Redis實(shí)戰(zhàn)之Jedis使用技巧詳解
更新時間：2022年12月22日 10:35:06 作者：鴨血粉絲Tang
Jedis?是老牌的?Redis?的?Java?客戶端，提供了比較全面的?Redis?命令的操作支持，也是目前使用最廣泛的客戶端。這篇文章主要為大家詳細(xì)介紹了Jedis的使用技巧，需要的可以參考一下
一、摘要
在上一篇文章中，我們詳細(xì)的介紹了 redis 的安裝和常見的操作命令，以及可視化工具的介紹。
剛知道服務(wù)端的操作知識，還是遠(yuǎn)遠(yuǎn)不夠的，如果想要真正在項(xiàng)目中得到應(yīng)用，我們還需要一個 redis 的客戶端，然后將其集成到項(xiàng)目中，讓程序自動根據(jù)我們的業(yè)務(wù)需要自動處理。
基于 redis 開放的通信協(xié)議，大神們紛紛開發(fā)了各種語言的 redis 客戶端，有 c、c++、java、python、php、nodeJs 等等開發(fā)語言的客戶端，準(zhǔn)確來說其實(shí)這些客戶端都是基于 redis 命令做了一層封裝，然后打包成工具以便大家更佳方便的操作 redis，以 Java 項(xiàng)目為例，使用最廣的就是以下三種客戶端：
- Jedis
- Lettuce
- Redisson
由于篇幅的原因，我們分三篇文章來詳細(xì)的講解每個客戶端的使用方式以及它的優(yōu)缺點(diǎn)。
廢話不多說，直奔主題！
二、Jedis
Jedis 是老牌的 Redis 的 Java 客戶端，提供了比較全面的 Redis 命令的操作支持，也是目前使用最廣泛的客戶端。
官方網(wǎng)址如下：
https://github.com/redis/jedis
如何在項(xiàng)目中集成 Jedis 呢？請看下文！
2.1、基本使用
首先創(chuàng)建一個普通的 Maven 項(xiàng)目，然后添加Jedis依賴包！
<dependency> ??<groupId>redis.clients</groupId> ??<artifactId>jedis</artifactId> ??<version>3.9.0</version> </dependency>
然后創(chuàng)建一個簡單的測試，即可實(shí)現(xiàn)連接！
public?class?JedisMain?{
????public?static?void?main(String[]?args)?{
????????//?1.構(gòu)造一個?Jedis?對象，因?yàn)檫@里使用的默認(rèn)端口?6379，所以不用配置端口
????????Jedis?jedis?=?new?Jedis("127.0.0.1",?6379);
????????//?2.密碼認(rèn)證
????????jedis.auth("111111");
????????//?3.測試是否連接成功
????????String?ping?=?jedis.ping();
????????//?4.返回?pong?表示連接成功
????????System.out.println(ping);
????}
}
對于 Jedis 而言，一旦連接上了 Redis 服務(wù)器，剩下的操作就非常容易了，由于 Jedis 中的 API 和 Redis 的命令高度一致，所以，Jedis 中的方法見名知意，直接使用即可。
2.2、連接池
雖然 redis 服務(wù)端是單線程操作，但是在實(shí)際項(xiàng)目中，使用 Jedis 對象來操作 redis 時，每次操作都需要新建/關(guān)閉 TCP 連接，連接資源開銷很高，同時 Jedis 對象的個數(shù)不受限制，在極端情況下可能會造成連接泄漏，同時 Jedis 存在多線程不安全的問題。
為什么說 Jedis 線程不安全，更加詳細(xì)的原因可以參考:使用Jedis面臨的非線程安全問題詳解
所以我們需要將 Jedis 交給線程池來管理，使用 Jedis 對象時，從連接池獲取 Jedis，使用完成之后，再還給連接池。
在使用之前，需要添加common-pool線程池依賴包！
<dependency> ?<groupId>org.apache.commons</groupId> ?<artifactId>commons-pool2</artifactId> ?<version>2.11.1</version> </dependency>
創(chuàng)建一個簡單的使用線程池測試用例。
public?class?JedisPoolMain?{
????public?static?void?main(String[]?args)?{
????????//?1.?構(gòu)造一個?Jedis?連接池
????????JedisPool?pool?=?new?JedisPool("127.0.0.1",?6379);
????????//?2.?從連接池中獲取一個?Jedis?連接
????????Jedis?jedis?=?pool.getResource();
????????jedis.auth("111111");
????????//?3.?Jedis?操作
????????String?ping?=?jedis.ping();
????????System.out.println(ping);
????????//?4.?歸還連接
????????jedis.close();
????}
}
2.3、連接池配置
在實(shí)際的使用過程中，我們常常會這樣來初始化線程池JedisPool，詳細(xì)代碼如下：
public?class?RedisPoolUtils?{
????private?static?JedisPool?jedisPool?=?null;
????/**
?????*?redis服務(wù)器地址
?????*/
????private?static?String?addr?=?"127.0.0.1";
????/**
?????*?redis服務(wù)器端口
?????*/
????private?static?int?port?=?6379;
????/**
?????*?redis服務(wù)器密碼
?????*/
????private?static?String?auth?=?"111111";
????static{
????????try?{
????????????JedisPoolConfig?config?=?new?JedisPoolConfig();
????????????//連接耗盡時是否阻塞,?false報(bào)異常,ture阻塞直到超時,?默認(rèn)true
????????????config.setBlockWhenExhausted(true);
????????????//設(shè)置的逐出策略類名,?默認(rèn)DefaultEvictionPolicy(當(dāng)連接超過最大空閑時間,或連接數(shù)超過最大空閑連接數(shù))
????????????config.setEvictionPolicyClassName("org.apache.commons.pool2.impl.DefaultEvictionPolicy");
????????????//是否啟用pool的jmx管理功能,?默認(rèn)true
????????????config.setJmxEnabled(true);
????????????//MBean?ObjectName?=?new?ObjectName("org.apache.commons.pool2:type=GenericObjectPool,name="?+?"pool"?+?i);?默認(rèn)為"pool",?JMX不熟,具體不知道是干啥的...默認(rèn)就好.
????????????config.setJmxNamePrefix("pool");
????????????//是否啟用后進(jìn)先出,?默認(rèn)true
????????????config.setLifo(true);
????????????//最大空閑連接數(shù),?默認(rèn)8個
????????????config.setMaxIdle(8);
????????????//最大連接數(shù),?默認(rèn)8個
????????????config.setMaxTotal(8);
????????????//獲取連接時的最大等待毫秒數(shù)(如果設(shè)置為阻塞時BlockWhenExhausted),如果超時就拋異常,?小于零:阻塞不確定的時間,??默認(rèn)-1
????????????config.setMaxWaitMillis(-1);
????????????//逐出連接的最小空閑時間?默認(rèn)1800000毫秒(30分鐘)
????????????config.setMinEvictableIdleTimeMillis(1800000);
????????????//最小空閑連接數(shù),?默認(rèn)0
????????????config.setMinIdle(0);
????????????//每次逐出檢查時?逐出的最大數(shù)目?如果為負(fù)數(shù)就是?:?1/abs(n),?默認(rèn)3
????????????config.setNumTestsPerEvictionRun(3);
????????????//對象空閑多久后逐出,?當(dāng)空閑時間>該值?且?空閑連接>最大空閑數(shù)?時直接逐出,不再根據(jù)MinEvictableIdleTimeMillis判斷??(默認(rèn)逐出策略)
????????????config.setSoftMinEvictableIdleTimeMillis(1800000);
????????????//在獲取連接的時候檢查有效性,?默認(rèn)false
????????????config.setTestOnBorrow(false);
????????????//在空閑時檢查有效性,?默認(rèn)false
????????????config.setTestWhileIdle(false);
????????????//逐出掃描的時間間隔(毫秒)?如果為負(fù)數(shù),則不運(yùn)行逐出線程,?默認(rèn)-1
????????????config.setTimeBetweenEvictionRunsMillis(-1);
????????????jedisPool?=?new?JedisPool(config,?addr,?port,?3000,?auth);
????????}?catch?(Exception?e)?{
????????????e.printStackTrace();
????????}
????}
????/**
?????*?獲取?Jedis?資源
?????*?@return
?????*/
????public?static?Jedis?getJedis()?{
????????if?(jedisPool?!=?null)?{
????????????return?jedisPool.getResource();
????????}
????????return?null;
????}
????/**
?????*?釋放Jedis資源
?????*/
????public?static?void?close(final?Jedis?jedis)?{
????????if?(jedis?!=?null)?{
????????????jedis.close();
????????}
????}
}
簡單測試
public?static?void?main(String[]?args)?throws?InterruptedException?{
????//獲取?jedis?客戶端
????Jedis?jedis?=?RedisPoolUtils.getJedis();
????System.out.println("清空數(shù)據(jù)："+jedis.flushDB());
????System.out.println("判斷某個鍵是否存在："+jedis.exists("username"));
????System.out.println("新增<'username','xmr'>的鍵值對："+jedis.set("username",?"xmr"));
????System.out.println(jedis.exists("username"));
????System.out.println("新增<'password','password'>的鍵值對："+jedis.set("password",?"123"));
????System.out.print("系統(tǒng)中所有的鍵如下：");
????Set<String>?keys?=?jedis.keys("*");
????System.out.println(keys);
????System.out.println("刪除鍵password:"+jedis.del("password"));
????System.out.println("判斷鍵password是否存在："+jedis.exists("password"));
????System.out.println("設(shè)置鍵username的過期時間為5s:"+jedis.expire("username",?8L));
????TimeUnit.SECONDS.sleep(1);
????System.out.println("查看鍵username的剩余生存時間："+jedis.ttl("username"));
????System.out.println("移除鍵username的生存時間："+jedis.persist("username"));
????System.out.println("查看鍵username的剩余生存時間："+jedis.ttl("username"));
????System.out.println("查看鍵username所存儲的值的類型："+jedis.type("username"));
????RedisPoolUtils.close(jedis);
}
運(yùn)行結(jié)果如下：
清空數(shù)據(jù)：OK
判斷某個鍵是否存在：false
新增<'username','xmr'>的鍵值對：OK
true
新增<'password','password'>的鍵值對：OK
系統(tǒng)中所有的鍵如下：[password, username]
刪除鍵password:1
判斷鍵password是否存在：false
設(shè)置鍵username的過期時間為5s:1
查看鍵username的剩余生存時間：7
移除鍵username的生存時間：1
查看鍵username的剩余生存時間：-1
查看鍵username所存儲的值的類型：string
2.4、字符串常用 API 操作
public?class?RedisClientUtil?{
????private?static?final?Logger?log?=?LoggerFactory.getLogger(RedisClientUtil.class);
????/**
?????*?獲取指定key的值,如果key不存在返回null
?????*?返回值：返回?key?的值，如果?key?不存在時，返回?nil
?????*?@param?key
?????*?@return
?????*/
????public?static?String?get(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.get(key);
????????}?catch?(Exception?e){
????????????log.error("get命令操作失敗，請求參數(shù)：{}",?key,e);
????????}
????????return?null;
????}
????/**
?????*?設(shè)置key的值為value
?????*?返回值：操作成功完成時返回?OK
?????*?@param?key
?????*?@return
?????*/
????public?static?String?set(String?key,?String?value)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.set(key,?value);
????????}?catch?(Exception?e){
????????????log.error("set命令操作失敗，參數(shù)key：{}，參數(shù)value：{}",?key,?value,e);
????????}
????????return?null;
????}
????/**
?????*?刪除指定的key，返回值：被刪除?key?的數(shù)量
?????*?返回值：被刪除?key?的數(shù)量
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?del(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????Long?result?=?jedis.del(key);
????????????return?jedis.del(key);
????????}?catch?(Exception?e){
????????????log.error("del命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?0L;
????}
????/**
?????*?通過key向指定的value值追加值
?????*?返回值：追加指定值之后，?key中字符串的長度
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?append(String?key,?String?value)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.append(key,?value);
????????}?catch?(Exception?e){
????????????log.error("append命令操作失敗，參數(shù)key：{}，參數(shù)value：{}",?key,?value,e);
????????}
????????return?0L;
????}
????/**
?????*?判斷key是否存在
?????*?返回值：true/false
?????*?@param?key
?????*?@return
?????*/
????public?static?Boolean?exists(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.exists(key);
????????}?catch?(Exception?e){
????????????log.error("exists命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?false;
????}
????/**
?????*?設(shè)置key的超時時間為seconds
?????*?返回值：若?key?存在返回?1?，否則返回?0
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?expire(String?key,?long?seconds)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.expire(key,?seconds);
????????}?catch?(Exception?e){
????????????log.error("expire命令操作失敗，參數(shù)key：{}，參數(shù)seconds：{}",?key,?seconds,e);
????????}
????????return?0L;
????}
????/**
?????*?返回?key?的剩余過期時間（單位秒）
?????*?返回值：當(dāng)?key?不存在時，返回?-2?。?當(dāng)?key?存在但沒有設(shè)置剩余生存時間時，返回?-1?。?否則，以秒為單位，返回?key?的剩余生存時間
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?ttl(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.ttl(key);
????????}?catch?(Exception?e){
????????????log.error("ttl命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?0L;
????}
????/**
?????*?設(shè)置指定key的值為value,當(dāng)key不存在時才設(shè)置
?????*?返回值：設(shè)置成功返回?1，設(shè)置失敗返回?0
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?setnx(String?key,?String?value)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.setnx(key,?value);
????????}?catch?(Exception?e){
????????????log.error("setnx命令操作失敗，參數(shù)key：{}，參數(shù)value：{}",?key,?value,e);
????????}
????????return?0L;
????}
????/**
?????*?設(shè)置指定key的值為value,并設(shè)置過期時間
?????*?返回值：設(shè)置成功時返回?OK
?????*?@param?key
?????*?@return
?????*/
????public?static?String?setex(String?key,?String?value,?long?seconds)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.setex(key,?seconds,?value);
????????}?catch?(Exception?e){
????????????log.error("setex命令操作失敗，參數(shù)key：{}，參數(shù)value：{}",?key,?value,e);
????????}
????????return?null;
????}
????/**
?????*?通過key?和offset?從指定的位置開始將原先value替換
?????*?返回值：被修改后的字符串長度
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?setrange(String?key,?int?offset,?String?value)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.setrange(key,?offset,?value);
????????}?catch?(Exception?e){
????????????log.error("setrange命令操作失敗，參數(shù)key：{}，參數(shù)value：{}，參數(shù)offset：{}",?key,?value,?offset,e);
????????}
????????return?null;
????}
????/**
?????*?通過批量的key獲取批量的value
?????*?返回值：一個包含所有給定?key?的值的列表。
?????*?@param?keys
?????*?@return
?????*/
????public?static?List<String>?mget(String...?keys)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.mget(keys);
????????}?catch?(Exception?e){
????????????log.error("mget命令操作失敗，參數(shù)key：{}",?keys.toString(),e);
????????}
????????return?null;
????}
????/**
?????*?批量的設(shè)置key:value,也可以一個
?????*?返回值：總是返回?OK
?????*?@param?keysValues
?????*?@return
?????*/
????public?static?String?mset(String...?keysValues)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.mset(keysValues);
????????}?catch?(Exception?e){
????????????log.error("mset命令操作失敗，參數(shù)key：{}",?keysValues.toString(),e);
????????}
????????return?null;
????}
????/**
?????*?設(shè)置key的值,并返回一個舊值
?????*?返回值：返回給定?key?的舊值，當(dāng)?key?沒有舊值時，即?key?不存在時，返回?nil
?????*?@param?key
?????*?@return
?????*/
????public?static?String?getSet(String?key,?String?value)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.getSet(key,?value);
????????}?catch?(Exception?e){
????????????log.error("getSet命令操作失敗，參數(shù)key：{}，參數(shù)value：{}",?key,?value,e);
????????}
????????return?null;
????}
????/**
?????*?通過下標(biāo)和?key?獲取指定下標(biāo)位置的?value
?????*?返回值：截取得到的子字符串
?????*?@param?key
?????*?@return
?????*/
????public?static?String?getrange(String?key,?int?startOffset,?int?endOffset)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.getrange(key,?startOffset,?endOffset);
????????}?catch?(Exception?e){
????????????log.error("getrange命令操作失敗，參數(shù)key：{}，參數(shù)startOffset：{}，參數(shù)offset：{}",?key,?startOffset,?endOffset,e);
????????}
????????return?null;
????}
????/**
?????*?通過key?對value進(jìn)行加值+1操作,當(dāng)value不是int類型時會返回錯誤,當(dāng)key不存在是則value為1
?????*?返回值：執(zhí)行INCR命令之后?key?的值
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?incr(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.incr(key);
????????}?catch?(Exception?e){
????????????log.error("incr命令操作失敗，參數(shù)key：{}",?key,?e);
????????}
????????return?0L;
????}
????/**
?????*?通過key給指定的value加值
?????*?返回值：執(zhí)行INCR命令之后?key?的值
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?incrBy(String?key,?long?increment)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.incrBy(key,?increment);
????????}?catch?(Exception?e){
????????????log.error("incrBy命令操作失敗，參數(shù)key：{}，參數(shù)increment：{}",?key,?increment,e);
????????}
????????return?0L;
????}
????/**
?????*?對key的值做減減操作
?????*?返回值：執(zhí)行INCR命令之后?key?的值
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?decr(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.decr(key);
????????}?catch?(Exception?e){
????????????log.error("decr命令操作失敗，參數(shù)key：{}",?key,?e);
????????}
????????return?0L;
????}
????/**
?????*?對key的值做減減操作,減去指定的值
?????*?返回值：執(zhí)行INCR命令之后?key?的值
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?decrBy(String?key,?long?decrement)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.decrBy(key,?decrement);
????????}?catch?(Exception?e){
????????????log.error("decrBy命令操作失敗，參數(shù)key：{}，參數(shù)decrement：{}",?key,?decrement,e);
????????}
????????return?0L;
????}
????/**
?????*?通過key獲取value值的長度
?????*?返回值：value值的長度
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?strlen(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.strlen(key);
????????}?catch?(Exception?e){
????????????log.error("strlen命令操作失敗，參數(shù)key：{}",?key,?e);
????????}
????????return?0L;
????}
}
2.5、哈希常用 API 操作
public?class?RedisClientUtil?{
????private?static?final?Logger?log?=?LoggerFactory.getLogger(RedisClientUtil.class);
????/**
?????*?通過key?和?field?獲取指定的?value
?????*?返回值：對應(yīng)的value值
?????*?@param?key
?????*?@return
?????*/
????public?static?String?hget(String?key,?String?field)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.hget(key,?field);
????????}?catch?(Exception?e){
????????????log.error("hget命令操作失敗，參數(shù)key：{}，參數(shù)field：{}",?key,?field,e);
????????}
????????return?null;
????}
????/**
?????*?通過key給field設(shè)置指定的值,如果key不存在,則先創(chuàng)建
?????*?返回值：如果字段是哈希表中的一個新建字段，并且值設(shè)置成功，返回?1?;如果哈希表中域字段已經(jīng)存在且舊值已被新值覆蓋，返回?0?。
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?hset(String?key,?String?field,?String?value)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.hset(key,?field,?value);
????????}?catch?(Exception?e){
????????????log.error("hset命令操作失敗，參數(shù)key：{}，參數(shù)field：{}，參數(shù)value：{}",?key,?field,?value,e);
????????}
????????return?0L;
????}
????/**
?????*?通過key和field判斷是否有指定的value存在
?????*?返回值：true/false
?????*?@param?key
?????*?@return
?????*/
????public?static?Boolean?hexists(String?key,?String?field)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.hexists(key,?field);
????????}?catch?(Exception?e){
????????????log.error("hexists命令操作失敗，參數(shù)key：{}，參數(shù)field：{}",?key,?field,e);
????????}
????????return?false;
????}
????/**
?????*?通過key返回field的數(shù)量
?????*?返回值：field的數(shù)量
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?hlen(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.hlen(key);
????????}?catch?(Exception?e){
????????????log.error("hlen命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?0L;
????}
????/**
?????*?通過key?刪除指定的?field
?????*?返回值：刪除的數(shù)量
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?hdel(String?key,?String...?fields)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.hdel(key,?fields);
????????}?catch?(Exception?e){
????????????log.error("hdel命令操作失敗，參數(shù)key：{}，參數(shù)fields：{}",?key,?fields.toString(),e);
????????}
????????return?0L;
????}
????/**
?????*?通過key返回所有的field
?????*?返回值：field集合
?????*?@param?key
?????*?@return
?????*/
????public?static?Set<String>?hkeys(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.hkeys(key);
????????}?catch?(Exception?e){
????????????log.error("hkeys命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?null;
????}
????/**
?????*?通過key獲取所有的field和value
?????*?返回值：map對象
?????*?@param?key
?????*?@return
?????*/
????public?static?Map<String,?String>?hgetAll(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.hgetAll(key);
????????}?catch?(Exception?e){
????????????log.error("hgetAll命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?null;
????}
}
2.6、列表常用 API 操作
public?class?RedisClientUtil?{
????private?static?final?Logger?log?=?LoggerFactory.getLogger(RedisClientUtil.class);
????/**
?????*?過key向list頭部添加字符串
?????*?返回值：執(zhí)行?LPUSH?命令后，列表的長度
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?lpush(String?key,?String...?strs)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.lpush(key,?strs);
????????}?catch?(Exception?e){
????????????log.error("lpush命令操作失敗，參數(shù)key：{}，參數(shù)strs：{}",?key,?strs.toString(),e);
????????}
????????return?null;
????}
????/**
?????*?通過key向list尾部添加字符串
?????*?返回值：執(zhí)行?RPUSH?命令后，列表的長度
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?rpush(String?key,?String...?strs)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.rpush(key,?strs);
????????}?catch?(Exception?e){
????????????log.error("rpush命令操作失敗，參數(shù)key：{}，參數(shù)strs：{}",?key,?strs.toString(),e);
????????}
????????return?null;
????}
????/**
?????*?通過key設(shè)置list指定下標(biāo)位置的value?如果下標(biāo)超過list里面value的個數(shù)則報(bào)錯
?????*?返回值：操作成功返回?ok?，否則返回錯誤信息
?????*?@param?key
?????*?@return
?????*/
????public?static?String?lset(String?key,?Long?index,?String?value)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.lset(key,?index,?value);
????????}?catch?(Exception?e){
????????????log.error("lset命令操作失敗，參數(shù)key：{}，參數(shù)index：{}，參數(shù)value：{}",?key,?index,?value,e);
????????}
????????return?null;
????}
????/**
?????*?通過key從對應(yīng)的list中刪除指定的count個?和?value相同的元素
?????*?返回值：返回被刪除的個數(shù)
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?lrem(String?key,?long?count,?String?value)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.lrem(key,?count,?value);
????????}?catch?(Exception?e){
????????????log.error("lrem命令操作失敗，參數(shù)key：{}，參數(shù)count：{}，參數(shù)value：{}",?key,?count,?value,e);
????????}
????????return?null;
????}
????/**
?????*?通過key保留list中從strat下標(biāo)開始到end下標(biāo)結(jié)束的value值
?????*?返回值：操作成功返回?ok?，否則返回錯誤信息
?????*?@param?key
?????*?@return
?????*/
????public?static?String?ltrim(String?key,?long?start,?long?end)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.ltrim(key,?start,?end);
????????}?catch?(Exception?e){
????????????log.error("ltrim命令操作失敗，參數(shù)key：{}，參數(shù)start：{}，參數(shù)end：{}",?key,?start,?end,e);
????????}
????????return?null;
????}
????/**
?????*?通過key從list的頭部刪除一個value,并返回該value
?????*?返回值：value值
?????*?@param?key
?????*?@return
?????*/
????public?static?String?lpop(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.lpop(key);
????????}?catch?(Exception?e){
????????????log.error("lpop命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?null;
????}
????/**
?????*?通過key從list尾部刪除一個value,并返回該元素
?????*?返回值：value值
?????*?@param?key
?????*?@return
?????*/
????public?static?String?rpop(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.rpop(key);
????????}?catch?(Exception?e){
????????????log.error("rpop命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?null;
????}
????/**
?????*?通過key獲取list中指定下標(biāo)位置的value
?????*?返回值：value值
?????*?@param?key
?????*?@return
?????*/
????public?static?String?lindex(String?key,?long?index){
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.lindex(key,?index);
????????}?catch?(Exception?e){
????????????log.error("lindex命令操作失敗，參數(shù)key：{}，參數(shù)index：{}",?key,?index,e);
????????}
????????return?null;
????}
????/**
?????*?通過key返回list的長度
?????*?返回值：value值
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?llen(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.llen(key);
????????}?catch?(Exception?e){
????????????log.error("llen命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?null;
????}
????/**
?????*?通過key獲取list指定下標(biāo)位置的value?如果start?為?0?end?為?-1?則返回全部的list中的value
?????*?返回值：value值
?????*?@param?key
?????*?@return
?????*/
????public?static?List<String>?lrange(String?key,?long?start,?long?end)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.lrange(key,?start,?end);
????????}?catch?(Exception?e){
????????????log.error("lrange命令操作失敗，參數(shù)key：{}，參數(shù)start：{}，參數(shù)end：{}",?key,?start,?end,e);
????????}
????????return?null;
????}
}
2.7、集合常用 API 操作
public?class?RedisClientUtil?{
????private?static?final?Logger?log?=?LoggerFactory.getLogger(RedisClientUtil.class);
????/**
?????*?通過key向指定的set中添加value
?????*?返回值：添加成功的個數(shù)
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?sadd(String?key,?String...?members)??{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.sadd(key,?members);
????????}?catch?(Exception?e){
????????????log.error("sadd命令操作失敗，參數(shù)key：{}，參數(shù)members：{}",?key,?members.toString(),e);
????????}
????????return?null;
????}
????/**
?????*?通過key刪除set中對應(yīng)的value值
?????*?返回值：刪除成功的個數(shù)
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?srem(String?key,?String...?members)??{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.srem(key,?members);
????????}?catch?(Exception?e){
????????????log.error("srem命令操作失敗，參數(shù)key：{}，參數(shù)members：{}",?key,?members.toString(),e);
????????}
????????return?null;
????}
????/**
?????*?通過key獲取set中value的個數(shù)
?????*?返回值：value的個數(shù)
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?scard(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.scard(key);
????????}?catch?(Exception?e){
????????????log.error("scard命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?0L;
????}
????/**
?????*?通過key判斷value是否是set中的元素
?????*?返回值：true/false
?????*?@param?key
?????*?@return
?????*/
????public?static?Boolean?sismember(String?key,?String?member)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.sismember(key,?member);
????????}?catch?(Exception?e){
????????????log.error("sismember命令操作失敗，參數(shù)key：{}，參數(shù)member：{}",?key,?member,e);
????????}
????????return?false;
????}
????/**
?????*?通過key獲取set中所有的value
?????*?返回值：所有的value
?????*?@param?key
?????*?@return
?????*/
????public?static?Set<String>?smembers(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.smembers(key);
????????}?catch?(Exception?e){
????????????log.error("smembers命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?null;
????}
}
2.8、有序集合常用 API 操作
public?class?RedisClientUtil?{
????private?static?final?Logger?log?=?LoggerFactory.getLogger(RedisClientUtil.class);
????/**
?????*?通過key向zset中添加value,score,其中score就是用來排序的?如果該value已經(jīng)存在則根據(jù)score更新元素
?????*?返回值：被成功添加的新成員的數(shù)量，不包括那些被更新的、已經(jīng)存在的成員
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?zadd(String?key,?double?score,?String?member)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.zadd(key,?score,?member);
????????}?catch?(Exception?e){
????????????log.error("zadd命令操作失敗，參數(shù)key：{}，參數(shù)score：{}，參數(shù)member：{}",?key,?score,?member,e);
????????}
????????return?null;
????}
????/**
?????*?通過key刪除在zset中指定的value
?????*?返回值：刪除個數(shù)
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?zrem(String?key,?String...?members)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.zrem(key,?members);
????????}?catch?(Exception?e){
????????????log.error("zrem命令操作失敗，參數(shù)key：{}，參數(shù)members：{}",?key,?members.toString(),e);
????????}
????????return?null;
????}
????/**
?????*?通過key增加該zset中value的score的值
?????*?返回值：member?成員的新分?jǐn)?shù)值
?????*?@param?key
?????*?@return
?????*/
????public?static?Double?zincrby(String?key,?double?score,?String?member)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.zincrby(key,?score,?member);
????????}?catch?(Exception?e){
????????????log.error("zincrby命令操作失敗，參數(shù)key：{}，參數(shù)score：{}，參數(shù)member：{}",?key,?score,?member,e);
????????}
????????return?null;
????}
????/**
?????*?通過key返回zset中value的排名?下標(biāo)從小到大排序
?????*?返回值：返回?member?的排名
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?zrank(String?key,?String?member)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.zrank(key,?member);
????????}?catch?(Exception?e){
????????????log.error("zrank命令操作失敗，參數(shù)key：{}，參數(shù)member：{}",?key,?member,e);
????????}
????????return?null;
????}
????/**
?????*?通過key將獲取score從start到end中zset的value?socre從大到小排序?當(dāng)start為0?end為-1時返回全部
?????*?返回值：返回?member?集合
?????*?@param?key
?????*?@return
?????*/
????public?static?Set<String>?zrevrange(String?key,?long?start,?long?end)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.zrevrange(key,?start,?end);
????????}?catch?(Exception?e){
????????????log.error("zrevrange命令操作失敗，參數(shù)key：{}，參數(shù)start：{}，參數(shù)end：{}",?key,?start,?end,e);
????????}
????????return?null;
????}
????/**
?????*?返回指定區(qū)間內(nèi)zset中value的數(shù)量
?????*?返回值：返回?member?集合
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?zcount(String?key,?String?min,?String?max)??{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.zcount(key,?min,?max);
????????}?catch?(Exception?e){
????????????log.error("zcount命令操作失敗，參數(shù)key：{}，參數(shù)min：{}，參數(shù)max：{}",?key,?min,?max,e);
????????}
????????return?null;
????}
????/**
?????*?通過key返回zset中的value個數(shù)
?????*?返回值：返回?member?集合
?????*?@param?key
?????*?@return
?????*/
????public?static?Long?zcard(String?key)??{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.zcard(key);
????????}?catch?(Exception?e){
????????????log.error("zcard命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?null;
????}
????/**
?????*?返回滿足pattern表達(dá)式的所有key?keys(*)?返回所有的key
?????*?返回值：返回?key?集合
?????*?@param?pattern
?????*?@return
?????*/
????public?static?Set<String>?keys(String?pattern)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.keys(pattern);
????????}?catch?(Exception?e){
????????????log.error("keys命令操作失敗，參數(shù)pattern：{}",?pattern,e);
????????}
????????return?null;
????}
????/**
?????*?通過key判斷值得類型
?????*?返回值：值的類型
?????*?@param?key
?????*?@return
?????*/
????public?static?String?type(String?key)?{
????????try?(Jedis?jedis?=?jedisPool.getResource())?{
????????????return?jedis.type(key);
????????}?catch?(Exception?e){
????????????log.error("type命令操作失敗，參數(shù)key：{}",?key,e);
????????}
????????return?null;
????}
}
三、集群配置
在實(shí)際的項(xiàng)目生產(chǎn)環(huán)境中，redis 通常不是以單臺服務(wù)實(shí)例來運(yùn)行的，因?yàn)橐坏┓?wù)器掛了，可能所有的下游服務(wù)都會受到影響，因此為了保障單臺服務(wù)器即使出現(xiàn)故障也能運(yùn)行，通常運(yùn)維組會搭建集群環(huán)境，來保證服務(wù)高可用。
搭建的方式有兩種，哨兵模式和 Cluster 模式。
- 哨兵模式：對redis服務(wù)器進(jìn)行監(jiān)控，如果有宕機(jī)的，就從備機(jī)里面選一個出來作為主機(jī)，實(shí)現(xiàn)自動切換
- Cluster 模式：將數(shù)據(jù)進(jìn)行分片存儲，避免全部節(jié)點(diǎn)數(shù)據(jù)都一樣，浪費(fèi)空間
3.1、哨兵模式
哨兵模式簡單的說，就是一臺主機(jī)，一臺備機(jī)，外加一臺監(jiān)控服務(wù)，當(dāng)監(jiān)控服務(wù)觀測到主機(jī)已經(jīng)宕機(jī)，就會將備用機(jī)切換成主機(jī)，以便繼續(xù)提供服務(wù)。
public?class?RedisPoolUtils?{
????private?static?Jedis?jedis;
????private?static?JedisSentinelPool?jedisSentinelPool;
????static{
????????try?{
????????????JedisPoolConfig?config?=?new?JedisPoolConfig();
????????????//最大空閑連接數(shù),?默認(rèn)8個
????????????config.setMaxIdle(8);
????????????//最大連接數(shù),?默認(rèn)8個
????????????config.setMaxTotal(8);
????????????//最小空閑連接數(shù),?默認(rèn)0
????????????config.setMinIdle(0);
????????????//獲取連接時的最大等待毫秒數(shù)(如果設(shè)置為阻塞時BlockWhenExhausted),如果超時就拋異常,?小于零:阻塞不確定的時間,??默認(rèn)-1
????????????config.setMaxWaitMillis(3000);
????????????//在獲取連接的時候檢查有效性,表示取出的redis對象可用,?默認(rèn)false
????????????config.setTestOnBorrow(true);
????????????//redis服務(wù)器列表
????????????Set<String>?sentinels?=?new?HashSet<>();
????????????sentinels.add(new?HostAndPort("192.168.43.212",?26379).toString());
????????????sentinels.add(new?HostAndPort("192.168.43.213",?26379).toString());
????????????sentinels.add(new?HostAndPort("192.168.43.214",?26379).toString());
????????????//初始化連接池
????????????jedisSentinelPool?=?new?JedisSentinelPool("mymaster",?sentinels,?config,?"111111");
????????????//?從池中獲取一個Jedis對象
????????????jedis?=?jedisSentinelPool.getResource();
????????}?catch?(Exception?e)?{
????????????e.printStackTrace();
????????}
????}
????
}
3.2、集群模式
為了保證高可用，redis-cluster集群通常會引入主從復(fù)制模型，一個主節(jié)點(diǎn)對應(yīng)一個或者多個從節(jié)點(diǎn)，當(dāng)主節(jié)點(diǎn)宕機(jī)的時候，就會啟用從節(jié)點(diǎn)。
public?class?RedisPoolUtils?{
????static{
????????try?{
????????????JedisPoolConfig?config?=?new?JedisPoolConfig();
????????????//最大空閑連接數(shù),?默認(rèn)8個
????????????config.setMaxIdle(8);
????????????//最大連接數(shù),?默認(rèn)8個
????????????config.setMaxTotal(8);
????????????//最小空閑連接數(shù),?默認(rèn)0
????????????config.setMinIdle(0);
????????????//獲取連接時的最大等待毫秒數(shù)(如果設(shè)置為阻塞時BlockWhenExhausted),如果超時就拋異常,?小于零:阻塞不確定的時間,??默認(rèn)-1
????????????config.setMaxWaitMillis(3000);
????????????//在獲取連接的時候檢查有效性,表示取出的redis對象可用,?默認(rèn)false
????????????config.setTestOnBorrow(true);
????????????Set<HostAndPort>?nodes?=?new?HashSet<>();
????????????nodes.add(new?HostAndPort("192.168.43.212",?26379));
????????????nodes.add(new?HostAndPort("192.168.43.213",?26379));
????????????nodes.add(new?HostAndPort("192.168.43.214",?26379));
????????????JedisCluster?jedisCluster?=?new?JedisCluster(nodes,?config);
????????????jedisCluster.set("key",?"hello?world");
????????????jedisCluster.close();
????????}?catch?(Exception?e)?{
????????????e.printStackTrace();
????????}
????}
}
四、小結(jié)
jedis客戶端是目前使用最廣泛的一款 java 客戶端，也是老牌的 Redis 的 Java 實(shí)現(xiàn)客戶端。
優(yōu)點(diǎn)很突出：
- 比較全面的提供了 Redis 的操作特性，也就是說你能用 redis 命令操作的，Jedis 包都也給你封裝好了，直接使用即可
- 使用廣泛，易上手
當(dāng)然，缺點(diǎn)也有：
- Jedis 客戶端實(shí)例不是線程安全的，需要借助連接池來管理和使用 Jedis
- 使用阻塞的I/O，且其方法調(diào)用都是同步的，程序流需要等到 sockets 處理完 I/O 才能執(zhí)行，不支持異步
到此這篇關(guān)于Redis實(shí)戰(zhàn)之Jedis使用技巧詳解的文章就介紹到這了,更多相關(guān)Redis Jedis內(nèi)容請搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！
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