Redis JSON介绍

Redis JSON

redis在6.x开始支持json
注意：json可以说是在http接口返回值的网红，之所以说是网红，是因为之前不是json，之后当然也就未可知也。
注意我上面只说了在http接口返回值的场景。实际上在内部的rpc调用，也有用json传输的，不过这比较小众。
更多使用在存储数据场景下，也是泛滥的场景，如mysql、es、mongodb、redis中，json似乎包罗万象了。
⚠️注意！这不是好事，灵活性的提升必定伴随着其他如规范性、稳定性等问题的到来，
如果还没有到来，那肯定是时间还不够长、业务还没有增长。

redis官网介绍 https://redis.io/docs/latest/develop/data-types/json/

先说说JSON是什么

JSON 指的是 JavaScript 对象表示法（JavaScript Object Notation）

再说说JSON Path

JSONPath是一种用于从JSON文档中提取信息的查询语言，类似于XML的XPath。

先推荐两个网站

JsonPath语法 https://goessner.net/articles/JsonPath/
JsonPath在线 https://jsonpath.com/

JSONPath JAVA clents

<dependency><groupId>com.jayway.jsonpath</groupId><artifactId>json-path</artifactId><version>2.7.0</version> <!-- 请检查是否有更新的版本 -->
</dependency>

Redis JSON 安装

1. 使用redis-stack
docker run -it --name redis-stack -p 6379:6379 redis/redis-stack:latest
2. 使用redis 6.x及以上，配置loadMoudle
   本文使用redis-stack，如下图，可以看到启动的时候自动加载了json模块，
   除此之外还有timeseries、search等模块

内存

官网内存 https://redis.io/docs/latest/develop/data-types/json/ram/

可以看到json的内存还是挺恐怖的，哈哈哈，用不上还是用string吧…
key和value都占用内存

json命令语法

json命令大全 https://redis.io/docs/latest/commands/?group=json

命令url

index	command	url
0	JSON.ARRAPPEND	https://redis.io/docs/latest/commands/json.arrappend/
1	JSON.ARRINDEX	https://redis.io/docs/latest/commands/json.arrindex/
2	JSON.ARRINSERT	https://redis.io/docs/latest/commands/json.arrinsert/
3	JSON.ARRLEN	https://redis.io/docs/latest/commands/json.arrlen/
4	JSON.ARRPOP	https://redis.io/docs/latest/commands/json.arrpop/
5	JSON.ARRTRIM	https://redis.io/docs/latest/commands/json.arrtrim/
6	JSON.CLEAR	https://redis.io/docs/latest/commands/json.clear/
7	JSON.DEBUG	https://redis.io/docs/latest/commands/json.debug/
8	JSON.DEBUG MEMORY	https://redis.io/docs/latest/commands/json.debug-memory/
9	JSON.DEL	https://redis.io/docs/latest/commands/json.del/
10	JSON.FORGET	https://redis.io/docs/latest/commands/json.forget/
11	JSON.GET	https://redis.io/docs/latest/commands/json.get/
12	JSON.MERGE	https://redis.io/docs/latest/commands/json.merge/
13	JSON.MGET	https://redis.io/docs/latest/commands/json.mget/
14	JSON.MSET	https://redis.io/docs/latest/commands/json.mset/
15	JSON.NUMINCRBY	https://redis.io/docs/latest/commands/json.numincrby/
16	JSON.NUMMULTBY	https://redis.io/docs/latest/commands/json.nummultby/
17	JSON.OBJKEYS	https://redis.io/docs/latest/commands/json.objkeys/
18	JSON.OBJLEN	https://redis.io/docs/latest/commands/json.objlen/
19	JSON.RESP	https://redis.io/docs/latest/commands/json.resp/
20	JSON.SET	https://redis.io/docs/latest/commands/json.set/
21	JSON.STRAPPEND	https://redis.io/docs/latest/commands/json.strappend/
22	JSON.STRLEN	https://redis.io/docs/latest/commands/json.strlen/
23	JSON.TOGGLE	https://redis.io/docs/latest/commands/json.toggle/
24	JSON.TYPE	https://redis.io/docs/latest/commands/json.type/

命令解释

JSON.ARRAPPEND

command	JSON.ARRAPPEND
syntax	JSON.ARRAPPEND key [path] value [value ...]
description	Append the json values into the array at path after the last element in it
time complexity	O(1) when path is evaluated to a single value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.arrappend/

JSON.ARRINDEX

command	JSON.ARRINDEX
syntax	JSON.ARRINDEX key path value [start [stop]]
description	Search for the first occurrence of a JSON value in an array
time complexity	O(N) when path is evaluated to a single value where N is the size of the array, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.arrindex/

JSON.ARRINSERT

command	JSON.ARRINSERT
syntax	JSON.ARRINSERT key path index value [value ...]
description	Insert the json values into the array at path before the index (shifts to the right)
time complexity	O(N) when path is evaluated to a single value where N is the size of the array, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.arrinsert/

JSON.ARRLEN

command	JSON.ARRLEN
syntax	JSON.ARRLEN key [path]
description	Report the length of the JSON array at path in key
time complexity	O(1) where path is evaluated to a single value, O(N) where path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.arrlen/

JSON.ARRPOP

command	JSON.ARRPOP
syntax	JSON.ARRPOP key [path [index]]
description	Remove and return an element from the index in the array
time complexity	O(N) when path is evaluated to a single value where N is the size of the array and the specified index is not the last element, O(1) when path is evaluated to a single value and the specified index is the last element, or O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.arrpop/

JSON.ARRTRIM

command	JSON.ARRTRIM
syntax	JSON.ARRTRIM key path start stop
description	Trim an array so that it contains only the specified inclusive range of elements
time complexity	O(N) when path is evaluated to a single value where N is the size of the array, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.arrtrim/

JSON.CLEAR

command	JSON.CLEAR
syntax	JSON.CLEAR key [path]
description	Clear container values (arrays/objects) and set numeric values to 0
time complexity	O(N) when path is evaluated to a single value where N is the size of the values, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 2.0.0
url	https://redis.io/docs/latest/commands/json.clear/

JSON.DEBUG MEMORY

command	JSON.DEBUG MEMORY
syntax	JSON.DEBUG MEMORY key [path]
description	Report a value’s memory usage in bytes
time complexity	O(N) when path is evaluated to a single value, where N is the size of the value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.debug-memory/

JSON.DEBUG

command	JSON.DEBUG
syntax	JSON.DEBUG
description	This is a container command for debugging related tasks.
time complexity	N/A
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.debug/

JSON.DEL

command	JSON.DEL
syntax	JSON.DEL key [path]
description	Delete a value
time complexity	O(N) when path is evaluated to a single value where N is the size of the deleted value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.del/

JSON.FORGET

command	JSON.FORGET
syntax	JSON.FORGET key [path]
description	See JSON.DEL.
time complexity	O(N) when path is evaluated to a single value where N is the size of the deleted value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.forget/

JSON.GET

command	JSON.GET
syntax	JSON.GET key [INDENTÂ indent] [NEWLINEÂ newline] [SPACEÂ space] [path [path ...]]
description	Return the value at path in JSON serialized form
time complexity	O(N) when path is evaluated to a single value where N is the size of the value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.get/

JSON.MERGE

command	JSON.MERGE
syntax	JSON.MERGE key path value
description	Merge a given JSON value into matching paths. Consequently, JSON values at matching paths are updated, deleted, or expanded with new children.
time complexity	O(M+N) when path is evaluated to a single value where M is the size of the original value (if it exists) and N is the size of the new value, O(M+N) when path is evaluated to multiple values where M is the size of the key and N is the size of the new value * the number of original values in the key
available in	Redis Stack / JSON 2.6.0
url	https://redis.io/docs/latest/commands/json.merge/

JSON.MGET

command	JSON.MGET
syntax	JSON.MGET key [key ...] path
description	Return the values at path from multiple key arguments
time complexity	O(M*N) when path is evaluated to a single value where M is the number of keys and N is the size of the value, O(N1+N2+…+Nm) when path is evaluated to multiple values where m is the number of keys and Ni is the size of the i-th key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.mget/

JSON.MSET

command	JSON.MSET
syntax	JSON.MSET key path value [key path value ...]
description	Set or update one or more JSON values according to the specified key-path-value triplets
time complexity	O(K*(M+N)) where k is the number of keys in the command, when path is evaluated to a single value where M is the size of the original value (if it exists) and N is the size of the new value, or O(K*(M+N)) when path is evaluated to multiple values where M is the size of the key and N is the size of the new value * the number of original values in the key
available in	Redis Stack / JSON 2.6.0
url	https://redis.io/docs/latest/commands/json.mset/

JSON.NUMINCRBY

command	JSON.NUMINCRBY
syntax	JSON.NUMINCRBY key path value
description	Increment the number value stored at path by number
time complexity	O(1) when path is evaluated to a single value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.numincrby/

JSON.OBJKEYS

command	JSON.OBJKEYS
syntax	JSON.OBJKEYS key [path]
description	Return the keys in the object that’s referenced by path
time complexity	O(N) when path is evaluated to a single value, where N is the number of keys in the object, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.objkeys/

JSON.OBJLEN

command	JSON.OBJLEN
syntax	JSON.OBJLEN key [path]
description	Report the number of keys in the JSON object at path in key
time complexity	O(1) when path is evaluated to a single value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.objlen/

JSON.SET

command	JSON.SET
syntax	JSON.SET key path value [NX | XX]
description	Set the JSON value at path in key
time complexity	O(M+N) when path is evaluated to a single value where M is the size of the original value (if it exists) and N is the size of the new value, O(M+N) when path is evaluated to multiple values where M is the size of the key and N is the size of the new value * the number of original values in the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.set/

JSON.STRAPPEND

command	JSON.STRAPPEND
syntax	JSON.STRAPPEND key [path] value
description	Append the json-string values to the string at path
time complexity	O(1) when path is evaluated to a single value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.strappend/

JSON.STRLEN

command	JSON.STRLEN
syntax	JSON.STRLEN key [path]
description	Report the length of the JSON String at path in key
time complexity	O(1) when path is evaluated to a single value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.strlen/

JSON.TOGGLE

command	JSON.TOGGLE
syntax	JSON.TOGGLE key path
description	Toggle a Boolean value stored at path
time complexity	O(1) when path is evaluated to a single value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 2.0.0
url	https://redis.io/docs/latest/commands/json.toggle/

JSON.TYPE

command	JSON.TYPE
syntax	JSON.TYPE key [path]
description	Report the type of JSON value at path
time complexity	O(1) when path is evaluated to a single value, O(N) when path is evaluated to multiple values, where N is the size of the key
available in	Redis Stack / JSON 1.0.0
url	https://redis.io/docs/latest/commands/json.type/

增

• JSON.ARRAPPEND

127.0.0.1:6379> json.set blog $ '{"user":{"id":222078,"nick":"TOM"},"id":1000,"content":"一起学习redis json吧","delete":false,"like":300,"tags":["redis","json"]}'
127.0.0.1:6379> json.arrappend blog $.tags '"backend"' '"midware"'
4
127.0.0.1:6379> json.get blog INDENT "\t" NEWLINE "\n" SPACE " " $
[{"user": {"id": 222078,"nick": "TOM"},"id": 1000,"content": "一起学习redis json吧","delete": false,"like": 300,"tags": ["redis","json","backend","midware"]}
]
127.0.0.1:6379> 

• JSON.ARRINSERT
• JSON.STRAPPEND

删

• JSON.ARRPOP
• JSON.ARRTRIM
• JSON.CLEAR
• JSON.DEL
• JSON.FORGET

改

• JSON.SET
• JSON.MSET
• JSON.NUMINCRBY
• JSON.NUMMULTBY
• JSON.MERGE
• JSON.TOGGLE

查

• JSON.ARRLEN
• JSON.ARRINDEX

  127.0.0.1:6379> JSON.SET tom $ '["black","silver"]'
  OK
  127.0.0.1:6379>
  127.0.0.1:6379>
  127.0.0.1:6379>
  127.0.0.1:6379> JSON.ARRINDEX tom $ '"black"'
  1) (integer) 0127.0.0.1:6379> JSON.ARRINDEX tom $ '"silver"'
  1) (integer) 1
  

• JSON.DEBUG
• JSON.DEBUG MEMORY
• JSON.GET
• JSON.MGET
• JSON.OBJKEYS
• JSON.OBJLEN
• JSON.RESP (deprecated)
• JSON.STRLEN
• JSON.TYPE

redis json的clients

https://github.com/RedisJSON/RedisJSON?tab=readme-ov-file

redis json的使用场景 https://redis.io/docs/latest/develop/data-types/json/use_cases/

• 从json中查询或搜索
• 原子部分更新