进入bin目录下 使用./mongoexport --help可以查看帮助。
其中
--authenticationDatabase 是需要验证的数据库，这里我开启了验证， 验证的是超级用户。
--db，--collection 是需要访问的数据库和集合
--type 不指定的情况是json
--out 保存的位置
--fields 是需要返回的字段
例子:
/usr/local/mongodb3.3/bin$ ./mongoexport --host 192.168.9.1 --port 27017 --username thewindkee --password mypd --authenticationDatabase admin --db mydb --collection mycl --type csv --out ~/abc.csv -q'{"name":"gkwind","type":1}' --fields 'name,type'
附：
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) ssl options: --ssl connect to a mongod or mongos that has ssl enabled --sslCAFile= the .pem file containing the root certificate chain from the certificate authority --sslPEMKeyFile= the .pem file containing the certificate and key --sslPEMKeyPassword= the password to decrypt the sslPEMKeyFile, if necessary --sslCRLFile= the .pem file containing the certificate revocation list --sslAllowInvalidCertificates bypass the validation for server certificates --sslAllowInvalidHostnames bypass the validation for server name --sslFIPSMode use FIPS mode of the installed openssl library 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}'
