Redis之Lettuce怎麼使用
- WBOY轉載
- 2023-05-28 21:51:241648瀏覽
一、摘要
Lettuce 是 Redis 的一款高級 Java 用戶端，與 Jedis 並列成為最熱門的客戶端之一，目前已成為 SpringBoot 2.0 版本預設的 redis 用戶端。
相比老牌 Jedis，Lettuce 屬於後起之秀，不僅功能豐富，而且提供了許多新的功能特性，例如非同步操作、響應式程式設計等等，同時還解決了 Jedis 中線程不安全的問題。
二、Lettuce
2.1、基本使用
首先，建立一個 maven 項目，引入lettuce-core包，就可以使用了。
<dependency> <groupId>io.lettuce</groupId> <artifactId>lettuce-core</artifactId> <version>5.3.1.RELEASE</version> </dependency>
使用 lettuce 連接 redis，測試是否能正常聯通！
public class LettuceMain {
public static void main(String[] args) {
RedisURI redisUri = RedisURI.builder()
.withHost("127.0.0.1")
.withPort(6379)
.withPassword("111111")
.withTimeout(Duration.of(10, ChronoUnit.SECONDS))
.build();
RedisClient redisClient = RedisClient.create(redisUri);
StatefulRedisConnection<String, String> connection = redisClient.connect();
RedisCommands<String, String> commands = connection.sync();
System.out.println(commands.ping());
connection.close();
redisClient.shutdown();
}
}2.2、同步操作
基本上只要是 Jedis 支援的同步指令操作，Lettuce 都會支援。
下面，我們以同步運算字串為例，Lettuce 的 api 運算如下！
public class LettuceSyncMain {
public static void main(String[] args) {
RedisURI redisUri = RedisURI.builder()
.withHost("127.0.0.1").withPort(6379).withPassword("111111")
.withTimeout(Duration.of(10, ChronoUnit.SECONDS))
.build();
RedisClient redisClient = RedisClient.create(redisUri);
StatefulRedisConnection<String, String> connection = redisClient.connect();
//获取同步操作命令工具
RedisCommands<String, String> commands = connection.sync();
System.out.println("清空数据："+commands.flushdb());
System.out.println("判断某个键是否存在："+commands.exists("username"));
System.out.println("新增<'username','xmr'>的键值对："+commands.set("username", "xmr"));
System.out.println("新增<'password','password'>的键值对："+commands.set("password", "123"));
System.out.println("获取<'password'>键的值："+commands.get("password"));
System.out.println("系统中所有的键如下：" + commands.keys("*"));
System.out.println("删除键password:"+commands.del("password"));
System.out.println("判断键password是否存在："+commands.exists("password"));
System.out.println("设置键username的过期时间为5s:"+commands.expire("username", 5L));
System.out.println("查看键username的剩余生存时间："+commands.ttl("username"));
System.out.println("移除键username的生存时间："+commands.persist("username"));
System.out.println("查看键username的剩余生存时间："+commands.ttl("username"));
System.out.println("查看键username所存储的值的类型："+commands.type("username"));
connection.close();
redisClient.shutdown();
}
}2.3、非同步操作
除此之外，Lettuce 也支援非同步操作，將上面的操作改成非同步處理，結果如下！
public class LettuceASyncMain {
public static void main(String[] args) throws Exception {
RedisURI redisUri = RedisURI.builder()
.withHost("127.0.0.1").withPort(6379).withPassword("111111")
.withTimeout(Duration.of(10, ChronoUnit.SECONDS))
.build();
RedisClient redisClient = RedisClient.create(redisUri);
StatefulRedisConnection<String, String> connection = redisClient.connect();
//获取异步操作命令工具
RedisAsyncCommands<String, String> commands = connection.async();
System.out.println("清空数据："+commands.flushdb().get());
System.out.println("判断某个键是否存在："+commands.exists("username").get());
System.out.println("新增<'username','xmr'>的键值对："+commands.set("username", "xmr").get());
System.out.println("新增<'password','password'>的键值对："+commands.set("password", "123").get());
System.out.println("获取<'password'>键的值："+commands.get("password").get());
System.out.println("系统中所有的键如下：" + commands.keys("*").get());
System.out.println("删除键password:"+commands.del("password").get());
System.out.println("判断键password是否存在："+commands.exists("password").get());
System.out.println("设置键username的过期时间为5s:"+commands.expire("username", 5L).get());
System.out.println("查看键username的剩余生存时间："+commands.ttl("username").get());
System.out.println("移除键username的生存时间："+commands.persist("username").get());
System.out.println("查看键username的剩余生存时间："+commands.ttl("username").get());
System.out.println("查看键username所存储的值的类型："+commands.type("username").get());
connection.close();
redisClient.shutdown();
}
}2.4、響應式編程
Lettuce 除了支援非同步編程以外，還支援響應式編程，Lettuce 引入的響應式編程框架是Project Reactor，如果沒有響應式程式設計經驗可以先自行了解。
響應式程式設計使用案例如下：
public class LettuceMain {
public static void main(String[] args) throws Exception {
RedisURI redisUri = RedisURI.builder()
.withHost("127.0.0.1").withPort(6379).withPassword("111111")
.withTimeout(Duration.of(10, ChronoUnit.SECONDS))
.build();
RedisClient redisClient = RedisClient.create(redisUri);
StatefulRedisConnection<String, String> connection = redisClient.connect();
//获取响应式API操作命令工具
RedisReactiveCommands<String, String> commands = connection.reactive();
Mono<String> setc = commands.set("name", "mayun");
System.out.println(setc.block());
Mono<String> getc = commands.get("name");
getc.subscribe(System.out::println);
Flux<String> keys = commands.keys("*");
keys.subscribe(System.out::println);
//开启一个事务，先把count设置为1，再将count自增1
commands.multi().doOnSuccess(r -> {
commands.set("count", "1").doOnNext(value -> System.out.println("count1：" + value)).subscribe();
commands.incr("count").doOnNext(value -> System.out.println("count2：" + value)).subscribe();
}).flatMap(s -> commands.exec())
.doOnNext(transactionResult -> System.out.println("transactionResult：" + transactionResult.wasDiscarded())).subscribe();
Thread.sleep(1000 * 5);
connection.close();
redisClient.shutdown();
}
}2.5、發布和訂閱
Lettuce 也支援redis 的訊息發布和訂閱，具體實作案例如下：
public class LettuceReactiveMain1 {
public static void main(String[] args) throws Exception {
RedisURI redisUri = RedisURI.builder()
.withHost("127.0.0.1").withPort(6379).withPassword("111111")
.withTimeout(Duration.of(10, ChronoUnit.SECONDS))
.build();
RedisClient redisClient = RedisClient.create(redisUri);
//获取发布订阅操作命令工具
StatefulRedisPubSubConnection<String, String> pubsubConn = redisClient.connectPubSub();
pubsubConn.addListener(new RedisPubSubListener<String, String>() {
@Override
public void unsubscribed(String channel, long count) {
System.out.println("[unsubscribed]" + channel);
}
@Override
public void subscribed(String channel, long count) {
System.out.println("[subscribed]" + channel);
}
@Override
public void punsubscribed(String pattern, long count) {
System.out.println("[punsubscribed]" + pattern);
}
@Override
public void psubscribed(String pattern, long count) {
System.out.println("[psubscribed]" + pattern);
}
@Override
public void message(String pattern, String channel, String message) {
System.out.println("[message]" + pattern + " -> " + channel + " -> " + message);
}
@Override
public void message(String channel, String message) {
System.out.println("[message]" + channel + " -> " + message);
}
});
RedisPubSubAsyncCommands<String, String> pubsubCmd = pubsubConn.async();
pubsubCmd.psubscribe("CH");
pubsubCmd.psubscribe("CH2");
pubsubCmd.unsubscribe("CH");
Thread.sleep(100 * 5);
pubsubConn.close();
redisClient.shutdown();
}
} 2.6、客戶端資源與參數配置
Lettuce 用戶端的通訊框架整合了Netty 的非阻塞IO 操作，客戶端資源的設定與Lettuce 的效能、並發和事件處理緊密相關，如果不是特別熟悉客戶端參數配置，不建議在沒有經驗的前提下憑直覺修改預設值，保持預設配置就行。
非叢集環境下，具體的設定案例如下：
public class LettuceMain {
public static void main(String[] args) throws Exception {
ClientResources resources = DefaultClientResources.builder()
.ioThreadPoolSize(4) //I/O线程数
.computationThreadPoolSize(4) //任务线程数
.build();
RedisURI redisUri = RedisURI.builder()
.withHost("127.0.0.1").withPort(6379).withPassword("111111")
.withTimeout(Duration.of(10, ChronoUnit.SECONDS))
.build();
ClientOptions options = ClientOptions.builder()
.autoReconnect(true)//是否自动重连
.pingBeforeActivateConnection(true)//连接激活之前是否执行PING命令
.build();
RedisClient client = RedisClient.create(resources, redisUri);
client.setOptions(options);
StatefulRedisConnection<String, String> connection = client.connect();
RedisCommands<String, String> commands = connection.sync();
commands.set("name", "关羽");
System.out.println(commands.get("name"));
connection.close();
client.shutdown();
resources.shutdown();
}
}叢集環境下，具體的設定案例如下：
public class LettuceMain {
public static void main(String[] args) throws Exception {
ClientResources resources = DefaultClientResources.builder()
.ioThreadPoolSize(4) //I/O线程数
.computationThreadPoolSize(4) //任务线程数
.build();
RedisURI redisUri = RedisURI.builder()
.withHost("127.0.0.1").withPort(6379).withPassword("111111")
.withTimeout(Duration.of(10, ChronoUnit.SECONDS))
.build();
ClusterClientOptions options = ClusterClientOptions.builder()
.autoReconnect(true)//是否自动重连
.pingBeforeActivateConnection(true)//连接激活之前是否执行PING命令
.validateClusterNodeMembership(true)//是否校验集群节点的成员关系
.build();
RedisClusterClient client = RedisClusterClient.create(resources, redisUri);
client.setOptions(options);
StatefulRedisClusterConnection<String, String> connection = client.connect();
RedisAdvancedClusterCommands<String, String> commands = connection.sync();
commands.set("name", "张飞");
System.out.println(commands.get("name"));
connection.close();
client.shutdown();
resources.shutdown();
}
}2.7、執行緒池配置
Lettuce 連接設計的時候，就是線程安全的，所以一個連接可以被多個線程共享，同時lettuce 連接預設是自動重連的，使用單連接基本上可以滿足業務需求，大多數情況下不需要配置連接池，多重連線不會為操作帶來效能上的提升。
但在某些特殊場景下，例如事物操作，使用連線池會是比較好的方案，那麼如何配置執行緒池呢？
public class LettuceMain {
public static void main(String[] args) throws Exception {
RedisURI redisUri = RedisURI.builder()
.withHost("127.0.0.1")
.withPort(6379)
.withPassword("111111")
.withTimeout(Duration.of(10, ChronoUnit.SECONDS))
.build();
RedisClient client = RedisClient.create(redisUri);
//连接池配置
GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
poolConfig.setMaxIdle(2);
GenericObjectPool<StatefulRedisConnection<String, String>> pool = ConnectionPoolSupport.createGenericObjectPool(client::connect, poolConfig);
StatefulRedisConnection<String, String> connection = pool.borrowObject();
RedisCommands<String, String> commands = connection.sync();
commands.set("name", "张飞");
System.out.println(commands.get("name"));
connection.close();
pool.close();
client.shutdown();
}
}2.8、主從模式配置
redis 一般採用主從複製模式，搭建高可用的架構，簡單的說就一個主節點，多個從節點，自動從主節點同步最新資料。
Lettuce 支援自動發現主從模式下的節點信息，然後保存到本地，具體配置如下：
public class LettuceMain {
public static void main(String[] args) throws Exception {
//这里只需要配置一个节点的连接信息，不一定需要是主节点的信息，从节点也可以;可以自动发现主从节点
RedisURI uri = RedisURI.builder().withHost("192.168.31.111").withPort(6379).withPassword("123456").build();
RedisClient client = RedisClient.create(uri);
StatefulRedisMasterReplicaConnection<String, String> connection = MasterReplica.connect(client, StringCodec.UTF8, uri);
//从节点读取数据
connection.setReadFrom(ReadFrom.REPLICA);
RedisCommands<String, String> commands = connection.sync();
commands.set("name", "张飞");
System.out.println(commands.get("name"));
connection.close();
client.shutdown();
}
}當然我們也可以手動指定集群節點來加載，具體配置如下：
public class LettuceMain {
public static void main(String[] args) throws Exception {
//集群节点
List<RedisURI> uris = new ArrayList();
uris.add(RedisURI.builder().withHost("192.168.31.111").withPort(6379).withPassword("111111").build());
uris.add(RedisURI.builder().withHost("192.168.31.112").withPort(6379).withPassword("111111").build());
uris.add(RedisURI.builder().withHost("192.168.31.113").withPort(6379).withPassword("111111").build());
RedisClient client = RedisClient.create();
StatefulRedisMasterReplicaConnection<String, String> connection = MasterReplica.connect(client, StringCodec.UTF8, uris);
//从节点读取数据
connection.setReadFrom(ReadFrom.REPLICA);
RedisCommands<String, String> commands = connection.sync();
commands.set("name", "张飞");
System.out.println(commands.get("name"));
connection.close();
client.shutdown();
}
}2.9、哨兵模式配置
哨兵模式，也是redis 實現服務高可用的一大亮點，具體配置實現如下：
public class LettuceMain {
public static void main(String[] args) throws Exception {
//集群节点
List<RedisURI> uris = new ArrayList();
uris.add(RedisURI.builder().withSentinel("192.168.31.111", 26379).withSentinelMasterId("mymaster").withPassword("123456").build());
uris.add(RedisURI.builder().withSentinel("192.168.31.112", 26379).withSentinelMasterId("mymaster").withPassword("123456").build());
uris.add(RedisURI.builder().withSentinel("192.168.31.113", 26379).withSentinelMasterId("mymaster").withPassword("123456").build());
RedisClient client = RedisClient.create();
StatefulRedisMasterReplicaConnection<String, String> connection = MasterReplica.connect(client, StringCodec.UTF8, uris);
//从节点读取数据
connection.setReadFrom(ReadFrom.REPLICA);
RedisCommands<String, String> commands = connection.sync();
commands.set("name", "赵云");
System.out.println(commands.get("name"));
connection.close();
client.shutdown();
}
}2.10、Cluster 集群模式配置
Cluster 叢集模式，是之後推出的一種高可用的架構模型，主要是採用分片方式來儲存數據，具體配置如下：
public class LettuceReactiveMain4 {
public static void main(String[] args) throws Exception {
Set<RedisURI> uris = new HashSet<>();
uris.add(RedisURI.builder().withHost("192.168.31.111").withPort(7000).withPassword("123456").build());
uris.add(RedisURI.builder().withHost("192.168.31.112").withPort(7000).withPassword("123456").build());
uris.add(RedisURI.builder().withHost("192.168.31.113").withPort(7000).withPassword("123456").build());
uris.add(RedisURI.builder().withHost("192.168.31.114").withPort(7000).withPassword("123456").build());
uris.add(RedisURI.builder().withHost("192.168.31.115").withPort(7000).withPassword("123456").build());
uris.add(RedisURI.builder().withHost("192.168.31.116").withPort(7001).withPassword("123456").build());
RedisClusterClient client = RedisClusterClient.create(uris);
StatefulRedisClusterConnection<String, String> connection = client.connect();
RedisAdvancedClusterCommands<String, String> commands = connection.sync();
commands.set("name", "关羽");
System.out.println(commands.get("name"));
//选择从节点,只读
NodeSelection<String, String> replicas = commands.replicas();
NodeSelectionCommands<String, String> nodeSelectionCommands = replicas.commands();
Executions<List<String>> keys = nodeSelectionCommands.keys("*");
keys.forEach(key -> System.out.println(key));
connection.close();
client.shutdown();
}
}以上是Redis之Lettuce怎麼使用的詳細內容。更多資訊請關注PHP中文網其他相關文章！
陳述：
本文轉載於：yisu.com。如有侵權，請聯絡admin@php.cn刪除