redis之List数据类型以及存储原理

文章目录

• ​​1.概述​​

• ​​1.1.特点​​

• ​​1.1.1.有顺序​​
• ​​1.1.2.可以重复​​

• ​​2.相关命令​​

• ​​2.1.将一个或多个值 value 从左边插入到列表 key 的表头:​​

• ​​2.1.1.不管key是否存在，都插入：lpush teacher_name_list tom frank jerry jim lucy lily​​
• ​​2.1.2.只有key存在时，才插入:lpushx parent liubei​​

• ​​2.2.返回列表 key 中指定区间内的所有元素:LRANGE teacher_name_list 0 -1​​
• ​​2.3.将一个或多个值 value 从右边插入到列表 key 的表头:​​

• ​​2.3.1.不管key是否存在，都插入:RPUSH teacher_name_list gaoxinfu zhaobolun​​
• ​​2.3.2.只有当key存在时候，才插入:rpushx parent gaoxinfu​​

• ​​2.4.从左边移除第一个元素:lpop teacher_name_list​​
• ​​2.5.从右边移除第一个元素:rpop teacher_name_list​​
• ​​2.6.返回指定list下标的value:lindex teacher_name_list 1​​
• ​​2.7.返回list数组的长度:LLEN teacher_name_list​​
• ​​2.8.移除list数组中的元素:​​

• ​​2.8.1. 删除从最后面数，1个值为jim的值:lrem teacher_name_list -1 jim​​
• ​​2.8.2. 删除从最后面数，2个值为jim的值，实际上因为只有一个jim，所以返回删除个数为1:lrem teacher_name_list -2 jim​​
• ​​2.8.3. 删除从最后面数，2个值为frank的值:lrem teacher_name_list -2 frank​​
• ​​2.8.4. 删除从最前面数，1个值为lucy的值:lrem teacher_name_list 1 lucy​​

• ​​2.9.向list数组插入value值​​

• ​​2.9.1.在list数组中某个值之前插入值：linsert teacher_name_list before tom lucy​​
• ​​2.9.2.在list数组中某个值之后插入值：linsert teacher_name_list after tom lily​​

• ​​2.10.将children数组中的最后一个元素放到parent数组的第一个元素:RPOPLPUSH children parent​​
• ​​2.11.blpop的使用：http://redisdoc.com/list/blpop.html​​
• ​​2.12.brpop的使用：http://redisdoc.com/list/brpop.html​​
• ​​2.13.查看存储类型：object encoding parent​​

• ​​3.List列表存储原理​​

• ​​3.1.quicklist​​

• ​​4.应用场景​​

• ​​4.1.时间线​​
• ​​4.2.消息队列​​
• ​​4.3.JVM虚拟机中的栈​​

1.概述

1.存储有序的字符串（从左到右），元素可以重复。可以充当队列和栈的角色。

1.1.特点

1.1.1.有顺序

1.1.2.可以重复

2.相关命令

2.1.将一个或多个值 value 从左边插入到列表 key 的表头:

2.1.1.不管key是否存在，都插入：lpush teacher_name_list tom frank jerry jim lucy lily

127.0.0.1:6379> lpush  teacher_name_list tom frank jerry jim lucy lily
(integer) 6
127.0.0.1:6379> LRANGE teacher_name_list 0 -1
1) "lily"
2) "lucy"
3) "jim"
4) "jerry"
5) "frank"
6) "tom"
127.0.0.1:6379>

注意下

lpush  teacher_name_list tom frank jerry jim lucy lily
等价于
lpush  teacher_name_list tom；
lpush  teacher_name_list frank；
lpush  teacher_name_list jerry；
lpush  teacher_name_list jim；
lpush  teacher_name_list lucy；
lpush  teacher_name_list lily；

2.1.2.只有key存在时，才插入:lpushx parent liubei

由于key：teachers不存在，所以插入失败

127.0.0.1:6379> lrange teachers 0 -1
(empty list or set)
127.0.0.1:6379> lpushx teachers gaoxinfu
(integer) 0
127.0.0.1:6379>

key：parent存在，所以插入成功

127.0.0.1:6379> lrange parent 0 -1
1) "tom"
2) "liran"
3) "gaoxinfu"
127.0.0.1:6379> lpushx parent liubei
(integer) 4
127.0.0.1:6379> 
127.0.0.1:6379> lrange parent 0 -1
1) "liubei"
2) "tom"
3) "liran"
4) "gaoxinfu"
127.0.0.1:6379>

2.2.返回列表 key 中指定区间内的所有元素:LRANGE teacher_name_list 0 -1

0是第一个，-1是最后一个，1是第一个，-2是倒数第二个

127.0.0.1:6379> LRANGE teacher_name_list 0 -1
1) "lily"
2) "lucy"
3) "jim"
4) "jerry"
5) "frank"
6) "tom"
127.0.0.1:6379>

2.3.将一个或多个值 value 从右边插入到列表 key 的表头:

2.3.1.不管key是否存在，都插入:RPUSH teacher_name_list gaoxinfu zhaobolun

从最后面开始插入数据

127.0.0.1:6379> RPUSH teacher_name_list gaoxinfu zhaobolun
(integer) 8
127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "lily"
2) "lucy"
3) "jim"
4) "jerry"
5) "frank"
6) "tom"
7) "gaoxinfu"
8) "zhaobolun"
127.0.0.1:6379>

2.3.2.只有当key存在时候，才插入:rpushx parent gaoxinfu

由于key：teachers不存在，所以插入失败

127.0.0.1:6379> rpushx teachers gaoxinfu
(integer) 0
127.0.0.1:6379> lrange teachers 0 -1
(empty list or set)
127.0.0.1:6379> rpushx teachers gaoxinfu
(integer) 0
127.0.0.1:6379>

key:parent 存在，所以插入成功

127.0.0.1:6379> rpushx parent gaoxinfu
(integer) 5
127.0.0.1:6379> lrange parent 0 -1
1) "liubei"
2) "tom"
3) "liran"
4) "gaoxinfu"
5) "gaoxinfu"
127.0.0.1:6379>

2.4.从左边移除第一个元素:lpop teacher_name_list

127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "lily"
2) "lucy"
3) "jim"
4) "jerry"
5) "frank"
6) "tom"
7) "gaoxinfu"
8) "zhaobolun"
127.0.0.1:6379> lpop teacher_name_list
"lily"
127.0.0.1:6379>

再次查询结果如下,lily被移除

127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "lucy"
2) "jim"
3) "jerry"
4) "frank"
5) "tom"
6) "gaoxinfu"
7) "zhaobolun"
127.0.0.1:6379>

2.5.从右边移除第一个元素:rpop teacher_name_list

127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "lucy"
2) "jim"
3) "jerry"
4) "frank"
5) "tom"
6) "gaoxinfu"
7) "zhaobolun"
127.0.0.1:6379> rpop teacher_name_list
"zhaobolun"

再次查询，发现zhaobolun已经被移除

127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "lucy"
2) "jim"
3) "jerry"
4) "frank"
5) "tom"
6) "gaoxinfu"
127.0.0.1:6379>

2.6.返回指定list下标的value:lindex teacher_name_list 1

第一个下标是0，第二个下标示1

127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "lucy"
2) "jim"
3) "jerry"
4) "frank"
5) "tom"
6) "gaoxinfu"
127.0.0.1:6379> lindex teacher_name_list 1
"jim"
127.0.0.1:6379> lindex teacher_name_list -1
"gaoxinfu"
127.0.0.1:6379> lindex teacher_name_list -3
"frank"
127.0.0.1:6379>

如果要返回连续的多个，使用lrange

2.7.返回list数组的长度:LLEN teacher_name_list

127.0.0.1:6379> LRANGE teacher_name_list 0 -1
1) "lucy"
2) "jim"
3) "jerry"
4) "frank"
5) "tom"
6) "gaoxinfu"
127.0.0.1:6379> LLEN teacher_name_list
(integer) 6
127.0.0.1:6379>

2.8.移除list数组中的元素:

格式

LREM key count value;

说明

根据参数 count 的值，移除列表中与参数 value 相等的元素。
count 的值可以是以下几种：
count > 0 : 从表头开始向表尾搜索，移除与 value 相等的元素，数量为 count 。
count < 0 : 从表尾开始向表头搜索，移除与 value 相等的元素，数量为 count 的绝对值。
count = 0 : 移除表中所有与 value 相等的值。
返回值
被移除元素的数量。 因为不存在的 key 被视作空表(empty list)，所以当 key 不存在时， LREM 命令总是返回 0

127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "frank"
2) "lucy"
3) "jim"
4) "jerry"
5) "frank"
6) "tom"
7) "gaoxinfu"
8) "jim"

2.8.1. 删除从最后面数，1个值为jim的值:lrem teacher_name_list -1 jim

127.0.0.1:6379> lrem teacher_name_list -1 jim
(integer) 1

2.8.2. 删除从最后面数，2个值为jim的值，实际上因为只有一个jim，所以返回删除个数为1:lrem teacher_name_list -2 jim

127.0.0.1:6379> lrem teacher_name_list -2 jim
(integer) 1
127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "frank"
2) "lucy"
3) "jerry"
4) "frank"
5) "tom"
6) "gaoxinfu"

2.8.3. 删除从最后面数，2个值为frank的值:lrem teacher_name_list -2 frank

127.0.0.1:6379> lrem teacher_name_list -2 frank
(integer) 2
127.0.0.1:6379> 
127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "lucy"
2) "jerry"
3) "tom"
4) "gaoxinfu"

2.8.4. 删除从最前面数，1个值为lucy的值:lrem teacher_name_list 1 lucy

127.0.0.1:6379> lrem teacher_name_list 1 lucy
(integer) 1
127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "jerry"
2) "tom"
3) "gaoxinfu"
127.0.0.1:6379>

2.9.向list数组插入value值

2.9.1.在list数组中某个值之前插入值：linsert teacher_name_list before tom lucy

127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "jerry"
2) "tom"
3) "gaoxinfu"
127.0.0.1:6379> linsert teacher_name_list before tom lucy
(integer) 4
127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "jerry"
2) "lucy"
3) "tom"
4) "gaoxinfu"
127.0.0.1:6379>

2.9.2.在list数组中某个值之后插入值：linsert teacher_name_list after tom lily

127.0.0.1:6379> lrange teacher_name_list 0 -1
1) "jerry"
2) "lucy"
3) "tom"
4) "gaoxinfu"
127.0.0.1:6379> linsert teacher_name_list after tom lily
(integer) 5
127.0.0.1:6379>

2.10.将children数组中的最后一个元素放到parent数组的第一个元素:RPOPLPUSH children parent

(integer) 2
127.0.0.1:6379> lrange children 0 -1
1) "lily"
2) "lucy"
3) "tom"
127.0.0.1:6379> lrange parent 0 -1
1) "liran"
2) "gaoxinfu"
127.0.0.1:6379> 
127.0.0.1:6379> RPOPLPUSH children parent
"tom"
127.0.0.1:6379> lrange children 0 -1
1) "lily"
2) "lucy"
127.0.0.1:6379> lrange parent 0 -1
1) "tom"
2) "liran"
3) "gaoxinfu"
127.0.0.1:6379>

2.11.blpop的使用：http://redisdoc.com/list/blpop.html

2.12.brpop的使用：http://redisdoc.com/list/brpop.html

2.13.查看存储类型：object encoding parent

127.0.0.1:6379> object encoding parent
"quicklist"
127.0.0.1:6379>

3.List列表存储原理

quicklist（快速列表）是ziplist 和linkedlist 的结合体。
quicklist.h，head 和tail 指向双向列表的表头和表尾

3.1.quicklist

typedef struct quicklist {
    quicklistNode *head;
    quicklistNode *tail;
    unsigned long count;        /* total count of all entries in all ziplists */
    unsigned long len;          /* number of quicklistNodes */
    int fill : QL_FILL_BITS;              /* fill factor for individual nodes */
    unsigned int compress : QL_COMP_BITS; /* depth of end nodes not to compress;0=off */
    unsigned int bookmark_count: QL_BM_BITS;
    quicklistBookmark bookmarks[];
} quicklist;

4.应用场景

4.1.时间线

1.用户浏览记录的时间线
2.网页浏览

4.2.消息队列

1.我们在存储消息的时候，lpush 压入队列
2.我们消费消息的时候，rpop 先入先出的消费消息内容

4.3.JVM虚拟机中的栈

1.压栈的处理：是先进后出，rpush，brpop