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2021
11-19

redis 存储对象的方法对比分析

redis 存储对象的方法对比

问题背景:

原来项目里面全部是直接redis存储对象的json数据,需要频繁的序列化和反序列化,后来考虑更换项目中的redis存储对象为hash对象存储的,但是获取后不能方便的set get操作,很是蛋疼,怎么才能解决这个问题呢?

1.1 直接存储对象的json

存放redis的时候,直接先用fastJson 或者 jackJson或者Gson把对象序列化为json数据,然后用直接存放,key表示用户id或许和openid,value则是对象的json数据

public String get(String key) {
Object value = redisTemplate.boundValueOps(key).get();
return (String) value;
}
public void set(String key, String json) {
if (json == null) {
return;
}
redisTemplate.boundValueOps(key).set(json);
}

优点:虽然需要序列化和反序列化,但是可以直接操作对象的方法,方便快捷

缺点:需要序列化和反序列化,并且修改单个字段,需要获取整个json,修改后,序列化保存,浪费空间,浪费时间,效率低

1.2 采用redis hash key field value 存储

key代表主键,比如用户id,或者openId,value是一个map,对应各个字段的属性和值

存放单个字段

public void hset(String key, String field, String obj) {
redisTemplate.boundHashOps(key).put(field,obj);
}

存放整个:

public void hSetMap(String key,Map<Object,Object> map){
redisTemplate.boundHashOps(key).putAll(map);
}

优点:存储方方便,节省内存空间,并且可以直接对单个字段修改,而不用获取整个对象,效率高

缺点:获取value后,是个map,不能方便的直接调用(set get)处理,需要手动map.get(filed)或者map.put(field,value)

1.3 如何解决redis hash存储对象的操作方便性问题

其实关于map和pojo的转换问题,网上给出了利用反射做的转换方法,但是加上了转换和反转,这和序列化和反序列化的问题一样了,效率问题,也不敢指直接用,纠结,思考再三,还是先维持代码不动了,以后考虑好了再说,或者广发网友有啥好解决方法,请多多指教哈!

Redis存储对象的三种方式

一、 将对象序列化后保存到Redis

序列化工具类实现

public class SerializeUtil {
    /*
     * 序列化
     * */
    public static byte[] serizlize(Object object){
        ObjectOutputStream oos = null;
        ByteArrayOutputStream baos = null;
        try {
            baos = new ByteArrayOutputStream();
            oos = new ObjectOutputStream(baos);
            oos.writeObject(object);
            byte[] bytes = baos.toByteArray();
            return bytes;
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            try {
                if(baos != null){
                    baos.close();
                }
                if (oos != null) {
                    oos.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return null;
    }
    /*
     * 反序列化
     * */
    public static Object deserialize(byte[] bytes){
        ByteArrayInputStream bais = null;
        ObjectInputStream ois = null; 
        try{
            bais = new ByteArrayInputStream(bytes);
            ois = new ObjectInputStream(bais);
            return ois.readObject();
        }catch(Exception e){
            e.printStackTrace();
        }finally {
            try {
 
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return null;
    }
}

获取jedis实例

public class RedisConnection {
    private static String HOST = "127.0.0.1";
    private static int PORT = 6379;
    private static int MAX_ACTIVE = 1024;
    private static int MAX_IDLE = 200;
    private static int MAX_WAIT = 10000;
 
    private static JedisPool jedisPool = null;
 
    /*
     * 初始化redis连接池
     * */
    private static void initPool(){
        try {
            JedisPoolConfig config = new JedisPoolConfig();
            config.setMaxTotal(MAX_ACTIVE);//最大连接数
            config.setMaxIdle(MAX_IDLE);//最大空闲连接数
            config.setMaxWaitMillis(MAX_WAIT);//获取可用连接的最大等待时间
 
            jedisPool = new JedisPool(config, HOST, PORT);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    /*
     * 获取jedis实例
     * */
    public synchronized static Jedis getJedis() {
        try {
            if(jedisPool == null){
                initPool();
            }
            Jedis jedis = jedisPool.getResource();
            jedis.auth("redis");//密码
            return jedis;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}

redis操作类

public class RedisOps {
    public static void set(String key,String value){
        Jedis jedis = RedisConnection.getJedis();
        jedis.set(key, value);
        jedis.close();
    }
    public static String get(String key){
        Jedis jedis = RedisConnection.getJedis();
        String value = jedis.get(key);
        jedis.close();
        return value;
    }
    public static void setObject(String key,Object object){
        Jedis jedis = RedisConnection.getJedis();
        jedis.set(key.getBytes(), SerializeUtil.serizlize(object));
        jedis.close();
    }
    public static Object getObject(String key){
        Jedis jedis = RedisConnection.getJedis();
        byte[] bytes = jedis.get(key.getBytes());
        jedis.close();
        return SerializeUtil.deserialize(bytes);
    }
}

User对象

public class User implements Serializable{
    private static final long serialVersionUID = -3210884885630038713L;
    private int id;
    private String name;
    public User(){
 
    }
    public User(int id,String name){
        this.id = id;
        this.name = name;
    }
    //setter和getter方法
}

测试

public class RedisTest {
 
    @Test
    public void testString(){
        RedisOps.set("user:1", "sisu");
        String user = RedisOps.get("user:1");
        Assert.assertEquals("sisu", user);
    }
 
    @Test
    public void testObject(){
        RedisOps.setObject("user:2",new User(2,"lumia"));
        User user = (User)RedisOps.getObject("user:2");
        Assert.assertEquals("lumia", user.getName());
    } 
}

二、将对象用FastJSON转为JSON字符串后存储

redis操作类

public class RedisOps {
    public static void setJsonString(String key,Object object){
        Jedis jedis = RedisConnection.getJedis();
        jedis.set(key, JSON.toJSONString(object));
        jedis.close();
    }
    public static Object getJsonObject(String key,Class clazz){
        Jedis jedis = RedisConnection.getJedis();
        String value = jedis.get(key);
        jedis.close();
        return JSON.parseObject(value,clazz);
    }
}

测试

 @Test
    public void testObject2(){
        RedisOps.setJsonString("user:3", new User(3,"xiaoming"));
        User user = (User)RedisOps.getJsonObject("user:3",User.class);
        Assert.assertEquals("xiaoming", user.getName());
    }

三、将对象用Hash数据类型存储

redis操作类

public class RedisOps {
    public static void hSet(String key,String value){
        Jedis jedis = RedisConnection.getJedis();
        jedis.hSet(key, value);
        jedis.close();
    }
    public static String hGet(String key){
        Jedis jedis = RedisConnection.getJedis();
        String value = jedis.hGet(key);
        jedis.close();
        return value;
    }
}

测试

 @Test
    public void testObject3(){
     //存
        RedisOps.hSet("user:3","id","3");
        RedisOps.hSet("user:3","name","xiaoming");
        
        //取
        String id =  RedisOps..hGet("user:3","id");
        String name = RedisOps.hGet("user:3","name");
        Assert.assertEquals("3", id);
        Assert.assertEquals("xiaoming", name);        
    }

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自学编程网。

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