导入那些列

 

示例：先删除students中的数据，并验证

 > db.students.remove()
 > db.students.find()
 >

然后再导入上面导出的students.dat文件中的内容

 [root@localhost mongodb]# ./bin/mongoimport -d test -c students students.dat
 connected to: 127.0.0.1
 imported 9 objects
 [root@localhost mongodb]#

参数说明：

-d:指明数据库名，本例中为test

-c:指明collection名，本例中为students

students.dat：导入的文件名

查询students集合中的数据

 > db.students.find()
 { "_id" : ObjectId("5031143350f2481577ea81e5"), "classid" : 1, "age" : 20, "name" : "kobe" }
 { "_id" : ObjectId("5031144a50f2481577ea81e6"), "classid" : 1, "age" : 23, "name" : "nash" }
 { "_id" : ObjectId("5031145a50f2481577ea81e7"), "classid" : 2, "age" : 18, "name" : "james" }
 { "_id" : ObjectId("5031146a50f2481577ea81e8"), "classid" : 2, "age" : 19, "name" : "wade" }
 { "_id" : ObjectId("5031147450f2481577ea81e9"), "classid" : 2, "age" : 19, "name" : "bosh" }
 { "_id" : ObjectId("5031148650f2481577ea81ea"), "classid" : 2, "age" : 25, "name" : "allen" }
 { "_id" : ObjectId("5031149b50f2481577ea81eb"), "classid" : 1, "age" : 19, "name" : "howard" }
 { "_id" : ObjectId("503114a750f2481577ea81ec"), "classid" : 1, "age" : 22, "name" : "paul" }
 { "_id" : ObjectId("503114cd50f2481577ea81ed"), "classid" : 2, "age" : 24, "name" : "shane" }
 >

证明数据导入成功

上面演示的是导入JSON格式的文件中的内容，如果要导入CSV格式文件中的内容，则需要通过--type参数指定导入格式，具体如下所示：

先删除数据

 > db.students.remove()
 > db.students.find()
 >

再导入之前导出的students_csv.dat文件

 [root@localhost mongodb]# ./bin/mongoimport -d test -c students --type csv --headerline --file students_csv.dat
 connected to: 127.0.0.1
 imported 10 objects
 [root@localhost mongodb]#

参数说明：

-type:指明要导入的文件格式

-headerline:指明第一行是列名，不需要导入

-file：指明要导入的文件

查询students集合，验证导入是否成功：

 > db.students.find()
 { "_id" : ObjectId("503266029355c632cd118ad8"), "classid" : 1, "name" : "kobe", "age" : 20 }
 { "_id" : ObjectId("503266029355c632cd118ad9"), "classid" : 1, "name" : "nash", "age" : 23 }
 { "_id" : ObjectId("503266029355c632cd118ada"), "classid" : 2, "name" : "james", "age" : 18 }
 { "_id" : ObjectId("503266029355c632cd118adb"), "classid" : 2, "name" : "wade", "age" : 19 }
 { "_id" : ObjectId("503266029355c632cd118adc"), "classid" : 2, "name" : "bosh", "age" : 19 }
 { "_id" : ObjectId("503266029355c632cd118add"), "classid" : 2, "name" : "allen", "age" : 25 }
 { "_id" : ObjectId("503266029355c632cd118ade"), "classid" : 1, "name" : "howard", "age" : 19 }
 { "_id" : ObjectId("503266029355c632cd118adf"), "classid" : 1, "name" : "paul", "age" : 22 }
 { "_id" : ObjectId("503266029355c632cd118ae0"), "classid" : 2, "name" : "shane", "age" : 24 }
 >

说明已经导入成功