Redis数据库 | 事务、持久化

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Redis事务操作

Redis事务是一组命令的集合，这些命令会作为一个整体被执行，要么全部执行成功，要么全部执行失败；Redis事务通过MULTI、EXEC、DISCARD和WATCH四个命令来实现

MULTI：开启一个新的事务

EXEC：提交事务

DISCARD：取消事务

WATCH：监控一个或多个键，当这些键被其他客户端修改时，当前事务会被中断

Redis乐观锁

乐观锁是一种并发控制机制，它假设冲突的概率比较小，因此不会在访问共享资源时加锁，而是在更新时检查数据是否被其他进程修改过

Redis悲观锁

悲观锁是指在对共享资源进行操作时，认为其他线程或进程会对该资源进行修改，因此在操作前先加锁，以防止其他线程或进程的干扰

Jedis

Jedis是一个Java语言编写的Redis客户端库，用于在Java应用程序中连接和操作Redis数据库；Jedis库是开源的，可以通过Maven或Gradle等构建工具进行引入和使用

<dependency><groupId>com.github.luues.boot</groupId><artifactId>spring-boot-starter-jedis</artifactId><version>1.0.3.5.RELEASE</version>
</dependency>

Springboot集成Redis

• 依赖导入

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

• application.properties

#配置Redis
spring.redis.host=127.0.0.1
spring.redis.port=6379

• 测试

package com.wei;import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.core.RedisTemplate;@SpringBootTest
class SpringbootRedisApplicationTests {@Autowired(required = false)private RedisTemplate redisTemplate;@Testvoid contextLoads() {/*** RedisTemplate    操作不同是数据类型* opsForValue  操作String* opsForList   操作List* opsForHash   操作Hash* ……*//*** 操作数据库连接* redisTemplate.getConnectionFactory().getConnection();*/RedisConnection connection = redisTemplate.getConnectionFactory().getConnection();/*connection.flushDb(); 用于刷新查询缓存和结果集合，以提高查询性能connection.flushAll(); 用于刷新整个数据库，包括所有的表、视图、存储过程和触发器等*/connection.flushDb();connection.flushAll();}}

package com.wei;import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.core.RedisTemplate;@SpringBootTest
class SpringbootRedisApplicationTests {@Autowired(required = false)private RedisTemplate redisTemplate;@Testvoid contextLoads() {/*** RedisTemplate    操作不同是数据类型* opsForValue  操作String* opsForList   操作List* opsForHash   操作Hash* ……*/redisTemplate.opsForValue().set("mykey","weishuo");System.out.println(redisTemplate.opsForValue().get("mykey"));}}

源码

• RedisAutoConfiguration.java

package org.springframework.boot.autoconfigure.data.redis;import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnSingleCandidate;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Import;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;@AutoConfiguration
@ConditionalOnClass({RedisOperations.class})
@EnableConfigurationProperties({RedisProperties.class})
@Import({LettuceConnectionConfiguration.class, JedisConnectionConfiguration.class})
public class RedisAutoConfiguration {public RedisAutoConfiguration() {}@Bean@ConditionalOnMissingBean(name = {"redisTemplate"})@ConditionalOnSingleCandidate(RedisConnectionFactory.class)public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {RedisTemplate<Object, Object> template = new RedisTemplate();template.setConnectionFactory(redisConnectionFactory);return template;}@Bean@ConditionalOnMissingBean@ConditionalOnSingleCandidate(RedisConnectionFactory.class)public StringRedisTemplate stringRedisTemplate(RedisConnectionFactory redisConnectionFactory) {return new StringRedisTemplate(redisConnectionFactory);}
}

• RedisProperties.java

public class RedisProperties {private int database = 0;private String url;private String host = "localhost";private String username;private String password;private int port = 6379;private boolean ssl;private Duration timeout;private Duration connectTimeout;private String clientName;private RedisProperties.ClientType clientType;private RedisProperties.Sentinel sentinel;private RedisProperties.Cluster cluster;private final RedisProperties.Jedis jedis = new RedisProperties.Jedis();private final RedisProperties.Lettuce lettuce = new RedisProperties.Lettuce();……
}

自定义配置类

• config/RedisConfig.java

package com.wei.config;import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
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.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;import java.net.UnknownHostException;@Configuration
@SuppressWarnings("all")
//镇压所有警告
public class RedisConfig {@Beanpublic RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory)throws UnknownHostException {
//      默认的连接配置，和源码保持一致即可RedisTemplate<String, Object> template = new RedisTemplate<>();template.setConnectionFactory(redisConnectionFactory);//        序列化配置
//        json序列化配置--JacksonJackson2JsonRedisSerializer<Object> objectJackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class);ObjectMapper objectMapper = new ObjectMapper();objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);objectJackson2JsonRedisSerializer.setObjectMapper(objectMapper);//       string的序列化StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();//       string的key和hash的key都采用string的序列化
//        value都采用Jackson的序列化//key采用string序列化方式template.setKeySerializer(stringRedisSerializer);//hash的key采用string序列化方式template.setHashKeySerializer(stringRedisSerializer);//value采用Jackson序列化方式template.setValueSerializer(objectJackson2JsonRedisSerializer);//hash的value采用Jackson序列化方式template.setHashValueSerializer(objectJackson2JsonRedisSerializer);return template;}
}

Redis工具类封装

utils/RedisUtil.java

package com.wei.utils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;import java.util.*;
import java.util.concurrent.TimeUnit;
@Component
public final class RedisUtil {@Autowiredprivate RedisTemplate<String, Object> redisTemplate;
// =============================common============================/*** 指定缓存失效时间* @param key 键* @param time 时间(秒)*/public boolean expire(String key, long time) {try {if (time > 0) {redisTemplate.expire(key, time, TimeUnit.SECONDS);}return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 根据key 获取过期时间* @param key 键 不能为null* @return 时间(秒) 返回0代表为永久有效*/public long getExpire(String key) {return redisTemplate.getExpire(key, TimeUnit.SECONDS);}/*** 判断key是否存在* @param key 键* @return true 存在 false不存在*/public boolean hasKey(String key) {try {return redisTemplate.hasKey(key);} catch (Exception e) {e.printStackTrace();return false;}}/*** 删除缓存* @param key 可以传一个值 或多个*/@SuppressWarnings("unchecked")public void del(String... key) {if (key != null && key.length > 0) {if (key.length == 1) {redisTemplate.delete(key[0]);} else {redisTemplate.delete((Collection<String>) CollectionUtils.arrayToList(key));}}}
// ============================String=============================/*** 普通缓存获取* @param key 键* @return 值*/public Object get(String key) {return key == null ? null : redisTemplate.opsForValue().get(key);}/*** 普通缓存放入* @param key 键* @param value 值* @return true成功 false失败*/public boolean set(String key, Object value) {try {redisTemplate.opsForValue().set(key, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 普通缓存放入并设置时间* @param key 键* @param value 值* @param time 时间(秒) time要大于0 如果time小于等于0 将设置无限期* @return true成功 false 失败*/public boolean set(String key, Object value, long time) {try {if (time > 0) {redisTemplate.opsForValue().set(key, value, time,TimeUnit.SECONDS);} else {set(key, value);}return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 递增* @param key 键* @param delta 要增加几(大于0)*/public long incr(String key, long delta) {if (delta < 0) {throw new RuntimeException("递增因子必须大于0");}return redisTemplate.opsForValue().increment(key, delta);}/*** 递减* @param key 键* @param delta 要减少几(小于0)*/public long decr(String key, long delta) {if (delta < 0) {throw new RuntimeException("递减因子必须大于0");}return redisTemplate.opsForValue().increment(key, -delta);}
// ================================Map=================================/*** HashGet* @param key 键 不能为null* @param item 项 不能为null*/public Object hget(String key, String item) {return redisTemplate.opsForHash().get(key, item);}/*** 获取hashKey对应的所有键值* @param key 键* @return 对应的多个键值*/public Map<Object, Object> hmget(String key) {return redisTemplate.opsForHash().entries(key);}/*** HashSet* @param key 键* @param map 对应多个键值*/public boolean hmset(String key, Map<String, Object> map) {try {redisTemplate.opsForHash().putAll(key, map);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** HashSet 并设置时间* @param key 键* @param map 对应多个键值* @param time 时间(秒)* @return true成功 false失败*/public boolean hmset(String key, Map<String, Object> map, long time) {try {redisTemplate.opsForHash().putAll(key, map);if (time > 0) {expire(key, time);}return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 向一张hash表中放入数据,如果不存在将创建** @param key 键* @param item 项* @param value 值* @return true 成功 false失败*/public boolean hset(String key, String item, Object value) {try {redisTemplate.opsForHash().put(key, item, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 向一张hash表中放入数据,如果不存在将创建** @param key 键* @param item 项* @param value 值* @param time 时间(秒) 注意:如果已存在的hash表有时间,这里将会替换原有的时间* @return true 成功 false失败*/public boolean hset(String key, String item, Object value, long time) {try {redisTemplate.opsForHash().put(key, item, value);if (time > 0) {expire(key, time);}return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 删除hash表中的值** @param key 键 不能为null* @param item 项 可以使多个 不能为null*/public void hdel(String key, Object... item) {redisTemplate.opsForHash().delete(key, item);}/*** 判断hash表中是否有该项的值** @param key 键 不能为null* @param item 项 不能为null* @return true 存在 false不存在*/public boolean hHasKey(String key, String item) {return redisTemplate.opsForHash().hasKey(key, item);}/*** hash递增 如果不存在,就会创建一个 并把新增后的值返回** @param key 键* @param item 项* @param by 要增加几(大于0)*/public double hincr(String key, String item, double by) {return redisTemplate.opsForHash().increment(key, item, by);}/*** hash递减** @param key 键* @param item 项* @param by 要减少记(小于0)*/public double hdecr(String key, String item, double by) {return redisTemplate.opsForHash().increment(key, item, -by);}
// ============================set=============================/*** 根据key获取Set中的所有值* @param key 键*/public Set<Object> sGet(String key) {try {return redisTemplate.opsForSet().members(key);} catch (Exception e) {e.printStackTrace();return null;}}/*** 根据value从一个set中查询,是否存在** @param key 键* @param value 值* @return true 存在 false不存在*/public boolean sHasKey(String key, Object value) {try {return redisTemplate.opsForSet().isMember(key, value);} catch (Exception e) {e.printStackTrace();return false;}}/*** 将数据放入set缓存** @param key 键* @param values 值 可以是多个* @return 成功个数*/public long sSet(String key, Object... values) {try {return redisTemplate.opsForSet().add(key, values);} catch (Exception e) {e.printStackTrace();return 0;}}/*** 将set数据放入缓存** @param key 键* @param time 时间(秒)* @param values 值 可以是多个* @return 成功个数*/public long sSetAndTime(String key, long time, Object... values) {try {Long count = redisTemplate.opsForSet().add(key, values);if (time > 0)expire(key, time);return count;} catch (Exception e) {e.printStackTrace();return 0;}}/*** 获取set缓存的长度** @param key 键*/public long sGetSetSize(String key) {try {return redisTemplate.opsForSet().size(key);} catch (Exception e) {e.printStackTrace();return 0;}}/*** 移除值为value的** @param key 键* @param values 值 可以是多个* @return 移除的个数*/public long setRemove(String key, Object... values) {try {Long count = redisTemplate.opsForSet().remove(key, values);return count;} catch (Exception e) {e.printStackTrace();return 0;}}
// ===============================list=================================/*** 获取list缓存的内容** @param key 键* @param start 开始* @param end 结束 0 到 -1代表所有值*/public List<Object> lGet(String key, long start, long end) {try {return redisTemplate.opsForList().range(key, start, end);} catch (Exception e) {e.printStackTrace();return null;}}/*** 获取list缓存的长度** @param key 键*/public long lGetListSize(String key) {try {return redisTemplate.opsForList().size(key);} catch (Exception e) {e.printStackTrace();return 0;}}/*** 通过索引 获取list中的值** @param key 键* @param index 索引 index>=0时， 0 表头，1 第二个元素，依次类推；index<0时，-1，表尾，-2倒数第二个元素，依次类推*/public Object lGetIndex(String key, long index) {try {return redisTemplate.opsForList().index(key, index);} catch (Exception e) {e.printStackTrace();return null;}}/*** 将list放入缓存** @param key 键* @param value 值*/public boolean lSet(String key, Object value) {try {redisTemplate.opsForList().rightPush(key, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 将list放入缓存* @param key 键* @param value 值* @param time 时间(秒)*/public boolean lSet(String key, Object value, long time) {try {redisTemplate.opsForList().rightPush(key, value);if (time > 0)expire(key, time);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 将list放入缓存** @param key 键* @param value 值* @return*/public boolean lSet(String key, List<Object> value) {try {redisTemplate.opsForList().rightPushAll(key, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 将list放入缓存** @param key 键* @param value 值* @param time 时间(秒)* @return*/public boolean lSet(String key, List<Object> value, long time) {try {redisTemplate.opsForList().rightPushAll(key, value);if (time > 0)expire(key, time);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 根据索引修改list中的某条数据** @param key 键* @param index 索引* @param value 值* @return*/public boolean lUpdateIndex(String key, long index, Object value) {try {redisTemplate.opsForList().set(key, index, value);return true;} catch (Exception e) {e.printStackTrace();return false;}}/*** 移除N个值为value** @param key 键* @param count 移除多少个* @param value 值* @return 移除的个数*/public long lRemove(String key, long count, Object value) {try {Long remove = redisTemplate.opsForList().remove(key, count,value);return remove;} catch (Exception e) {e.printStackTrace();return 0;}}
}

Redis持久化

Redis 持久化的主要作用是将 Redis 的数据持久化到磁盘中，以防止 Redis 在内存中的数据意外丢失或者系统宕机导致的数据丢失，保证数据的可靠性和持久性；Redis 提供了两种持久化方式，分别是 RDB 和 AOF

RDB持久化

RDB 持久化：将 Redis 在内存中的数据定期写入磁盘中的快照文件，可以通过配置定期保存快照的时间间隔，也可以手动执行保存操作；RDB 持久化的优点是占用内存小，恢复数据速度快，适用于数据量较大，但是对数据实时性要求不高的场景

AOF持久化

AOF 持久化：将 Redis 的所有写操作都记录在一个日志文件中，可以通过配置日志文件的同步方式，确保数据的可靠性和实时性。AOF 持久化的优点是数据实时性高，可靠性强，适用于数据对实时性要求较高的场景

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