Redis Quick Start (2): Five common data structures of redis

1. Redis data structure

Redis stores data in the format of key and value, where keys are all strings, and value has 5 different data structures:

String type string

Hash type hash: map format

List type list: linkedlist format. Support for repeated elements

Collection type set: duplicate elements are not allowed

Sorted set type sortedset: duplicate elements are not allowed, and the elements are in order

2. String type string

2.1 Command line

Storage: set key value

127.0.0.1:6379> set username zhangsan
结果：OK

Get: get key

127.0.0.1:6379> get username
结果："zhangsan"

Delete: del key

127.0.0.1:6379> del age
结果：(integer) 1

2.2 Code

	 //1. 获取连接
	        Jedis jedis = new Jedis();//如果使用空参构造，默认值 "localhost",6379端口
	        //2. 操作
	        //存储
	        jedis.set("username","zhangsan");
	        //获取
	        String username = jedis.get("username");
	        System.out.println(username);
	
	        //可以使用setex()方法存储可以指定过期时间的 key value
	        jedis.setex("activecode",20,"hehe");//将activecode：hehe键值对存入redis，并且20秒后自动删除该键值对
	
	        //3. 关闭连接
	        jedis.close();

3. Hash type hash

3.1 Command line

Storage: hset key field value

127.0.0.1:6379> hset myhash username lisi
结果：(integer) 1

Obtain:

1)hget key field: 获取指定的field对应的值
127.0.0.1:6379> hget myhash username
结果："lisi"

2)hgetall key：获取所有的field和value
127.0.0.1:6379> hgetall myhash
结果：
				1) "username"
				2) "lisi"
				3) "password"
				4) "123"

3) Delete: hdel key field

127.0.0.1:6379> hdel myhash username
结果：(integer) 1

3.2 Code

//1. 获取连接
	        Jedis jedis = new Jedis();//如果使用空参构造，默认值 "localhost",6379端口
	        //2. 操作
	        // 存储hash
	        jedis.hset("user","name","lisi");
	        jedis.hset("user","age","23");
	        jedis.hset("user","gender","female");
	
	        // 获取hash
	        String name = jedis.hget("user", "name");
	        System.out.println(name);

			// 获取hash的所有map中的数据
			Map<String, String> user = jedis.hgetAll("user");
 			 // keyset
	        Set<String> keySet = user.keySet();
	        for (String key : keySet) {
    
    
	            //获取value
	            String value = user.get(key);
	            System.out.println(key + ":" + value);
	        }
	
	        //3. 关闭连接
	        jedis.close();

4. List type list

4.1 Command line

list: You can add an element to the head (left) or tail (right) of the list.

1) Add:

1. lpush key value: 将元素加入列表左表
2. rpush key value：将元素加入列表右边

127.0.0.1:6379> lpush myList a
(integer) 1

127.0.0.1:6379> lpush myList b
(integer) 2

127.0.0.1:6379> rpush myList c
(integer) 3

2) Get

* lrange key start end ：范围获取
127.0.0.1:6379> lrange myList 0 -1
1) "b"
2) "a"
3) "c"

3) Delete:

* lpop key： 删除列表最左边的元素，并将元素返回
* rpop key： 删除列表最右边的元素，并将元素返回

4.2 Code

List type list: linkedlist format. Support repeating elements
lpush / rpush
lpop / rpop
lrange start end: range acquisition

			
			 //1. 获取连接
	        Jedis jedis = new Jedis();//如果使用空参构造，默认值 "localhost",6379端口
	        //2. 操作
	        // list 存储
	        jedis.lpush("mylist","a","b","c");//从左边存
	        jedis.rpush("mylist","a","b","c");//从右边存
	
	        // list 范围获取
	        List<String> mylist = jedis.lrange("mylist", 0, -1);
	        System.out.println(mylist);
	        
	        // list 弹出
	        String element1 = jedis.lpop("mylist");//c
	        System.out.println(element1);
	
	        String element2 = jedis.rpop("mylist");//c
	        System.out.println(element2);
	
	        // list 范围获取
	        List<String> mylist2 = jedis.lrange("mylist", 0, -1);
	        System.out.println(mylist2);
	
	        //3. 关闭连接
	        jedis.close();

5. Collection type set

5.1 Command line

Collection type set: Repeated elements are not allowed.

1) Storage: sadd key value

127.0.0.1:6379> sadd myset a
(integer) 1
127.0.0.1:6379> sadd myset a
(integer) 0

2) Get: smembers key: get all elements in the set collection

127.0.0.1:6379> smembers myset
1) "a"

3) Delete: srem key value: delete an element in the set collection

127.0.0.1:6379> srem myset a
(integer) 1

5.2 Code

Collection types set: do not allow duplicate elements
Sadd:
smembers: Get all the elements

			//1. 获取连接
	        Jedis jedis = new Jedis();//如果使用空参构造，默认值 "localhost",6379端口
	        //2. 操作
			// set 存储 
jedis.sadd("myset","java","php","c++");

			// set 获取
	        Set<String> myset = jedis.smembers("myset");
	        System.out.println(myset);
	
	        //3. 关闭连接
	        jedis.close();

6. Sorted set type sortedset (zset)

6.1 Command line

Ordered set type sortedset: duplicate elements are not allowed, and the elements are in order. Each element will be associated with a double type score. Redis uses scores to sort the members of the collection from small to large.

1) Storage: zadd key score value

127.0.0.1:6379> zadd mysort 60 zhangsan
(integer) 1
127.0.0.1:6379> zadd mysort 50 lisi
(integer) 1
127.0.0.1:6379> zadd mysort 80 wangwu
(integer) 1

2）获取：zrange key start end [withscores]

127.0.0.1:6379> zrange mysort 0 -1
1) "lisi"
2) "zhangsan"
3) "wangwu"

127.0.0.1:6379> zrange mysort 0 -1 withscores
1) "zhangsan"
2) "60"
3) "wangwu"
4) "80"
5) "lisi"
6) "500"

3) Delete: zrem key value

127.0.0.1:6379> zrem mysort lisi
(integer) 1

6.2 Code

Sorted set type sortedset: repeating elements are not allowed, and the elements are ordered.
zadd
zrange

			//1. 获取连接
	        Jedis jedis = new Jedis();//如果使用空参构造，默认值 "localhost",6379端口
	        //2. 操作
	        // sortedset 存储
	        jedis.zadd("mysortedset",3,"亚瑟");
	        jedis.zadd("mysortedset",30,"后裔");
	        jedis.zadd("mysortedset",55,"孙悟空");
	
	        // sortedset 获取
	        Set<String> mysortedset = jedis.zrange("mysortedset", 0, -1);
	
	        System.out.println(mysortedset);

7, general order

keys *: Query all keys

type key: Get the type of value corresponding to the key

del key: delete the specified key value

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