JavaWeb [Redis] data types and instructions

Redis data type

(1) Redis and Map analogy
Redis stores data in the form of keys and values. Redis can be understood as a Map collection
1: Key: all strings
2: Value: There are five data types: string json string
string (String)! !! Key----value Map<String,String>
hash (hash) Big key—small key—value Map<String,Map<String,String>>
list of strings (list) key----value 1 , Value 2, value 3 Map<String,LinkedList>
string set (set) key----value 1, value 2, value 3 Map<String, HashSet>
sorted set key--- -Value 1, Value 2, Value 3 Map<String,LinkedHashSet>
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(2) What is enough to master the value of the string type?
The other four collections can be converted into json strings, no need to master

Redis instruction-string type***

(1) String type string
(2) Instructions

 set name baoqiang  //添加一个键值对  如果键存在，则修改  set()
 get name           //根据键获取值
 del name           //根据键删除键值对
 mget name age      //根据多个键查看值
1234

Redis instruction-Hash type

(1) Hash (hash)

  hset myhash username haohao  //添加数据
  hset 北京    111     冰冰
  hget myhash username         //根据大键和小键获取值
  hdel myhash username         //根据大键和小键删除值
1234

Redis instruction-list type List

(1)
The value of list type list can be repeated.
Stack: first in, last out
(2) Instructions

lpush mylist a b c  //压栈 添加数据，键为mylist 值为：a b  c
lpop  mylist        //从左边弹栈  删除操作，删除的顺序和添加的顺序相反
rpop  mylist        //从右边弹栈
123

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Redis instruction-set type set

(1)
The value of the collection type set cannot be repeated

  sadd myset a b c  //添加数据
  smembers myset    //获取数据
  srem myset a b    //删除数据
123

Redis instructions-general instructions

(1) Redis general instructions

Commands that can be used for all data types

  keys *      //查看Redis中所有的键  
  del  myset  //删除指定的键值对
  exists key  //判断键是否存在   0表示不存在，  1表示存在
  type myset  //测试你的键是什么类型