Redis如何存储对象

Redis存储对象

在以往面试中，多次被问到Redis怎么存储对象，我支支吾吾半天回答不上来，毕竟我只用过String类型，为了避免以后的尴尬，今天花点时间来整理一下。

本人用的Jedis客户端

首先引入依赖

    <dependency>
      <groupId>redis.clients</groupId>
      <artifactId>jedis</artifactId>
      <version>3.2.0</version>
    </dependency>

创建一个Jedis实例

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获取工具类
 */
public class JedisUtil { 
    private static JedisPool jedisPool;
    private static final Logger logger = LoggerFactory.getLogger(JedisUtil.class);
 
    static {
        // 初始化连接池
        JedisPoolConfig jedisPoolConfig = new JedisPoolConfig();
        jedisPoolConfig.setMaxTotal(20);
        jedisPoolConfig.setMaxIdle(10);
        jedisPool = new JedisPool(jedisPoolConfig, "127.0.0.1", 6379);
        logger.info("jedisPool连接池初始化====" + jedisPool);
    }
 
    /**
     * 获取一个Jedis实例
     * @return
     */
    public synchronized static Jedis getJedis(){
        Jedis jedis = jedisPool.getResource();
//        jedis.auth("123456");//密码
        return jedis;
    }
}

下面我们来实现存储对象

方式一：将对象转化为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：将对象序列化后存到redis

封装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;
    }
}

保存对象

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：将对象用Hash数据类型存储

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);

// 输出结果 [3,xiateng,123455]

注意：以序列化的方式存储的对象需要实现 Serializable 接口

Redis可以存储java对象吗

答案：是可以

但是你对象必须要序列化。

redis没有办法把一个没有序列化的对象存储到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;
    }
}

这样太麻烦了，并且存储中文会有乱码，那如何解决呢？只能重新定义一个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 改写redistemplate序列化规则
     * @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);
        // 创建一个json的序列化方式
        GenericJackson2JsonRedisSerializer jackson2JsonRedisSerializer = new GenericJackson2JsonRedisSerializer();
        // 设置value用jackjson进行处理
        redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);
        // 设置key用string序列化方式
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer);
        redisTemplate.afterPropertiesSet();
        return redisTemplate;
    }
}

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。