redis通用指令、Jedis

蔚落 2023-01-07 07:20 111阅读 0赞

删除指定key

del key

获取key是否存在

exists key

获取key的类型

type key

为指定key设置有效期

expire key seconds
    pexpire key milliseconds
    expireat key timestamp
    pexpireat key milliseconds-timestamp

获取key的有效时间

ttl key
    pttl key

切换key从时效性转换为永久性

persist key

查询key

keys pattern

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为key改名

rename key newkey
    renamenx key newkey

对所有key排序

sort

其他key通用操作

help @generic

**数据库通用操作**  
key 的重复问题  
key是由程序员定义的。redis在使用过程中，伴随着操作数据量的增加，会出现大量的数据以及对应的key。数据不区分种类、类别混杂在一起，极易出现重复或冲突

redis为每个服务提供有16个数据库，编号从0到15，每个数据库之间的数据相互独立。

**db 基本操作**  
切换数据库

select index

其他操作

quit
    ping
    echo message

数据移动

move key db

数据清除

dbsize
    flushdb
    flushall

## Jedis ##

**jar包导入**  
下载地址：https://mvnrepository.com/artifact/redis.clients/jedis

**基于maven 引入依赖**

<dependency>
     <groupId>redis.clients</groupId>
     <artifactId>jedis</artifactId>
     <version>2.9.0</version>
    </dependency>

public class JedisTest {
        
    
        @Test
        public void testJedis(){
        
            //1.连接redis
            Jedis jedis = new Jedis("127.0.0.1", 6379);
    
            //2.操作redis
            jedis.set("name","xxp");
            String name = jedis.get("name");
            System.out.println(name);
            //3.关闭redis
            jedis.close();
    
        }
        @Test
        public void testList(){
        
            Jedis jedis = new Jedis("127.0.0.1", 6379);
            jedis.lpush("list2","a","b","c");
            jedis.rpush("list2","d","e","f");
            List<String> res = jedis.lrange("list2", 0, -1);
            System.out.println("list2"+jedis.llen("list2"));
            for (String tem:res){
        
                System.out.println(tem);
            }
            jedis.close();
        }
    
        @Test
        public void testHash(){
        
            Jedis jedis = new Jedis("127.0.0.1", 6379);
            jedis.hset("name","Sharpen","100");
            jedis.hset("name","Giana","101");
            Map<String, String> name = jedis.hgetAll("name");
            for (Map.Entry<String,String> entry:name.entrySet()){
        
                System.out.println(entry.getKey()+":"+entry.getValue());
            }
            System.out.println("lens:"+jedis.hlen("name"));
            jedis.close();
        }
    }

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public class Service {
        
        String id;
        int num;
        public Service(String id,int num) {
        
            this.id=id;
            this.num=num;
        }
    
        //控制单元
        public void service(){
        
            Jedis jedis = new Jedis("127.0.0.1", 6379);
            String value = jedis.get("compid"+id);
            //判断是否为空
            try{
        
                if(value==null){
        
                    jedis.setex("compid"+id,5,Long.MAX_VALUE-num+"");
                }else{
        
                    Long val = jedis.incr("compid"+id);
                    business(id,num-Long.MAX_VALUE+val);
                }
            }catch (JedisDataException e){
        
                System.out.println("使用已经达到次数上限，请升级会员级别");
                return;
            }finally {
        
                jedis.close();
            }
        }
        //执行业务操作
        public void business(String id,Long val){
        
            System.out.println("用户"+id+"业务操作执行第"+val+"次");
        }
    }
    class MyThread extends Thread{
        
        Service service;
        public MyThread(String id,int num) {
        
            service=new Service(id,num);
        }
    
        @Override
        public void run() {
        
            while (true){
        
                service.service();
    //            service.service();
                try {
        
                    sleep(300L);
                } catch (InterruptedException e) {
        
                    e.printStackTrace();
                }
            }
        }
    }
    class Main{
        
        public static void main(String[] args) {
        
            MyThread thread1 = new MyThread("初级用户",10);
            MyThread thread2 = new MyThread("高级用户",30);
            thread1.start();
            thread2.start();
        }
    }

**Jedis简易工具类**  
基于连接池获取连接

JedisPool：Jedis提供的连接池技术  
poolConfig:连接池配置对象  
host:redis服务地址  
port:redis服务端口号

public JedisPool(GenericObjectPoolConfig poolConfig, String host, int port) {
        
     this(poolConfig, host, port, 2000, (String)null, 0, (String)null);
    }

reids.properties

redis.host=127.0.0.1
    redis.port=6379
    redis.maxTotal=30
    redis.maxIdle=10

public class JedisUtils {
        
        private static JedisPool jedisPool = null;
    
        static {
        
            ResourceBundle rb = ResourceBundle.getBundle("redis");//加载redis.properties
            String host = rb.getString("redis.host");
            int port = Integer.parseInt(rb.getString("redis.port"));
            JedisPoolConfig poolConfig = new JedisPoolConfig();
            poolConfig.setMaxTotal(Integer.parseInt(rb.getString("redis.maxTotal")));//设置一共连接数
            poolConfig.setMaxIdle(Integer.parseInt(rb.getString("redis.maxIdle")));//活动连接数
            jedisPool = new JedisPool(poolConfig, host, port);
        }
    
        public static Jedis getJedis() {
        
            return jedisPool.getResource();
        }
    
    
        public static void main(String[] args) {
        
            Jedis jedis = getJedis();
            System.out.println(jedis);
        }
    }

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