原文链接：http://chenzhou123520.iteye.com/blog/1641319
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 ( /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 ( /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
阅读(7652) | 评论(0) | 转发(0) |
