折腾：
【已解决】把本地mp3文件存入在线Mongo中且填写meta信息
期间：
<code>> db.fs.files.findOne()
{
"_id" : ObjectId("5b20d5ec7f4d384006e91f18"),
"contentType" : "audio/mpeg",
"chunkSize" : 261120,
"metadata" : {
"song" : {
"singers" : [ ]
},
"fitAgeStart" : 3,
"topics" : [
"Wisdom",
"Animals",
"Villain"
],
"storybook" : {
"publisher" : "Mathew Price",
"isFiction" : "是",
"lexileIndex" : "",
"awards" : "",
"authors" : [
"Atsuko Morozumi"
],
"foreignCountry" : "英国"
},
"keywords" : {
"fromName" : [
"go away Mr Wolf",
"Mr wolf",
"Go away",
"wolf"
],
"other" : [ ],
"fromContent" : [
"knock!",
"go away",
"Mr Wolf",
"quickly shut the door"
]
},
"name" : "Go away, Mr Wolf",
"resourceType" : "storybook",
"mainActors" : [
"three little pigs",
"Mr.Wolf"
],
"contentAbstract" : "一个教小朋友警惕坏人的故事，狼先生扮成各种样子前来敲小猪家的们，3只小猪识别了狼的真面目，把门关上不让狼进来，一直到爸爸回来把发生的事情告诉爸爸听。",
"isSeries" : false,
"series" : {
"number" : 0,
"name" : ""
},
"fitAgeEnd" : 4,
"fileInfo" : {
"isAudio" : true,
"contentType" : "audio/mpeg",
"name" : "Go away, Mr Wolf.mp3",
"suffix" : "mp3"
}
},
"filename" : "Go away, Mr Wolf.mp3",
"length" : 1613790,
"uploadDate" : ISODate("2018-06-13T08:29:32.493Z"),
"md5" : "3fa28e2ef5e7e56e15f797cd169845cc"
}
</code>但是每次
db.fs.files.findOne()
只能输出第一个
想要多找几个gridfs的file看看信息
想要稍微多输出几个
mongo gridfs find several
mongo find several
Limit the Number of Documents to Return
是我要的
<code>> db.fs.files.find().limit(3)
{ "_id" : ObjectId("5b20d5ec7f4d384006e91f18"), "contentType" : "audio/mpeg", "chunkSize" : 261120, "metadata" : { "song" : { "singers" : [ ] }, "fitAgeStart" : 3, "topics" : [ "Wisdom", "Animals", "Villain" ], "storybook" : { "publisher" : "Mathew Price", "isFiction" : "是", "lexileIndex" : "", "awards" : "", "authors" : [ "Atsuko Morozumi" ], "foreignCountry" : "英国" }, "keywords" : { "fromName" : [ "go away Mr Wolf", "Mr wolf", "Go away", "wolf" ], "other" : [ ], "fromContent" : [ "knock!", "go away", "Mr Wolf", "quickly shut the door" ] }, "name" : "Goaway, Mr Wolf", "resourceType" : "storybook", "mainActors" : [ "three little pigs", "Mr.Wolf" ], "contentAbstract" : "一个教小朋友警惕坏人的故事，狼先生扮成各种样子前来敲小猪家的们，3只小猪识别了狼的真面目，把门关上不让狼进来，一直到爸爸回来把发生的事情告诉爸爸听。", "isSeries" :false, "series" : { "number" : 0, "name" : "" }, "fitAgeEnd" : 4, "fileInfo" : { "isAudio" : true, "contentType" : "audio/mpeg", "name" : "Go away, Mr Wolf.mp3", "suffix" : "mp3" } }, "filename" : "Go away, Mr Wolf.mp3", "length" : 1613790, "uploadDate" : ISODate("2018-06-13T08:29:32.493Z"), "md5" : "3fa28e2ef5e7e56e15f797cd169845cc" }
{ "_id" : ObjectId("5b20d5ec7f4d384006e91f20"), "contentType" : "audio/mpeg", "chunkSize" : 261120, "metadata" : { "song" : { "singers" : [ ] }, "fitAgeStart" : 0, "topics" : [ ], "storybook" : { "publisher" : "", "isFiction" : "未知", "lexileIndex" : "", "awards" : "", "authors" : [ "Robert Munsch" ], "foreignCountry" : "" }, "keywords" : { "fromName" : [ "Love you", "Love", "forever" ], "other" : [ ], "fromContent" :[ ] }, "name" : "Love You Forever", "resourceType" : "storybook", "mainActors" : [ ], "contentAbstract" : "", "isSeries" : false, "series" :{ "number" : 0, "name" : "" }, "fitAgeEnd" : 0, "fileInfo" : { "isAudio" : true, "contentType" : "audio/mpeg", "name" : "Love You Forever.mp3", "suffix" : "mp3" } }, "filename" : "Love You Forever.mp3", "length" : 2324504, "uploadDate" : ISODate("2018-06-13T08:29:32.611Z"), "md5" : "12bd627611ad4b0f8806c7182414c155" }
{ "_id" : ObjectId("5b20d5ec7f4d384006e91f2a"), "contentType" : "audio/mpeg", "chunkSize" : 261120, "metadata" : { "song" : { "singers" : [ ] }, "fitAgeStart" : 0, "topics" : [ ], "storybook" : { "publisher" : "", "isFiction" : "未知", "lexileIndex" : "", "awards" : "", "authors" : [ "Anthony Brown" ], "foreignCountry" : "" }, "keywords" : { "fromName" : [ "I like", "book" ], "other" : [ ], "fromContent" : [ ] }, "name" : "I like books", "resourceType" : "storybook", "mainActors" : [ ], "contentAbstract" : "", "isSeries" : false, "series" : { "number" : 0, "name" : "" }, "fitAgeEnd" : 0, "fileInfo" : { "isAudio" : true, "contentType" : "audio/mpeg", "name" : "I like books.mp3", "suffix" : "mp3" } }, "filename" : "I like books.mp3", "length" : 1679723, "uploadDate" : ISODate("2018-06-13T08:29:32.681Z"), "md5" : "5615c4b2f711a76c400b87f0586e3c4d" }
>
</code>然后再去用：
> db.fs.files.find().limit(10)
找到一个其他类型的，供参考：
<code>{ "_id" : ObjectId("5b20d5ed7f4d384006e91f96"), "contentType" : "application/pdf", "chunkSize" : 261120, "metadata" : { "song" : { "singers": [ ] }, "fitAgeStart" : 5, "topics" : [ "Love", "Animals" ], "storybook" : { "publisher" : "", "isFiction" : "是", "lexileIndex" : "", "awards" : "", "authors" : [ "Jez Alborough" ], "foreignCountry" : "" }, "keywords" : { "fromName" : [ "my Teddy", "where is Teddy", "where Teddy", "Teddy", "where" ], "other" : [ ], "fromContent" : [ ] }, "name" : "Where is my Teddy", "resourceType" : "storybook", "mainActors" : [ "Eddie", "bear" ], "contentAbstract" : "Eddie和一只熊都在找属于自己的Teddy，Eddie找到了属于熊的，太大了。熊找到了属于Eddie的，太小了，最后他们都拿回了属于自己的Teddy,满意地抱着钻进被窝。", "isSeries" : false, "series" : { "number" : 0, "name" : "" }, "fitAgeEnd" : 6, "fileInfo" : { "isAudio" : false, "contentType" : "application/pdf", "name" : "Where is my Teddy.pdf", "suffix" : "pdf" } }, "filename" : "Where is my Teddy.pdf", "length" : 16268867, "uploadDate" : ISODate("2018-06-13T08:29:34.072Z"), "md5" : "b32f1b0c8b02a8a5e7dbb04ecaaac4cd" }
</code>【总结】
通过：
<code>db.fs.files.find().limit(10) </code>
可以输出指定个数（此处10）个结果
延伸/举一反三：
可以通过：
db.collection.find() — MongoDB Manual
知道还有其他命令：
<code>db.bios.find().limit( 5 )
db.bios.find().skip( 5 )
db.bios.find().sort( { name: 1 } )
</code>更多命令，参考官网文档。
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