Redis之数据类型Sting字符串

Redis

String（字符串）

string是redis最基本的类型，你可以理解成与Memcached一模一样的类型，一个key对应一个value。

string类型是二进制安全的。意思是redis的string可以包含任何数据。比如jpg图片或者序列化的对象 。

string类型是Redis最基本的数据类型，一个键最大能存储512MB。

应用场景：

String是最常用的一种数据类型，普通的key/ value 存储都可以归为此类.即可以完全实现目前 Memcached 的功能，并且效率更高。还可以享受Redis的定时持久化，操作日志及 Replication等功能。除了提供与 Memcached 一样的get、set、incr、decr 等操作外，Redis还提供了下面一些操作：

• 获取字符串长度
• 往字符串append内容
• 设置和获取字符串的某一段内容
• 设置及获取字符串的某一位（bit）
• 批量设置一系列字符串的内容

command

• APPEND key value

  • summary: Append a value to a key
  • since: 2.0.0

• BITCOUNT key [start] [end]

  • summary: Count set bits in a string
  • since: 2.6.0

• BITOP operation destkey key [key ...]

  • summary: Perform bitwise operations between strings
  • since: 2.6.0

• BITPOS key bit [start] [end]

  • summary: Find first bit set or clear in a string
  • since: 2.8.7

• DECR key

  • summary: Decrement the integer value of a key by one
  • since: 1.0.0

• DECRBY key decrement

  • summary: Decrement the integer value of a key by the given number
  • since: 1.0.0

• GET key

  • summary: Get the value of a key
  • since: 1.0.0

• GETBIT key offset

  • summary: Returns the bit value at offset in the string value stored at key
  • since: 2.2.0

• GETRANGE key start end

  • summary: Get a substring of the string stored at a key
  • since: 2.4.0

• GETSET key value

  • summary: Set the string value of a key and return its old value
  • since: 1.0.0

• INCR key

  • summary: Increment the integer value of a key by one
  • since: 1.0.0

• INCRBY key increment

  • summary: Increment the integer value of a key by the given amount
  • since: 1.0.0

• INCRBYFLOAT key increment

  • summary: Increment the float value of a key by the given amount
  • since: 2.6.0

• MGET key [key ...]

  • summary: Get the values of all the given keys
  • since: 1.0.0

• MSET key value [key value ...]

  • summary: Set multiple keys to multiple values
  • since: 1.0.1

• MSETNX key value [key value ...]

  • summary: Set multiple keys to multiple values, only if none of the keys exist
  • since: 1.0.1

• PSETEX key milliseconds value

  • summary: Set the value and expiration in milliseconds of a key
  • since: 2.6.0

• SET key value [EX seconds] [PX milliseconds] [NX|XX]

  • summary: Set the string value of a key
  • since: 1.0.0

• SETBIT key offset value

  • summary: Sets or clears the bit at offset in the string value stored at key
  • since: 2.2.0

• SETEX key seconds value

  • summary: Set the value and expiration of a key
  • since: 2.0.0

• SETNX key value

  • summary: Set the value of a key, only if the key does not exist
  • since: 1.0.0

• SETRANGE key offset value

  • summary: Overwrite part of a string at key starting at the specified offset
  • since: 2.2.0

• STRLEN key

  • summary: Get the length of the value stored in a key
  • since: 2.2.0