jedis

Does Redis only allow string representation but not numeric value

感情迁移 提交于 2019-12-05 02:22:36
I am getting mixed answers on my research here. Can someone verify that the Redis Server can only store representation of any numerical values? For instance, if I use a Java client (Jedis) with a double type in lpush, do I need to convert it to the equivalent of a string type before sending to Redis? Or is there a way to I can send over an actual numeric type like a double? If so, is there any example code on how to accomplish this? Thanks Redis stores everything in string or in its string representation. Even functions like INCR work by first parsing it into INTEGER then performing the

Using jedis How to cache Java object

左心房为你撑大大i 提交于 2019-12-05 01:38:49
Using Redis Java client Jedis How can I cache Java Object? you should convert your object as a json string to store it, then read the json and transform it back to your object. you can use Gson in order to do so. //store Gson gson = new Gson(); String json = gson.toJson(myObject); jedis.set(key,json); //restore String json = jedis.get(key); MyObject object=gson.fromJson(json, MyObject.class); You can't store objects directly into redis. So convert the object into String and then put it in Redis. In order to do that your object must be serialized. Convert the object to ByteArray and use some

基于redis实现购物车基本功能

*爱你&永不变心* 提交于 2019-12-04 23:49:15
1.准备工作: 数据库表设计 (yj_product_specification:商品规格表,用户表,商品表等 {没有规格表,只有规格值表,}), 测试工具:POSTMAN redis客户端:Redis Desktop Manager 其他的工具 我就不一 一说了 。 逻辑处理 : 购物车基本功能: 1.购物车列表 2.加入购物车 3.删除购物车某个商品 4.清空购物车 首先来分析一下加入购物车,这也是购物车中最难的功能(个人认为) 加入购物车时 我们要考虑到 对于一个客户来说 不同规格,不同商品 ,在内存中应该怎么处理 , 必要的几个参数 首先用户信息要得到(mem_Id),商品的信息(prd_id),商品所对应规格值的id,这个信息我们都要取到,我们还要考虑对于不同用户,不同的信息,在redis要怎么存储。redis的类型我就不在这里说了。我在redis做的划分是 以用户的id作为redis的key 当然对于不同商品来说 我们还要注意一个商品的不同规格,数量都是要区分的(我们是用hash来存储的),而且还是保证hash的key唯一。如果说我们把hash的key由商品id,规格值 等共同组成的话 那么这样的话 我们这样就可以很容易就区分的清楚。对于前端传过来的参数都是固定,所以我们直接用一个实体来接收 用debug看一下 这个cart里面是什么东西 注意看一下这个那个多信息拼装的

Redis实战--Jedis实现分布式锁

孤街醉人 提交于 2019-12-04 23:01:33
echo编辑整理,欢迎转载,转载请声明文章来源。欢迎添加echo微信(微信号:t2421499075)交流学习。 百战不败,依不自称常胜,百败不颓,依能奋力前行。——这才是真正的堪称强大!!! 分布式锁的基本要求 互斥 没有死锁 我持有的锁只能被我释放 分布式锁的释放和获取代码实现 package com.example.echo.redis.distlock; import redis.clients.jedis.Jedis; import java.util.Collections; /** * @author XLecho * Date 2019/11/18 0018 * Time 21:14 */ public class DistLock { private static final String LOCK_SUCCESS = "OK"; private static final String SET_IF_NOT_EXIST = "NX"; private static final String SET_WITH_EXPIRE_TIME = "PX"; private static final Long RELEASE_SUCCESS = 1L; /** * 尝试获取分布式锁 * * @param jedis redis客户端 * @param lockKey 锁 *

Redis实战--使用Jedis实现百万数据秒级插入

情到浓时终转凉″ 提交于 2019-12-04 23:00:37
echo编辑整理,欢迎转载,转载请声明文章来源。欢迎添加echo微信(微信号:t2421499075)交流学习。 百战不败,依不自称常胜,百败不颓,依能奋力前行。——这才是真正的堪称强大!!! 当我们使用普通方法插入大量数据到Redis的时候,我们发现,我们的插入数据并没有Redis宣传的那么快,号称有10w吞吐量的Redis为什么会在我们插入大量的数据的时候很慢呢?这就是本文要做说明的地方 10w吞吐量,大量插入没有得到体现? Redis号称有10w的吞吐量,但是我们使用普通方法插入的时候,我们发现并没有达到这样的数据,主要原因是我们插入的时候多次连接操作,创建连接需要时间,同时,一个连接就会由一个数据包,多个数据包的传送网络并不能保证一致,这些都是影响我们大量数据插入性能的。 怎么样实现打完数据秒级插入? 使用Pipeline 实现代码如下: // 在pom依赖中添加jedis依赖 <dependency> <groupId>redis.clients</groupId> <artifactId>jedis</artifactId> <version>2.9.0</version> </dependency> // 使用jedis实现pipeline调用 public static void main(String[] args) { Jedis jedis = new

Redis之Read timed out

十年热恋 提交于 2019-12-04 22:24:35
Redis报错:redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeoutException: Read timed out 问题描述: 在阿里云linux服务器上(最便宜的那种。。。),使用redis缓存实现点赞功能报错,由于对redis不够深入以为是配置文件的问题,忽略了代码。。 异常信息: redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeoutException: Read timed out at redis.clients.jedis.Protocol.process(Protocol.java:79) at redis.clients.jedis.Protocol.read(Protocol.java:131) at redis.clients.jedis.Connection.getIntegerReply(Connection.java:188) at redis.clients.jedis.Jedis.sismember(Jedis.java:1266) 问题解决: 使用完jedis之后执行close() 事例: public String set(String

Redis - How the key HASH and SET and ZSET are related on the CrudRepository save?

一曲冷凌霜 提交于 2019-12-04 20:55:18
I am new to Redis and developing code using Spring Boot + Spring Data Redis example. When I saved the records, I see KEYS gets created and out of these keys 4 are HASH , 1 ZSET and all others are SET . I did not see in the Spring docs, meaning of each KEY is getting saved. . 127.0.0.1:6379> KEYS * 1) "persons:c5cfd49d-6688-4b83-a9b7-be55dd1c36ad" 2) "persons:firstname:bran" 3) "persons:39e14dae-fa23-4935-948f-1922d668d1c2" 4) "persons:f0b6dd26-8922-4a36-bd2a-792a17dddff7" 5) "persons:address.city:Achalpur" 6) "persons:e493385a-64ae-42be-8398-51757153d273:idx" 7) "persons:053cdfea-e430-4e1c

Redis behavior with multiple concurrent programs doing read/del on the same hash key

淺唱寂寞╮ 提交于 2019-12-04 17:52:32
I've a program ( program_1 ) (Jedis-based) that writes to a Redis HASH ( KEY_1 ) on a regular basis. I've another program ( program_2 ) (separate JVM process) that executes periodically, and in a Redis transaction does the following: Transaction transaction = redis.multi(); //get the current entity table Response<Map<String, String>> currentEntityTableResponse = transaction.hgetAll(KEY_1); transaction.del(KEY_1); transaction.exec(); My assumption is when program_2 has deleted the HASH (with KEY_1) the next time program_1 runs it will create the HASH again. Is this correct ? Eli Yes. Redis is

Java连接Redis

旧街凉风 提交于 2019-12-04 13:29:53
1.启动本地Redis服务 打开cmd窗口,cd到redis安装路径,输入redis-server.exe redis.windows.conf启动redis服务 2.编写java代码 代码如下: package Data; import redis.clients.jedis.Jedis; import java.util.Set; public class TestRedis { public static void main(String[] args) { System.out.println("---连接redis---"); Jedis jedis = new Jedis("127.0.0.1", 6379); //jedis.auth("123456"); //System.out.println("连接成功"); //System.out.println("服务正在运行:"+jedis.ping()); jedis.select(0); System.out.println("\n---hash---"); jedis.hset("test", "name", "lucy"); jedis.hset("test", "age", "18"); Set<String> k1 = jedis.hkeys("test"); System.out.println(k1);

Redis/Jedis no single point of failure and automated failover

早过忘川 提交于 2019-12-04 11:53:53
问题 In a simple situation with 3 servers with 1 master and 2 slaves with no sharding. Is there a proven solution with java and Jedis that has no single point of failure and will automatically deal with a single server going down be that master or slave(automated failover). e.g. promoting masters and reseting after the failure without any lost data. It seems to me like it should be a solved problem but I can't find any code on it just high level descriptions of possible ways to do it. Who actually