Mongodb數據導出工具mongoexport和導入工具mongoimport介紹

1、導出工具mongoexport

Mongodb中的mongoexport工具能夠把一個collection導出成JSON格式或CSV格式的文件。能夠經過參數指定導出的數據項，也能夠根據指定的條件導出數據。mongoexport具體用法以下所示：

[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

參數說明：

-h:指明數據庫宿主機的IP

-u:指明數據庫的用戶名

-p:指明數據庫的密碼

-d:指明數據庫的名字

-c:指明collection的名字

-f:指明要導出那些列

-o:指明到要導出的文件名

-q:指明導出數據的過濾條件

實例：test庫中存在着一個students集合，集合中數據以下：

> 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" }

由上能夠看出文檔中存在着3個字段：classid、age、name

1.直接導出數據到文件中

 

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

命令執行完後使用ll命令查看，發現目錄下生成了一個students.dat的文件

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

查看該文件信息，具體信息以下：

[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" }

參數說明：

-d:指明使用的庫，本例中爲test

-c:指明要導出的集合，本例中爲students

-o:指明要導出的文件名，本例中爲students.dat

從上面的結果能夠看出，咱們在導出數據時沒有顯示指定導出樣式 ，默認導出了JSON格式的數據。若是咱們須要導出CSV格式的數據，則須要使用--csv參數，具體以下所示：

[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]#

參數說明：

-csv：指明要導出爲csv格式

-f：指明須要導出classid、name、age這3列的數據

由上面結果能夠看出，mongoexport成功地將數據根據csv格式導出到了students_csv.dat文件中。

2、導入工具mongoimport

Mongodb中的mongoimport工具能夠把一個特定格式文件中的內容導入到指定的collection中。該工具能夠導入JSON格式數據，也能夠導入CSV格式數據。具體使用以下所示：

[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.

參數說明：

-h:指明數據庫宿主機的IP

-u:指明數據庫的用戶名

-p:指明數據庫的密碼

-d:指明數據庫的名字

-c:指明collection的名字

-f:指明要導入那些列

示例：先刪除students中的數據，並驗證

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

而後再導入上面導出的students.dat文件中的內容

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

參數說明：

-d:指明數據庫名，本例中爲test

-c:指明collection名，本例中爲students

students.dat：導入的文件名

查詢students集合中的數據

> 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" }
>

證實數據導入成功

上面演示的是導入JSON格式的文件中的內容，若是要導入CSV格式文件中的內容，則須要經過--type參數指定導入格式，具體以下所示：

先刪除數據

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

再導入以前導出的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]#

參數說明：

-type:指明要導入的文件格式

-headerline:指明第一行是列名，不須要導入

-file：指明要導入的文件

查詢students集合，驗證導入是否成功：

> 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 }
>

說明已經導入成功