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:\data\student_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:\data\student_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:\data\student_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:\data\student_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
