Redis

1、关系型与非关系型数据库对比

2、非关系型数据库优点及应用场景

分布式ID

3、BitMap 存二进制数据（0101010）、HyperLogLog（数据统计（少））

4、redis的命令参数

（1）String字符串命令

（2）key键命令

（3）List命令

关注，收藏，点赞，队列

（4）set命令

 (5)zset 有序不重复

应用：排行榜、热搜

ZREVRANGE salary 0 -1

（6）Hash

 5、redis原始语句

6、问题

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7、java链接redis的客服端

8、日志输出

9、键通过RestTeplate操作，值通过ValueOperations及以下去操作

10、redis配置

（1）导包

<!--        redis依赖包-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>

（2）配置序列化

package com.smart.community.youth.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

@Configuration
public class RedisConfig {

    /**
     * 序列化配置
     * json序列化 jdk的序列化
     * @param connectionFactory
     * @return
     */
    @Bean
    public RedisTemplate<String,Object> redisTemplate(RedisConnectionFactory connectionFactory){
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();

        redisTemplate.setConnectionFactory(connectionFactory);

        /**
         * 四个设置
         * 1 键的序列化
         * 2 值的序列
         */
        StringRedisSerializer keyRedisSerializer = new StringRedisSerializer();
        redisTemplate.setStringSerializer(keyRedisSerializer);
        redisTemplate.setHashKeySerializer(keyRedisSerializer);
        redisTemplate.setKeySerializer(keyRedisSerializer);

        GenericJackson2JsonRedisSerializer genericJackson2JsonRedisSerializer = new GenericJackson2JsonRedisSerializer();
        redisTemplate.setHashKeySerializer(genericJackson2JsonRedisSerializer);
        redisTemplate.setValueSerializer(genericJackson2JsonRedisSerializer);
        return redisTemplate;


    }

    @Bean
    public ValueOperations<String, Object> valueOperations(RedisTemplate<String, Object> redisTemplate) {
        return redisTemplate.opsForValue();
    }

}

（3）配置yml配置文件

server:
  port: 8089

spring:
  redis:
    host: 127.0.0.1
    database: 0
    port: 6379
    password: ""
    # 默认单位毫秒
    timeout: 5s
    # 连接池
    jedis:
      pool:
        #  最大连接数
        max-active: 10
        #  空闲连接数数
        max-idle: 8
        # 空闲最小链接数
        min-idle: 2
        max-wait: 3s
  profiles:
    active: "db,dev,swagger"

logging:
  level:
    "com.smart.community.youth": debug

（4）测试对象

package com.smart.community.youth.vo;

import lombok.Data;

@Data
public class UserVo {
    private String username;
}

（5）测试

package com.zw.data.redis.mapper;

import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.RedisTemplate;

import javax.annotation.Resource;
import java.time.Duration;
import java.util.concurrent.TimeUnit;

@SpringBootTest
@Slf4j
public class KeyRedisTemplateTest {
    @Resource
    RedisTemplate<String, Object> redisTemplate;

    @Test
    public void hasKey() {
        Boolean b = redisTemplate.hasKey("test:key:exists");
        Boolean delete = redisTemplate.delete("test:key:exists");
        redisTemplate.expire("test:key:exists", Duration.ofSeconds(1));
        redisTemplate.expire("test:key:exists", 1, TimeUnit.SECONDS);
        log.debug("" + b);
    }
}

package com.zw.data.redis.mapper;

import com.zw.data.redis.vo.SysUserVo;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;

import javax.annotation.Resource;
import java.time.Duration;

@SpringBootTest
public class StringRedisTemplateTest {
    @Resource
    RedisTemplate<String, Object> redisTemplate;
    @Resource
    ValueOperations<String, Object> valueOperations;

    // 设置永不过期
    // 设置过期时间  nx
    // 存在不设置值
    // 不存在就设置值
    @Test
    public void setTest() {
        valueOperations.set("test:str:set", "永不过期");
        valueOperations.set("test:str:set:ex", "设置过期时间", Duration.ofMinutes(10));
        // 键不存在则设置值
        valueOperations.setIfAbsent("test:str:set:nx", "键不存在则设置值");
        // 修改操作
        valueOperations.setIfPresent("test:str:set:nx", "键不存在则设置值");

        SysUserVo sysUserVo = new SysUserVo();
        sysUserVo.setUsername("admin");
        valueOperations.set("test:str:set:obj", sysUserVo);
    }

    @Test
    public void incr() {
        Long num = valueOperations.increment("test:str:set:incr");
        Long num1 = valueOperations.decrement("test:str:set:incr");

    }


}

11、Duration 时间类使用

还有1d（一天） 2h（2小时）那些

12、缓存的原理

通过AOP去缓存里面取，取key 类名+方法名+参数+特殊区分符

13、配置了Bean注入之后

这边引入一下就直接用了

14、把RedisTemplate那些方法封装到DAO中去