Redis如何存儲對象
Redis存儲對象
在以往面試中,多次被問到Redis怎麼存儲對象,我支支吾吾半天回答不上來,畢竟我隻用過String類型,為瞭避免以後的尷尬,今天花點時間來整理一下。
本人用的Jedis客戶端
首先引入依賴
<dependency> <groupId>redis.clients</groupId> <artifactId>jedis</artifactId> <version>3.2.0</version> </dependency>
創建一個Jedis實例
package com.xiateng.util; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import redis.clients.jedis.Jedis; import redis.clients.jedis.JedisPool; import redis.clients.jedis.JedisPoolConfig; /** * jedis獲取工具類 */ public class JedisUtil { private static JedisPool jedisPool; private static final Logger logger = LoggerFactory.getLogger(JedisUtil.class); static { // 初始化連接池 JedisPoolConfig jedisPoolConfig = new JedisPoolConfig(); jedisPoolConfig.setMaxTotal(20); jedisPoolConfig.setMaxIdle(10); jedisPool = new JedisPool(jedisPoolConfig, "127.0.0.1", 6379); logger.info("jedisPool連接池初始化====" + jedisPool); } /** * 獲取一個Jedis實例 * @return */ public synchronized static Jedis getJedis(){ Jedis jedis = jedisPool.getResource(); // jedis.auth("123456");//密碼 return jedis; } }
下面我們來實現存儲對象
方式一:將對象轉化為JSON字符串存入redis
Jedis jedis = JedisUtil.getJedis(); TUser tUser = new TUser(); tUser.setUserName("你好"); tUser.setPassword("2342342"); jedis.set("xiateng", JSON.toJSONString(tUser)); String sss = jedis.get("xiateng"); TUser ssss = JSON.parseObject(sss,TUser.class); jedis.del("xiateng"); System.out.println("---------------------------: "+ssss.toString());
方式二:將對象序列化後存到redis
封裝序列化跟反序列化方法
package com.xiateng.util; import java.io.*; public class SerializeUtil { /** * 序列化操作 * @param object * @return */ public static byte[] serialize(Object object){ ObjectOutputStream oos = null; ByteArrayOutputStream baos = null; try { // 序列化 baos = new ByteArrayOutputStream(); oos = new ObjectOutputStream(baos); oos.writeObject(object); byte[] bytes = baos.toByteArray(); return bytes; } catch (IOException e) { e.printStackTrace(); } return null; } /** * 反序列化操作 * @param bytes * @return */ public static Object unSerialize(byte[] bytes){ ByteArrayInputStream bais = null; try { bais = new ByteArrayInputStream(bytes); ObjectInputStream ois = new ObjectInputStream(bais); return ois.readObject(); } catch (IOException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } return null; } }
保存對象
Jedis jedis = JedisUtil.getJedis(); jedis.set("code".getBytes(), SerializeUtil.serialize(tUser)); byte[] bytes = jedis.get("code".getBytes()); TUser o = (TUser)SerializeUtil.unSerialize(bytes); jedis.del("code"); System.out.println(o.toString());
方式三:將對象用Hash數據類型存儲
Jedis jedis = JedisUtil.getJedis(); jedis.hset("user", "id", "3"); jedis.hset("user", "name", "xiateng"); jedis.hset("user", "password", "123455"); jedis.hget("user","id"); List<String> user = jedis.hmget("user", new String[]{"id","name","password"}); System.out.println("---------------------------: "+user); // 輸出結果 [3,xiateng,123455]
註意:以序列化的方式存儲的對象需要實現 Serializable 接口
Redis可以存儲java對象嗎
答案:是可以
但是你對象必須要序列化。
redis沒有辦法把一個沒有序列化的對象存儲到redis中。
package com.kuangstudy.entiy; import lombok.Data; public class User implements java.io.Serializable{ private Integer id; private String nickname; private String password; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getNickname() { return nickname; } public void setNickname(String nickname) { this.nickname = nickname; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }
這樣太麻煩瞭,並且存儲中文會有亂碼,那如何解決呢?隻能重新定義一個redisTemplate
package com.kuangstudy.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.serializer.GenericJackson2JsonRedisSerializer; import org.springframework.data.redis.serializer.StringRedisSerializer; @Configuration public class RedisConfiguration { /** * @return org.springframework.data.redis.core.RedisTemplate<java.lang.String, java.lang.Object> * @Author 徐柯 * @Description 改寫redistemplate序列化規則 * @Date 13:20 2021/5/20 * @Param [redisConnectionFactory] **/ @Bean public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) { RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>(); redisTemplate.setConnectionFactory(redisConnectionFactory); // 創建一個json的序列化方式 GenericJackson2JsonRedisSerializer jackson2JsonRedisSerializer = new GenericJackson2JsonRedisSerializer(); // 設置value用jackjson進行處理 redisTemplate.setValueSerializer(jackson2JsonRedisSerializer); // 設置key用string序列化方式 redisTemplate.setKeySerializer(new StringRedisSerializer()); redisTemplate.setHashKeySerializer(new StringRedisSerializer()); redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer); redisTemplate.afterPropertiesSet(); return redisTemplate; } }
以上為個人經驗,希望能給大傢一個參考,也希望大傢多多支持WalkonNet。
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