mongoexport和导入工具mongoimport介绍

1.7.1.导出工具mongoexport

Mongodb中的mongoexport工具可以把一个库中的collection导出成JSON格式或CSV格式的文件。可以通过指定的内置参数导出数据项，当然导出的时候可以排序和指定条件。

mongoexport具体用法如下所示：

首先进入mongodb的安装目录bin目录下

Shell代码

[root@iZ25ed9nobgZ 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)
--quiet                               silence all non error diagnostic
messages
--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
--authenticationDatabase arg          user source (defaults to dbname)
--authenticationMechanism arg (=MONGODB-CR)
authentication mechanism
--gssapiServiceName arg (=mongodb)    Service name to use when authenticating
using GSSAPI/Kerberos
--gssapiHostName arg                  Remote host name to use for purpose of
GSSAPI/Kerberos authentication
--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                      each db is in a separate directory
(relevant only if dbpath specified)
--journal                             enable journaling (relevant only if
dbpath specified)
-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 field names - 1 per line
-q [ --query ] arg                    query filter, as a JSON string, e.g.,
'{x:{$gt:1}}'
--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
--forceTableScan                      force a table scan (do not use
$snapshot)
--skip arg (=0)                       documents to skip, default 0
--limit arg (=0)                      limit the numbers of documents
returned, default all
--sort arg                            sort order, as a JSON string, e.g.,
'{x:1}'

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

-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(csv类型必须指定列)

实例：mydb库中存在着一个user集合，集合中数据如下：

Js代码

db.user.find();

{ “_id” : ObjectId(“5625a56a02a19713a37259cc”), “id” : “5” }

{ “_id” : ObjectId(“5625a1d402a19713a37259ca”), “age” : 122, “count” : 100, “scores” : 20, “words” : [ 4, 5, 6 ], “title” : [ “t1” ] }

{ “_id” : ObjectId(“5625baed226e076f3161b848”), “id” : 1, “score” : 6 }

{ “_id” : ObjectId(“5625baed226e076f3161b849”), “id” : null }

{ “_id” : ObjectId(“5625baed226e076f3161b84a”), “id” : 4, “score” : 7 }

{ “_id” : ObjectId(“5625baed226e076f3161b84b”), “id” : 3, “score” : 8 }

{ “_id” : ObjectId(“5625baed226e076f3161b84c”), “id” : 2, “name” : “ksf” }

{ “_id” : ObjectId(“5625d7bb7d1b1fbd265f9c10”), “userid” : “001”, “comment” : [ { “name” : “joe dave”, “size” : 12 }, { “name” : “aa”, “size” : 12 } ] }

{ “_id” : ObjectId(“562616c89f0ba19ca2a584d4”), “userid” : “001” }

{ “_id” : ObjectId(“5627043ddc6a998d44600fd1”), “age” : 10, “words” : [ 4, 5, 1 ] }

{ “_id” : ObjectId(“56270447dc6a998d44600fd2”), “age” : 11, “words” : [ 4, 3, 1 ] }

{ “_id” : ObjectId(“56270450dc6a998d44600fd3”), “age” : 10, “words” : [ 6, 5, 2 ] }

1.直接导出数据到文件中

[root@iZ25ed9nobgZ bin]# ./mongoexport -d mydb -c user -o user.data

connected to: 127.0.0.1

exported 12 records

命令执行完后使用ll命令查看，发现目录下生成了一个user.data的文件

Shell代码

-rw-r–r– 1 root root 1057 Oct 21 16:05 user.data

查看该文件信息，具体信息如下：

Shell代码

more user.data或者 cat user.data
{ "_id" : { "$oid" : "5625a1d402a19713a37259ca" }, "age" : 122, "count" : 100, "scores" : 20, "words" : [ 4, 5, 6 ], "title" : [ "t1" ] }
{ "_id" : { "$oid" : "5625a56a02a19713a37259cc" }, "id" : "5" }
{ "_id" : { "$oid" : "5625baed226e076f3161b848" }, "id" : 1, "score" : 6 }
{ "_id" : { "$oid" : "5625baed226e076f3161b849" }, "id" : null }
{ "_id" : { "$oid" : "5625baed226e076f3161b84a" }, "id" : 4, "score" : 7 }
{ "_id" : { "$oid" : "5625baed226e076f3161b84b" }, "id" : 3, "score" : 8 }
{ "_id" : { "$oid" : "5625baed226e076f3161b84c" }, "id" : 2, "name" : "ksf" }
{ "_id" : { "$oid" : "5625d7bb7d1b1fbd265f9c10" }, "userid" : "001", "comment" : [ { "name" : "joe dave", "size" : 12 }, { "name" : "aa", "size" : 12 } ] }
{ "_id" : { "$oid" : "562616c89f0ba19ca2a584d4" }, "userid" : "001" }
{ "_id" : { "$oid" : "5627043ddc6a998d44600fd1" }, "age" : 10, "words" : [ 4, 5, 1 ] }
{ "_id" : { "$oid" : "56270447dc6a998d44600fd2" }, "age" : 11, "words" : [ 4, 3, 1 ] }
{ "_id" : { "$oid" : "56270450dc6a998d44600fd3" }, "age" : 10, "words" : [ 6, 5, 2 ] }

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：

Shell代码

[root@iZ25ed9nobgZ bin]# ./mongoexport -d mydb -c user --csv -f _id,id -o  user_csv.data
connected to: 127.0.0.1
Invalid BSON object type for CSV output: 10
exported 12 records
[root@iZ25ed9nobgZ bin]# more user_csv.data
_id,id
ObjectID(5625a1d402a19713a37259ca),
ObjectID(5625a56a02a19713a37259cc),"5"
ObjectID(5625baed226e076f3161b848),1.0
ObjectID(5625baed226e076f3161b849),
ObjectID(5625baed226e076f3161b84a),4.0
ObjectID(5625baed226e076f3161b84b),3.0
ObjectID(5625baed226e076f3161b84c),2.0
ObjectID(5625d7bb7d1b1fbd265f9c10),
ObjectID(562616c89f0ba19ca2a584d4),
ObjectID(5627043ddc6a998d44600fd1),
ObjectID(56270447dc6a998d44600fd2),
ObjectID(56270450dc6a998d44600fd3),

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user_csv.data 文件中。

1.7.2.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：

Shell代码

[root@iZ25ed9nobgZ bin]# ./mongoimport --help
Import CSV, TSV or JSON data into MongoDB.

When importing JSON documents, each document must be a separate line of the input file.

Example:
mongoimport --host myhost --db my_cms --collection docs < mydocfile.json

Options:
--help                                produce help message
-v [ --verbose ]                      be more verbose (include multiple times
for more verbosity e.g. -vvvvv)
--quiet                               silence all non error diagnostic
messages
--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
--authenticationDatabase arg          user source (defaults to dbname)
--authenticationMechanism arg (=MONGODB-CR)
authentication mechanism
--gssapiServiceName arg (=mongodb)    Service name to use when authenticating
using GSSAPI/Kerberos
--gssapiHostName arg                  Remote host name to use for purpose of
GSSAPI/Kerberos authentication
--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                      each db is in a separate directory
(relevant only if dbpath specified)
--journal                             enable journaling (relevant only if
dbpath specified)
-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 field 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                          first line in input file is a header
(CSV and TSV only)
--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 16MB.

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

-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

示例：先删除user中的数据，并验证

Js代码

db.user.remove({});

WriteResult({ “nRemoved” : 12 })

db.user.find();

然后再导入上面导出的user.data文件中的内容

Shell代码

[root@iZ25ed9nobgZ bin]# ./mongoimport -d mydb -c user  user.data
connected to: 127.0.0.1
2015-10-21T16:24:46.456+0800 check 9 12
2015-10-21T16:24:46.457+0800 imported 12 objects

查询user集合中的数据.

Js代码

> db.user.find();
{ "_id" : ObjectId("5625a1d402a19713a37259ca"), "age" : 122, "count" : 100, "scores" : 20, "words" : [ 4, 5, 6 ], "title" : [ "t1" ] }
{ "_id" : ObjectId("5625a56a02a19713a37259cc"), "id" : "5" }
{ "_id" : ObjectId("5625baed226e076f3161b848"), "id" : 1, "score" : 6 }
{ "_id" : ObjectId("5625baed226e076f3161b849"), "id" : null }
{ "_id" : ObjectId("5625baed226e076f3161b84a"), "id" : 4, "score" : 7 }
{ "_id" : ObjectId("5625baed226e076f3161b84b"), "id" : 3, "score" : 8 }
{ "_id" : ObjectId("5625baed226e076f3161b84c"), "id" : 2, "name" : "ksf" }
{ "_id" : ObjectId("5625d7bb7d1b1fbd265f9c10"), "userid" : "001", "comment" : [ { "name" : "joe dave", "size" : 12 }, { "name" : "aa", "size" : 12 } ] }
{ "_id" : ObjectId("562616c89f0ba19ca2a584d4"), "userid" : "001" }
{ "_id" : ObjectId("5627043ddc6a998d44600fd1"), "age" : 10, "words" : [ 4, 5, 1 ] }
{ "_id" : ObjectId("56270447dc6a998d44600fd2"), "age" : 11, "words" : [ 4, 3, 1 ] }
{ "_id" : ObjectId("56270450dc6a998d44600fd3"), "age" : 10, "words" : [ 6, 5, 2 ] }

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也是默认的方式，如果要导入CSV格式文件或者csv格式或者tsv中的内容，则需要通过–type参数指定导入格式。