Mongo的导出工具mongoexport介绍

需求介绍：将mongodb中的数据以文件的方式导出：json或cvs格式

mongo 提供了mongoexport的工具，可以实现将库中的数据以json或cvs的格式输出到文件中。mongoexport位于mongo安装位置中的bin/目录下。

mongoexport具体用法如下所示：

1. 使用help查看参数说明

E:data                                                                                 
λ mongoexport --help                                                                    
Usage:                                                                                  
  mongoexport <options>                                                                 
                                                                                        
Export data from MongoDB in CSV or JSON format.                                         
                                                                                        
See http://docs.mongodb.org/manual/reference/program/mongoexport/ for more information. 
                                                                                        
general options:                                                                        
      /help                      print usage                                            
      /version                   print the tool version and exit                        
                                                                                        
verbosity options:                                                                      
  /v, /verbose                   more detailed log output (include multiple             
                                 times for more verbosity, e.g. -vvvvv)                 
      /quiet                     hide all log output                                    
                                                                                        
connection options:                                                                     
  /h, /host:                     mongodb host to connect to                             
                                 (setname/host1,host2 for replica sets)                 
      /port:                     server port (can also use --host hostname:port)        
                                                                                        
authentication options:                                                                 
  /u, /username:                 username for authentication                            
  /p, /password:                 password for authentication                            
      /authenticationDatabase:   database that holds the user's credentials             
      /authenticationMechanism:  authentication mechanism to use                        
                                                                                        
namespace options:                                                                      
  /d, /db:                       database to use                                        
  /c, /collection:               collection to use                                      
                                                                                        
output options:                                                                         
  /f, /fields:                   comma separated list of field names (required          
                                 for exporting CSV) e.g. -f "name,age"                  
      /fieldFile:                file with field names - 1 per line                     
      /type:                     the output format, either json or csv                  
                                 (defaults to 'json')                                   
  /o, /out:                      output file; if not specified, stdout is used          
      /jsonArray                 output to a JSON array rather than one object          
                                 per line                                               
      /pretty                    output JSON formatted to be human-readable             
                                                                                        
querying options:                                                                       
  /q, /query:                    query filter, as a JSON string, e.g.,                  
                                 '{x:{$gt:1}}'                                          
  /k, /slaveOk                   allow secondary reads if available (default            
                                 true)                                                  
      /forceTableScan            force a table scan (do not use $snapshot)              
      /skip:                     number of documents to skip                            
      /limit:                    limit the number of documents to export                
      /sort:                     sort order, as a JSON string, e.g. '{x:1}'             

2. 用例说明:

将info库中student的所有信息以json格式导出到student_json.dat数据文件中

mongoexport -h 127.0.0.1 -u root -p 12345 -d info -c student --type=json -o E:datastudent_json.dat

输出：

{
    "id": 123,
    "name": "张三",
    "age": 12
}
{
    "id": 124,
    "name": "李四",
    "age": 15
}

将info库中student的id,name信息以json格式导出到student_json.dat数据文件中，并且限定“行数”是1

mongoexport -h 127.0.0.1 -u root -p 12345 -d info -c student --type=json -f id,name --limit=1 -o E:datastudent_json.dat

输出：

{
    "id": 1,
    "name": "张三"
}

将info库中student的所有信息以cvs格式导出到student_cvs.dat数据文件中

mongoexport -h 127.0.0.1 -u root -p 12345 -d info -c student --type=cvs  -o E:datastudent_cvs.dat

输出：

123,"张三",12
124,"李四",15

将info库student“表”的name=张三的信息以cvs格式导出到student_cvs.dat数据文件中

mongoexport -h 127.0.0.1 -u root -p 12345 -d info -c student --type=cvs -q{"name":"张三"} -o E:datastudent_cvs.dat

输出：

123,"张三",12

 注意：

a. --type=json 只是控制每一条“记录”是json格式，而整体的输出文件不是json 。如果想要控制整体的文件数据格式是json数组，则需要使用--jsonArray 参数控制

扩展：

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：

E:data
λ mongoimport --help
Usage:
  mongoimport <options> <file>

Import CSV, TSV or JSON data into MongoDB. If no file is provided, mongoimport reads from stdin.

See http://docs.mongodb.org/manual/reference/program/mongoimport/ for more information.

general options:
      /help                      print usage
      /version                   print the tool version and exit

verbosity options:
  /v, /verbose                   more detailed log output (include multiple
                                 times for more verbosity, e.g. -vvvvv)
      /quiet                     hide all log output

connection options:
  /h, /host:                     mongodb host to connect to
                                 (setname/host1,host2 for replica sets)
      /port:                     server port (can also use --host hostname:port)

authentication options:
  /u, /username:                 username for authentication
  /p, /password:                 password for authentication
      /authenticationDatabase:   database that holds the user's credentials
      /authenticationMechanism:  authentication mechanism to use

namespace options:
  /d, /db:                       database to use
  /c, /collection:               collection to use

input options:
  /f, /fields:                   comma separated list of field names, e.g. -f
                                 name,age
      /fieldFile:                file with field names - 1 per line
      /file:                     file to import from; if not specified, stdin
                                 is used
      /headerline                use first line in input source as the field
                                 list (CSV and TSV only)
      /jsonArray                 treat input source as a JSON array
      /type:                     input format to import: json, csv, or tsv
                                 (defaults to 'json')

ingest options:
      /drop                      drop collection before inserting documents
      /ignoreBlanks              ignore fields with empty values in CSV and TSV
      /maintainInsertionOrder    insert documents in the order of their
                                 appearance in the input source
  /j, /numInsertionWorkers:      number of insert operations to run
                                 concurrently (defaults to 1)
      /stopOnError               stop importing at first insert/upsert error
      /upsert                    insert or update objects that already exist
      /upsertFields:             comma-separated fields for the query part of
                                 the upsert
      /writeConcern:             write concern options e.g. --writeConcern
                                 majority, --writeConcern '{w: 3, wtimeout:
                                 500, fsync: true, j: true}' (defaults to
                                 'majority')

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

mongoimport -d test -c students students.dat 
connected to: 127.0.0.1
imported 9 objects

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

mongoimport -d test -c students --type csv --headerline --file students_csv.dat 
connected to: 127.0.0.1
imported 10 objects

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

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