Redis

是NoSQL的
官网

Redis:
	1.NoSQL的数据库
	2.key-value方式存储的  内存数据库
	    key ：通常是String类型
	    value：strings, hashes, lists, sets, sorted sets  等 选择哪一个根据业务来定的 
redis 数据存在内存里的 万一挂掉了怎么办？
虽然内部有机制  ： 定时的把内存数据 刷到磁盘上面 重启之后 可以把磁盘上的数据加载进来的



特性：
	1.速度快 1s 十万次  读写非常好的 
	2. 持久化   两种 RBD(快照的方式 ) 和 AOF(记录所有操作的 写到日志文件里去的)的  
	    重启之后优先AOF  因为 数据更加完整  RBD是定时的快照 
	    	eg：10s 做一次快照 8s的时候挂掉了  这8s的数据就丢了 
	3.数据类型 
	4.多语言的  java scala 都可以
	5.其他功能 ： 发布订阅 事务 pipeline(指的是 多条指令 可以放在一起 最后 发一条指令    代替 而不是一条数据一个指令  网络传输少很多  工作当中批量的 一定要采用pipeline的方式 发送请求)
	6.单线程的 
	7.有集群 有主从复制    来保证分布式和高可用

国内 微博 使用redis的多

操作：

[double_happy@hadoop101 src]$ ls redis-server 
redis-server                服务端的 
[double_happy@hadoop101 src]$ ls redis-cli
redis-cli                         客户端的
[double_happy@hadoop101 src]$


[double_happy@hadoop101 redis-5.0.5]$ make  install
cd src && make install
make[1]: Entering directory `/home/double_happy/app/redis-5.0.5/src'
    CC Makefile.dep
make[1]: Leaving directory `/home/double_happy/app/redis-5.0.5/src'
make[1]: Entering directory `/home/double_happy/app/redis-5.0.5/src'

Hint: It's a good idea to run 'make test' ;)

    INSTALL install
install: cannot create regular file ‘/usr/local/bin/redis-server’: Permission denied
make[1]: *** [install] Error 1
make[1]: Leaving directory `/home/double_happy/app/redis-5.0.5/src'
make: *** [install] Error 2
[double_happy@hadoop101 redis-5.0.5]$ sudo make install
cd src && make install
make[1]: Entering directory `/home/double_happy/app/redis-5.0.5/src'

Hint: It's a good idea to run 'make test' ;)

    INSTALL install
    INSTALL install
    INSTALL install
    INSTALL install
    INSTALL install
make[1]: Leaving directory `/home/double_happy/app/redis-5.0.5/src'


注意：
你把redis编译好了 
‘/usr/local/bin/redis-server 这个目录下也是有 redis-server的

启动：
[double_happy@hadoop101 ~]$ redis-server 
27132:C 29 Oct 2019 13:41:11.883 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
27132:C 29 Oct 2019 13:41:11.883 # Redis version=5.0.5, bits=64, commit=00000000, modified=0, pid=27132, just started
27132:C 29 Oct 2019 13:41:11.883 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
                _._                                                  
           _.-``__ ''-._                                             
      _.-``    `.  `_.  ''-._           Redis 5.0.5 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._                                   
 (    '      ,       .-`  | `,    )     Running in standalone mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 6379
 |    `-._   `._    /     _.-'    |     PID: 27132
  `-._    `-._  `-./  _.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |           http://redis.io        
  `-._    `-._`-.__.-'_.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |                                  
  `-._    `-._`-.__.-'_.-'    _.-'                                   
      `-._    `-.__.-'    _.-'                                       
          `-._        _.-'                                           
              `-.__.-'                                               

27132:M 29 Oct 2019 13:41:11.884 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
27132:M 29 Oct 2019 13:41:11.884 # Server initialized
27132:M 29 Oct 2019 13:41:11.884 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
27132:M 29 Oct 2019 13:41:11.884 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
27132:M 29 Oct 2019 13:41:11.884 * Ready to accept connections


注意：
6379  redis经典端口  

[double_happy@hadoop101 redis-5.0.5]$ ps -ef | grep redis
double_+ 27132 16513  0 13:41 pts/1    00:00:00 redis-server *:6379
double_+ 27148 15274  0 13:42 pts/0    00:00:00 grep --color=auto redis
[double_happy@hadoop101 redis-5.0.5]$ 

说明redis  服务端启动了 
再启动客户端 ：


[double_happy@hadoop101 ~]$ redis-cli 
127.0.0.1:6379> keys*
(error) ERR unknown command `keys*`, with args beginning with: 
127.0.0.1:6379> keys *
(empty list or set)
127.0.0.1:6379> set name double_happy
OK
127.0.0.1:6379> keys *
1) "name"
127.0.0.1:6379> get name
"double_happy"
127.0.0.1:6379>

后台运行：需要对redis.conf 文件进行简单的配置 配置一下 logfile位置 

[double_happy@hadoop101 redis-5.0.5]$ src/redis-server redis.conf              
[double_happy@hadoop101 redis-5.0.5]$ tail -200f ~/tmp/redislogs/redis.log 
27337:C 29 Oct 2019 13:53:20.629 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
27337:C 29 Oct 2019 13:53:20.629 # Redis version=5.0.5, bits=64, commit=00000000, modified=0, pid=27337, just started
27337:C 29 Oct 2019 13:53:20.629 # Configuration loaded
                _._                                                  
           _.-``__ ''-._                                             
      _.-``    `.  `_.  ''-._           Redis 5.0.5 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._                                   
 (    '      ,       .-`  | `,    )     Running in standalone mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 6379
 |    `-._   `._    /     _.-'    |     PID: 27338
  `-._    `-._  `-./  _.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |           http://redis.io        
  `-._    `-._`-.__.-'_.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |                                  
  `-._    `-._`-.__.-'_.-'    _.-'                                   
      `-._    `-.__.-'    _.-'                                       
          `-._        _.-'                                           
              `-.__.-'                                               

27338:M 29 Oct 2019 13:53:20.632 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
27338:M 29 Oct 2019 13:53:20.632 # Server initialized
27338:M 29 Oct 2019 13:53:20.632 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
27338:M 29 Oct 2019 13:53:20.632 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
27338:M 29 Oct 2019 13:53:20.632 * Ready to accept connections
^C
[double_happy@hadoop101 redis-5.0.5]$ ^C

客户端操作：  需要把redis.conf  里的 bind 去掉 或者 配置成 0.0.0.0
[double_happy@hadoop101 redis-5.0.5]$ src/redis-cli -h hadoop101 -p 6379
hadoop101:6379> 

再黑窗口查看 redis还是比较麻烦的 
https://www.jianshu.com/p/6895384d2b9e 安装一下

在这里插入图片描述

Redis多数据库特性：
	1.默认有16个数据库   可以改的   redis.conf       
		通常情况下 数据库之间是 隔离的
	2.

在这里插入图片描述

Redis 切换库 黑窗口：

hadoop101:6379> select 1
OK
hadoop101:6379[1]> select 0
OK
hadoop101:6379> select 16
(error) ERR DB index is out of range
hadoop101:6379>

在这里插入图片描述

1.	通常情况下 数据库之间是 隔离的

hadoop101:6379> select 1
OK
hadoop101:6379[1]> set  bigdata spark
OK
hadoop101:6379[1]> get  bigdata
"spark"
hadoop101:6379[1]> select 0
OK
hadoop101:6379> get bigdata
(nil)
hadoop101:6379> 

注意:
flushall   这个操作没有做隔离的 会把所有的库里的东西 全部干掉 


hadoop101:6379> FLUSHALL
OK
hadoop101:6379> select 1
OK
hadoop101:6379[1]> get bigdata
(nil)
hadoop101:6379[1]>

redis里的基础命令：
	1. keys  *    查你当前库里的所有的key
	   这个keys 是能进行匹配的 
eg：
hadoop101:6379> set name 1
OK
hadoop101:6379> set name2 xx
OK
hadoop101:6379> set name3 ll
OK
hadoop101:6379> keys *
1) "name3"
2) "name2"
3) "name"
hadoop101:6379> keys name*
1) "name3"
2) "name2"
3) "name"
hadoop101:6379> keys name?
1) "name3"
2) "name2"
hadoop101:6379> keys name[0-9]
1) "name3"
2) "name2"
hadoop101:6379>

2.判断某一个key 存不存在 
exists  对应的key      返回1 表示存在 
eg：
hadoop101:6379> EXISTS name
(integer) 1
hadoop101:6379> EXISTS name10
(integer) 0
hadoop101:6379>

3.删除  
del  key 
del key1 key2

hadoop101:6379> DEL name 
(integer) 1
hadoop101:6379> del name1 name2
(integer) 1
hadoop101:6379> 

或者 会到外面删除 
[double_happy@hadoop101 redis-5.0.5]$ src/redis-cli keys "*"
1) "name1"
2) "name3"
3) "name2"
[double_happy@hadoop101 redis-5.0.5]$ src/redis-cli del `redis-cli keys "name*"`
(integer) 3
[double_happy@hadoop101 redis-5.0.5]$ src/redis-cli keys "*"
(empty list or set)
[double_happy@hadoop101 redis-5.0.5]$

命令太多了看官网
Commands

查看 key的类型：
hadoop101:6379> type name
string

但是真的记不住怎么办？
help

hadoop101:6379> help
redis-cli 5.0.5
To get help about Redis commands type:
      "help @<group>" to get a list of commands in <group>
      "help <command>" for help on <command>
      "help <tab>" to get a list of possible help topics
      "quit" to exit

To set redis-cli preferences:
      ":set hints" enable online hints
      ":set nohints" disable online hints
Set your preferences in ~/.redisclirc


注意：
help  @<group>  用的最多

eg：
hadoop101:6379> help @string

  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

  BITFIELD key [GET type offset] [SET type offset value] [INCRBY type offset increment] [OVERFLOW WRAP|SAT|FAIL]
  summary: Perform arbitrary bitfield integer operations on strings
  since: 3.2.0

  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 [expiration 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

hadoop101:6379>

数据类型：
这个需要掌握的

String类型：
setnx ：
SETNX key value
  summary: Set the value of a key, only if the key does not exist
  since: 1.0.0

很多 incr可以用来统计在线人数

Hash类型： ***
场景 多了一个字段  假如 100行数据只有一条记录  多了这个字段
大数据里 偏移量使用它 来存储的 

hmset:
对已有的会修改 对没有的会加上去

在这里插入图片描述

idea开发

public class RedisApp {

    String host = "hadoop101";
    int port = 6379;

    Jedis jedis ;


    @Test
    public void test01() {
        jedis.set("info", "double_happy");

        Assert.assertEquals("double_happy",jedis.get("info"));
    }



    @Before
    public void setUp() {
        jedis = new Jedis(host,port);
    }


    public void tearDown() {
        jedis.close();
    }
}
查看结果： 绿了哈    注意命令和api 一一对应的 

突然想到一个梗 ：
	异地恋最重要的是什么？
	最重要的是 相互信任  这样对四个人都好

在这里插入图片描述