分布式锁Lock4J 使用总结

小鱼儿 2024-04-23 21:25 33阅读 0赞

## Lok4j 简介 ##

lock4j是一个分布式锁组件，其提供了多种不同的支持以满足不同性能和环境的需求。

立志打造一个简单但富有内涵的分布式锁组件。

### 特点 ###

*  简单易用，功能强大，扩展性强。
 *  支持redission,redisTemplate,zookeeper。可混用，支持扩展

## Docker 安装Redis ##

请参考文章：[Docker 安装Redis][Docker _Redis]

## Docker 安装ZooKeeper ##

请参考文章:[Docker 安装Zookeeper][Docker _Zookeeper]

## SpringBoot 集成Lock4j ##

### Lock4j 之Reids 版本 ###

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <parent>
            <artifactId>SpringBootCase</artifactId>
            <groupId>org.example</groupId>
            <version>1.0-SNAPSHOT</version>
        </parent>
        <modelVersion>4.0.0</modelVersion>
    
        <artifactId>SpringBoot-Lock4J</artifactId>
    
        <properties>
            <maven.compiler.source>8</maven.compiler.source>
            <maven.compiler.target>8</maven.compiler.target>
            <mybatisplus-spring-boot-starter.version>3.4.3</mybatisplus-spring-boot-starter.version>
            <mysql-spring-boot-starter.version>8.0.19</mysql-spring-boot-starter.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-boot-starter</artifactId>
                <version>${mybatisplus-spring-boot-starter.version}</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql-spring-boot-starter.version}</version>
            </dependency>
            
            
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>lock4j-redis-template-spring-boot-starter</artifactId>
                <version>2.2.4</version>
            </dependency>
        </dependencies>
    
    </project>

application.yml 之Redis 配置

server:
      port: 8086
    spring:
      datasource:
        driver-class-name: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://192.168.43.10:3306/bill?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC&autoReconnect=true
        username: root
        password: 123456
        hikari:
          minimum-idle: 10
          maximum-pool-size: 20
          idle-timeout: 500000
          max-lifetime: 540000
          connection-timeout: 60000
          connection-test-query: select 1
      redis:
        database: 0
        host: 192.168.43.10
        port: 6379
        jedis:
          pool:
            max-active: 200
            max-wait: -1
            max-idle: 10
            min-idle: 0
        timeout: 6000
    
    mybatis-plus:
      mapper-locations: classpath:mapper/*.xml
      type-aliases-package: cn.zzg.mybatisplus.entity

controller 使用Lock4j 注解，实现分布式锁功能

package cn.zzg.lock.controller;
    
    import com.baomidou.lock.annotation.Lock4j;
    import org.springframework.web.bind.annotation.*;
    
    @RestController
    @RequestMapping("/lock4j")
    public class Lock4JController {
    
        @GetMapping("/lockMethod")
        @Lock4j(keys = {"#key"}, acquireTimeout = 1000, expire = 10000)
        public String lockMethod(@RequestParam String key){
            try {
                Thread.sleep(5000);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
            return new String(key);
        }
    
    }

### Lock4j 之Redission版本 ###

pom.xml

application.yml 配置文件

server:
      port: 8089
    spring:
      redis:
        database: 0
        host: 192.168.43.10
        port: 6379
        jedis:
          pool:
            max-active: 200
            max-wait: -1
            max-idle: 10
            min-idle: 0
        timeout: 6000

controller 使用Lock4j 注解，实现分布式锁功能

package cn.zzg.lock4j.controller;
    
    import com.baomidou.lock.annotation.Lock4j;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    @RequestMapping("/lock4j")
    public class Lock4JController {
    
        @GetMapping("/lockMethod")
        @Lock4j(keys = {"#key"}, acquireTimeout = 1000, expire = 10000)
        public String lockMethod(@RequestParam String key){
            try {
                Thread.sleep(5000);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
            return new String(key);
        }
    
    }

### Lock4j 之ZooKeeper 版本 ###

pom.xml

application.yml 之zookeeper配置

server:
      port: 8087
    spring:
      coordinate:
        zookeeper:
          zkServers: 192.168.43.10:2181

controller 使用Lock4j 注解，实现分布式锁功能

package cn.zzg.lock.controller;
    
    import com.baomidou.lock.annotation.Lock4j;
    import com.baomidou.lock.executor.ZookeeperLockExecutor;
    import org.springframework.web.bind.annotation.*;
    
    @RestController
    @RequestMapping("/lock4j")
    public class Lock4JController {
    
        @GetMapping("/lockMethod")
        @Lock4j(keys = {"#key"}, acquireTimeout = 1000, expire = 10000, executor = ZookeeperLockExecutor.class)
        public String lockMethod(@RequestParam String key){
            try {
                Thread.sleep(5000);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
            return new String(key);
        }
    
    }

## Lock4J 注解详解 ##

![cc3354f600c44298985689be31aa6930.png][]

## Lock4J 高级使用 ##

### 1、配置获取锁超时时间和锁过期时间。 ###

lock4j:
      acquire-timeout: 3000 #默认值3s，可不设置
      expire: 30000 #默认值30s，可不设置
      primary-executor: com.baomidou.lock.executor.RedisTemplateLockExecutor #默认redisson>redisTemplate>zookeeper，可不设置
      lock-key-prefix: lock4j #锁key前缀, 默认值lock4j，可不设置

acquire-timeout /排队时长，超出这个时间退出队列，并抛出超时异常。  
expire 锁过期时间 。 主要是防止死锁。默认30秒是为了兼容绝大部分场景。

### 2、自定义执行器。 ###

前提条件必须继承抽象类：com.baomidou.lock.executor.AbstractLockExecutor<T>

ZooKeeper 版本执行器之ZookeeperLockExecutor

//
    // Source code recreated from a .class file by IntelliJ IDEA
    // (powered by FernFlower decompiler)
    //
    
    package com.baomidou.lock.executor;
    
    import java.util.concurrent.TimeUnit;
    import org.apache.curator.framework.CuratorFramework;
    import org.apache.curator.framework.imps.CuratorFrameworkState;
    import org.apache.curator.framework.recipes.locks.InterProcessMutex;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    public class ZookeeperLockExecutor extends AbstractLockExecutor<InterProcessMutex> {
        private static final Logger log = LoggerFactory.getLogger(ZookeeperLockExecutor.class);
        private final CuratorFramework curatorFramework;
    
        public InterProcessMutex acquire(String lockKey, String lockValue, long expire, long acquireTimeout) {
            if (!CuratorFrameworkState.STARTED.equals(this.curatorFramework.getState())) {
                log.warn("instance must be started before calling this method");
                return null;
            } else {
                String nodePath = "/curator/lock4j/%s";
    
                try {
                    InterProcessMutex mutex = new InterProcessMutex(this.curatorFramework, String.format(nodePath, lockKey));
                    boolean locked = mutex.acquire(acquireTimeout, TimeUnit.MILLISECONDS);
                    return (InterProcessMutex)this.obtainLockInstance(locked, mutex);
                } catch (Exception var10) {
                    return null;
                }
            }
        }
    
        public boolean releaseLock(String key, String value, InterProcessMutex lockInstance) {
            try {
                lockInstance.release();
                return true;
            } catch (Exception var5) {
                log.warn("zookeeper lock release error", var5);
                return false;
            }
        }
    
        public ZookeeperLockExecutor(final CuratorFramework curatorFramework) {
            this.curatorFramework = curatorFramework;
        }
    }

Redis 版本执行器之RedisTemplateLockExecutor

//
    // Source code recreated from a .class file by IntelliJ IDEA
    // (powered by FernFlower decompiler)
    //
    
    package com.baomidou.lock.executor;
    
    import java.util.Collections;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.data.redis.core.StringRedisTemplate;
    import org.springframework.data.redis.core.script.DefaultRedisScript;
    import org.springframework.data.redis.core.script.RedisScript;
    
    public class RedisTemplateLockExecutor extends AbstractLockExecutor<String> {
        private static final Logger log = LoggerFactory.getLogger(RedisTemplateLockExecutor.class);
        private static final RedisScript<String> SCRIPT_LOCK = new DefaultRedisScript("return redis.call('set',KEYS[1],ARGV[1],'NX','PX',ARGV[2])", String.class);
        private static final RedisScript<String> SCRIPT_UNLOCK = new DefaultRedisScript("if redis.call('get',KEYS[1]) == ARGV[1] then return tostring(redis.call('del', KEYS[1])==1) else return 'false' end", String.class);
        private static final String LOCK_SUCCESS = "OK";
        private final StringRedisTemplate redisTemplate;
    
        public String acquire(String lockKey, String lockValue, long expire, long acquireTimeout) {
            String lock = (String)this.redisTemplate.execute(SCRIPT_LOCK, this.redisTemplate.getStringSerializer(), this.redisTemplate.getStringSerializer(), Collections.singletonList(lockKey), new Object[]{lockValue, String.valueOf(expire)});
            boolean locked = "OK".equals(lock);
            return (String)this.obtainLockInstance(locked, lock);
        }
    
        public boolean releaseLock(String key, String value, String lockInstance) {
            String releaseResult = (String)this.redisTemplate.execute(SCRIPT_UNLOCK, this.redisTemplate.getStringSerializer(), this.redisTemplate.getStringSerializer(), Collections.singletonList(key), new Object[]{value});
            return Boolean.parseBoolean(releaseResult);
        }
    
        public RedisTemplateLockExecutor(final StringRedisTemplate redisTemplate) {
            this.redisTemplate = redisTemplate;
        }
    }

### 3、自定义Key生成器 ###

前提条件必须实现：com.baomidou.lock.LockKeyBuilder 接口

默认Key生成器：DefaultLockKeyBuilder

//
    // Source code recreated from a .class file by IntelliJ IDEA
    // (powered by FernFlower decompiler)
    //
    
    package com.baomidou.lock;
    
    import java.lang.reflect.Method;
    import java.util.ArrayList;
    import java.util.List;
    import org.aopalliance.intercept.MethodInvocation;
    import org.springframework.beans.factory.BeanFactory;
    import org.springframework.context.expression.BeanFactoryResolver;
    import org.springframework.context.expression.MethodBasedEvaluationContext;
    import org.springframework.core.DefaultParameterNameDiscoverer;
    import org.springframework.core.ParameterNameDiscoverer;
    import org.springframework.expression.BeanResolver;
    import org.springframework.expression.ExpressionParser;
    import org.springframework.expression.spel.standard.SpelExpressionParser;
    import org.springframework.expression.spel.support.StandardEvaluationContext;
    import org.springframework.util.StringUtils;
    
    public class DefaultLockKeyBuilder implements LockKeyBuilder {
        private static final ParameterNameDiscoverer NAME_DISCOVERER = new DefaultParameterNameDiscoverer();
        private static final ExpressionParser PARSER = new SpelExpressionParser();
        private BeanResolver beanResolver;
    
        public DefaultLockKeyBuilder(BeanFactory beanFactory) {
            this.beanResolver = new BeanFactoryResolver(beanFactory);
        }
    
        public String buildKey(MethodInvocation invocation, String[] definitionKeys) {
            Method method = invocation.getMethod();
            return definitionKeys.length <= 1 && "".equals(definitionKeys[0]) ? "" : this.getSpelDefinitionKey(definitionKeys, method, invocation.getArguments());
        }
    
        protected String getSpelDefinitionKey(String[] definitionKeys, Method method, Object[] parameterValues) {
            StandardEvaluationContext context = new MethodBasedEvaluationContext((Object)null, method, parameterValues, NAME_DISCOVERER);
            context.setBeanResolver(this.beanResolver);
            List<String> definitionKeyList = new ArrayList(definitionKeys.length);
            String[] var6 = definitionKeys;
            int var7 = definitionKeys.length;
    
            for(int var8 = 0; var8 < var7; ++var8) {
                String definitionKey = var6[var8];
                if (definitionKey != null && !definitionKey.isEmpty()) {
                    String key = (String)PARSER.parseExpression(definitionKey).getValue(context, String.class);
                    definitionKeyList.add(key);
                }
            }
    
            return StringUtils.collectionToDelimitedString(definitionKeyList, ".", "", "");
        }
    }

### 4、自定义锁获取失败策略 ###

前提条件必须实现：com.baomidou.lock.LockFailureStrategy 接口

默认失败策略:DefaultLockFailureStrategy

//
    // Source code recreated from a .class file by IntelliJ IDEA
    // (powered by FernFlower decompiler)
    //
    
    package com.baomidou.lock;
    
    import com.baomidou.lock.exception.LockFailureException;
    import java.lang.reflect.Method;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    public class DefaultLockFailureStrategy implements LockFailureStrategy {
        private static final Logger log = LoggerFactory.getLogger(DefaultLockFailureStrategy.class);
        protected static String DEFAULT_MESSAGE = "request failed,please retry it.";
    
        public DefaultLockFailureStrategy() {
        }
    
        public void onLockFailure(String key, Method method, Object[] arguments) {
            throw new LockFailureException(DEFAULT_MESSAGE);
        }
    }

### 5、手动获取/释放锁 ###

通用方法：

@Service
    public class CommonService {
        @Autowired
        private LockTemplate lockTemplate;
    
        public void commonLock(String bizId) {
            // 各种查询操作 不上锁
            // ...
            // 获取锁
            final LockInfo lockInfo = lockTemplate.lock(bizId, 30000L, 5000L, RedissonLockExecutor.class);
            if (null == lockInfo) {
                throw new RuntimeException("业务处理中,请稍后再试");
            }
            // 获取锁成功，处理业务
            try {
                System.out.println("执行普通方法 , 当前线程:" + Thread.currentThread().getName());
            } finally {
                //释放锁
                lockTemplate.releaseLock(lockInfo);
            }
            //结束
        }
    }

**参考资料**

官网地址：[Lock4J][]

[Docker _Redis]: https://blog.csdn.net/zhouzhiwengang/article/details/135356134?spm=1001.2014.3001.5501
[Docker _Zookeeper]: https://blog.csdn.net/zhouzhiwengang/article/details/126168972
[cc3354f600c44298985689be31aa6930.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/23/bc056fef98f5425c88104b8a0000c82d.png
[Lock4J]: https://gitee.com/baomidou/lock4j