Redisson 是一种基于 Redis 的 Java 驻留集群的分布式对象和服务库，可以为我们提供丰富的分布式锁和线程安全集合的实现。在 Spring Boot 应用程序中使用 Redisson 可以方便地实现分布式应用程序的某些方面，例如分布式锁、分布式集合、分布式事件发布和订阅等。本篇是一个使用 Redisson 实现分布式锁的详细示例，在这个示例中，我们定义了DistributedLock注解，它可以标注在方法上，配合DistributedLockAspect切面以及IDistributedLock分布式锁封装的接口，来实现redisson 分布式锁的 API 调用。

Spring Boot 集成 Redisson

 1、在 pom.xml 文件中添加 Redisson 的相关依赖

<dependency><groupId>org.redisson</groupId><artifactId>redisson-spring-boot-starter</artifactId><version>3.16.1</version>
</dependency>

2、在 application.yml 中配置 Redisson单机模式 的连接信息和相关参数

spring:redis:host: localhostport: 6379password: null
redisson:codec: org.redisson.codec.JsonJacksonCodecthreads: 4netty:threads: 4single-server-config:address: "redis://localhost:6379"password: nulldatabase: 0

3、Redission还支持主从、集群、哨兵配置

//主从模式
spring:redis:sentinel:master: my-masternodes: localhost:26379,localhost:26389password: your_password
redisson:master-slave-config:master-address: "redis://localhost:6379"slave-addresses: "redis://localhost:6380,redis://localhost:6381"password: ${spring.redis.password}// 集群模式
spring:redis:cluster:nodes: localhost:6379,localhost:6380,localhost:6381,localhost:6382,localhost:6383,localhost:6384password: your_password
redisson:cluster-config:node-addresses: "redis://localhost:6379,redis://localhost:6380,redis://localhost:6381,redis://localhost:6382,redis://localhost:6383,redis://localhost:6384"password: ${spring.redis.password}// 哨兵模式
spring:redis:sentinel:master: my-masternodes: localhost:26379,localhost:26389password: your_password
redisson:sentinel-config:master-name: my-mastersentinel-addresses: "redis://localhost:26379,redis://localhost:26380,redis://localhost:26381"password: ${spring.redis.password}

 本地封装Redisson 分布式锁

1、定义IDistributedLock分布式锁接口

public interface IDistributedLock {/*** 获取锁，默认30秒失效，失败一直等待直到获取锁** @param key 锁的key* @return 锁对象*/ILock lock(String key);/*** 获取锁,失败一直等待直到获取锁** @param key      锁的key* @param lockTime 加锁的时间，超过这个时间后锁便自动解锁； 如果lockTime为-1，则保持锁定直到显式解锁* @param unit     {@code lockTime} 参数的时间单位* @param fair     是否公平锁* @return 锁对象*/ILock lock(String key, long lockTime, TimeUnit unit, boolean fair);/*** 尝试获取锁，30秒获取不到超时异常，锁默认30秒失效** @param key     锁的key* @param tryTime 获取锁的最大尝试时间* @return* @throws Exception*/ILock tryLock(String key, long tryTime) throws Exception;/*** 尝试获取锁，获取不到超时异常** @param key      锁的key* @param tryTime  获取锁的最大尝试时间* @param lockTime 加锁的时间* @param unit     {@code tryTime @code lockTime} 参数的时间单位* @param fair     是否公平锁* @return* @throws Exception*/ILock tryLock(String key, long tryTime, long lockTime, TimeUnit unit, boolean fair) throws Exception;/*** 解锁** @param lock* @throws Exception*/void unLock(Object lock);/*** 释放锁** @param lock* @throws Exception*/default void unLock(ILock lock) {if (lock != null) {unLock(lock.getLock());}}}

2、IDistributedLock实现类

@Slf4j
@Component
public class RedissonDistributedLock implements IDistributedLock {@Resourceprivate RedissonClient redissonClient;/*** 统一前缀*/@Value("${redisson.lock.prefix:bi:distributed:lock}")private String prefix;@Overridepublic ILock lock(String key) {return this.lock(key, 0L, TimeUnit.SECONDS, false);}@Overridepublic ILock lock(String key, long lockTime, TimeUnit unit, boolean fair) {RLock lock = getLock(key, fair);// 获取锁,失败一直等待,直到获取锁,不支持自动续期if (lockTime > 0L) {lock.lock(lockTime, unit);} else {// 具有Watch Dog 自动延期机制 默认续30s 每隔30/3=10 秒续到30slock.lock();}return new ILock(lock, this);}@Overridepublic ILock tryLock(String key, long tryTime) throws Exception {return this.tryLock(key, tryTime, 0L, TimeUnit.SECONDS, false);}@Overridepublic ILock tryLock(String key, long tryTime, long lockTime, TimeUnit unit, boolean fair)throws Exception {RLock lock = getLock(key, fair);boolean lockAcquired;// 尝试获取锁，获取不到超时异常,不支持自动续期if (lockTime > 0L) {lockAcquired = lock.tryLock(tryTime, lockTime, unit);} else {// 具有Watch Dog 自动延期机制 默认续30s 每隔30/3=10 秒续到30slockAcquired = lock.tryLock(tryTime, unit);}if (lockAcquired) {return new ILock(lock, this);}return null;}/*** 获取锁** @param key* @param fair* @return*/private RLock getLock(String key, boolean fair) {RLock lock;String lockKey = prefix + ":" + key;if (fair) {// 获取公平锁lock = redissonClient.getFairLock(lockKey);} else {// 获取普通锁lock = redissonClient.getLock(lockKey);}return lock;}@Overridepublic void unLock(Object lock) {if (!(lock instanceof RLock)) {throw new IllegalArgumentException("Invalid lock object");}RLock rLock = (RLock) lock;if (rLock.isLocked()) {try {rLock.unlock();} catch (IllegalMonitorStateException e) {log.error("释放分布式锁异常", e);}}}
}

 3、定义ILock锁对象

import lombok.AllArgsConstructor;
import lombok.Getter;import java.util.Objects;/*** <p>* RedissonLock 包装的锁对象 实现AutoCloseable接口，在java7的try(with resource)语法，不用显示调用close方法* </p>* @since 2023-06-08 16:57*/
@AllArgsConstructor
public class ILock implements AutoCloseable {/*** 持有的锁对象*/@Getterprivate Object lock;/*** 分布式锁接口*/@Getterprivate IDistributedLock distributedLock;@Overridepublic void close() throws Exception {if(Objects.nonNull(lock)){distributedLock.unLock(lock);}}
}

4、注入IDistributedLock接口使用示例

// 定义接口
public interface IProductSkuSupplierMeasureService {/*** 保存SKU供应商供货信息** @param dto* @return*Boolean saveSupplierInfo(ProductSkuSupplierInfoDTO dto);/*** 编辑SKU供应商供货信息** @param dto* @return*/Boolean editSupplierInfo(ProductSkuSupplierInfoDTO dto);
}    

手动释放锁示例 

// 实现类
@Service
public class ProductSkuSupplierMeasureServiceImpl implements IProductSkuSupplierMeasureService {@Resourceprivate IDistributedLock distributedLock;    @Override@Transactional(rollbackFor = Exception.class)public Boolean saveSupplierInfo(ProductSkuSupplierInfoDTO dto) {// 手动释放锁String sku = dto.getSku();ILock lock = null;try {lock = distributedLock.lock(dto.getSku(),10L, TimeUnit.SECONDS, false);// 业务代码} catch (Exception e) {log.error("保存异常", e);throw new BaseException(e.getMessage());} finally {if (Objects.nonNull(lock)) {distributedLock.unLock(lock);}}return Boolean.TRUE;}}

 使用try-with-resources 语法糖自动释放锁

// 实现类
@Service
public class ProductSkuSupplierMeasureServiceImpl implements IProductSkuSupplierMeasureService {@Resourceprivate IDistributedLock distributedLock;    @Override@Transactional(rollbackFor = Exception.class)public Boolean editSupplierInfo(ProductSkuSupplierInfoDTO dto) {String sku = dto.getSku();// try-with-resources 语法糖自动释放锁try(ILock lock = distributedLock.lock(dto.getSku(),10L, TimeUnit.SECONDS, false)) {if(Objects.isNull(lock)){throw new IdempotencyException("Duplicate request for method still in process");}// 业务代码} catch (Exception e) {log.error("异常", e);throw new BaseException(e.getMessage());}return Boolean.TRUE;}
}

5、使用AOP切面实现分布式锁的绑定

  定义DistributedLock注解

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DistributedLock {/*** 保证业务接口的key的唯一性，否则失去了分布式锁的意义 锁key* 支持使用spEl表达式*/String key();/*** 保证业务接口的key的唯一性，否则失去了分布式锁的意义 锁key 前缀*/String keyPrefix() default "";/*** 是否在等待时间内获取锁，如果在等待时间内无法获取到锁，则返回失败*/boolean tryLok() default false;/*** 获取锁的最大尝试时间 ，会尝试tryTime时间获取锁，在该时间内获取成功则返回，否则抛出获取锁超时异常，tryLok=true时，该值必须大于0。**/long tryTime() default 0;/*** 加锁的时间，超过这个时间后锁便自动解锁*/long lockTime() default 30;/*** tryTime 和 lockTime的时间单位*/TimeUnit unit() default TimeUnit.SECONDS;/*** 是否公平锁，false:非公平锁，true:公平锁*/boolean fair() default false;
}

 定义DistributedLockAspect Lock切面

@Aspect
@Slf4j
public class DistributedLockAspect {@Resourceprivate IDistributedLock distributedLock;/*** SpEL表达式解析*/private SpelExpressionParser spelExpressionParser = new SpelExpressionParser();/*** 用于获取方法参数名字*/private DefaultParameterNameDiscoverer nameDiscoverer = new DefaultParameterNameDiscoverer();@Pointcut("@annotation(com.yt.bi.common.redis.distributedlok.annotation.DistributedLock)")public void distributorLock() {}@Around("distributorLock()")public Object around(ProceedingJoinPoint pjp) throws Throwable {// 获取DistributedLockDistributedLock distributedLock = this.getDistributedLock(pjp);// 获取 lockKeyString lockKey = this.getLockKey(pjp, distributedLock);ILock lockObj = null;try {// 加锁，tryLok = true,并且tryTime > 0时，尝试获取锁，获取不到超时异常if (distributedLock.tryLok()) {if(distributedLock.tryTime() <= 0){throw new IdempotencyException("tryTime must be greater than 0");}lockObj = this.distributedLock.tryLock(lockKey, distributedLock.tryTime(), distributedLock.lockTime(), distributedLock.unit(), distributedLock.fair());} else {lockObj = this.distributedLock.lock(lockKey, distributedLock.lockTime(), distributedLock.unit(), distributedLock.fair());}if (Objects.isNull(lockObj)) {throw new IdempotencyException("Duplicate request for method still in process");}return pjp.proceed();} catch (Exception e) {throw e;} finally {// 解锁this.unLock(lockObj);}}/*** @param pjp* @return* @throws NoSuchMethodException*/private DistributedLock getDistributedLock(ProceedingJoinPoint pjp) throws NoSuchMethodException {String methodName = pjp.getSignature().getName();Class clazz = pjp.getTarget().getClass();Class<?>[] par = ((MethodSignature) pjp.getSignature()).getParameterTypes();Method lockMethod = clazz.getMethod(methodName, par);DistributedLock distributedLock = lockMethod.getAnnotation(DistributedLock.class);return distributedLock;}/*** 解锁** @param lockObj*/private void unLock(ILock lockObj) {if (Objects.isNull(lockObj)) {return;}try {this.distributedLock.unLock(lockObj);} catch (Exception e) {log.error("分布式锁解锁异常", e);}}/*** 获取 lockKey** @param pjp* @param distributedLock* @return*/private String getLockKey(ProceedingJoinPoint pjp, DistributedLock distributedLock) {String lockKey = distributedLock.key();String keyPrefix = distributedLock.keyPrefix();if (StringUtils.isBlank(lockKey)) {throw new IdempotencyException("Lok key cannot be empty");}if (lockKey.contains("#")) {this.checkSpEL(lockKey);MethodSignature methodSignature = (MethodSignature) pjp.getSignature();// 获取方法参数值Object[] args = pjp.getArgs();lockKey = getValBySpEL(lockKey, methodSignature, args);}lockKey = StringUtils.isBlank(keyPrefix) ? lockKey : keyPrefix + lockKey;return lockKey;}/*** 解析spEL表达式** @param spEL* @param methodSignature* @param args* @return*/private String getValBySpEL(String spEL, MethodSignature methodSignature, Object[] args) {// 获取方法形参名数组String[] paramNames = nameDiscoverer.getParameterNames(methodSignature.getMethod());if (paramNames == null || paramNames.length < 1) {throw new IdempotencyException("Lok key cannot be empty");}Expression expression = spelExpressionParser.parseExpression(spEL);// spring的表达式上下文对象EvaluationContext context = new StandardEvaluationContext();// 给上下文赋值for (int i = 0; i < args.length; i++) {context.setVariable(paramNames[i], args[i]);}return expression.getValue(context).toString();}/*** SpEL 表达式校验** @param spEL* @return*/private void checkSpEL(String spEL) {try {ExpressionParser parser = new SpelExpressionParser();parser.parseExpression(spEL, new TemplateParserContext());} catch (Exception e) {log.error("spEL表达式解析异常", e);throw new IdempotencyException("Invalid SpEL expression [" + spEL + "]");}}
}

定义分布式锁注解版启动元注解

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import({DistributedLockAspect.class})
public @interface EnableDistributedLock {
}

6、AOP切面实现分布式锁的绑定使用示例

   启动类添加@EnableDistributedLock启用注解支持

@SpringBootApplication
@EnableDistributedLock
public class BiCenterGoodsApplication {public static void main(String[] args) {SpringApplication.run(BiCenterGoodsApplication.class, args);}
}

@DistributedLock标注需要使用分布式锁的方法 

    @ApiOperation("编辑SKU供应商供货信息")@PostMapping("/editSupplierInfo")//@DistributedLock(key = "#dto.sku + '-' + #dto.skuId", lockTime = 10L, keyPrefix = "sku-")@DistributedLock(key = "#dto.sku", lockTime = 10L, keyPrefix = "sku-")public R<Boolean> editSupplierInfo(@RequestBody @Validated ProductSkuSupplierInfoDTO dto) {return R.ok(productSkuSupplierMeasureService.editSupplierInfo(dto));}

#dto.sku是 SpEL表达式。Spring中支持的它都支持的。比如调用静态方法，三目表达式。SpEL 可以使用方法中的任何参数。SpEL表达式参考