二：redis的hash类型相关操作
=====================二种：hash类型================== 介绍：redis - hash是一个string类型的field和value的映射表 hash特别适合对应存储对象，相较于将对象的每个字段存成单个string类型 将一个对象存储在hash类型中会占用更少的内存，并且可以方便的存取
=====================二种：hash类型==================介绍：redis -> hash是一个string类型的field和value的映射表
hash特别适合对应存储对象，相较于将对象的每个字段存成单个string类型
将一个对象存储在hash类型中会占用更少的内存，并且可以方便的存取整个对象
0：hset *如果 key（就是hash表） 不存在，一个新的哈希表被创建并进行 HSET 操作
设置hash field为指定值，如果key不存在，则先创建
例子：hset user:001 name leyangjun 会创建表
0.2：hsetnx
设置hash field 为指定值，如果不存在，则创建，如果存在则返回0
例子：hsetnx user:002 name leyangjun
1：hmset：设置多个哈希表的字段值
同时设置hash的多个field
例子：hmset user003 name leyangjun age 23 sex 1 -->对哈希表003设置值成功
hget获取: hget user:003 name -->获取哈希表003 name的值
2：hget
获取指定的hash field值
例子：hget user003 name -->表明 字段
3: hmget
获取全部指定的hash field
例子：hmget user:003 name age sex
4：hincrby （对某个值就行自）
指定的hash field加上给定值
例子：hincrby user:003 age 5 -->给原来age的值 加 5 20+5
5: hexists
测试指定的field是否存在
例子: hexists user:003 sex -->判断hash表字段是否存在
6：hlen
返回指定hash表中所有的field数
例子：hlen user003
7：hdel
删除指定hash表中field的值
例子：hdel user003 age -->删除user003 表中age的字段
8：hkeys
返回hash表中所有的字段
例子：hkeys user003
9：hvals
返回hash表的所有value
例子：hvals user003 -->所有表中key对应的值
10：* hgetall 常用
获取某个hash中全部的field及value
例子：hgetall user003
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