redis分布式锁

1. redis分布式锁

1.1. 实现工具

public class RedisTool {
 
    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
     * @param requestId 请求标识
     * @param expireTime 超期时间
     * @return 是否获取成功
     */
    public static boolean tryGetDistributedLock(Jedis jedis, String lockKey, String requestId, int expireTime) {
 
        String result = jedis.set(lockKey, requestId, SET_IF_NOT_EXIST, SET_WITH_EXPIRE_TIME, expireTime);
 
        if (LOCK_SUCCESS.equals(result)) {
            return true;
        }
        return false;
 
    }


    /**
     * 释放分布式锁
     * @param jedis Redis客户端
     * @param lockKey 锁
     * @param requestId 请求标识
     * @return 是否释放成功
     */
    public static boolean releaseDistributedLock(Jedis jedis, String lockKey, String requestId) {

        String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
        Object result = jedis.eval(script, Collections.singletonList(lockKey), Collections.singletonList(requestId));

        if (RELEASE_SUCCESS.equals(result)) {
            return true;
        }
        return false;

    }
 
}

1.2. redis配置

package com.zhiyis.common.config;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

import java.lang.reflect.Method;


@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport {

    private static Logger logger = LoggerFactory.getLogger(RedisConfig.class);

    @Value("${spring.redis.host}")
    private String redisHost;

    @Value("${spring.redis.port}")
    private int redisPort;

    @Value("${spring.redis.timeout}")
    private int redisTimeout;

    @Value("${spring.redis.password}")
    private String redisAuth;

    @Value("${spring.redis.database}")
    private int redisDb;

    @Value("${spring.redis.pool.max-active}")
    private int maxActive;

    @Value("${spring.redis.pool.max-wait}")
    private int maxWait;

    @Value("${spring.redis.pool.max-idle}")
    private int maxIdle;

    @Value("${spring.redis.pool.min-idle}")
    private int minIdle;

    @Bean
    @Override
    public KeyGenerator keyGenerator() {
        return new KeyGenerator() {
            @Override
            public Object generate(Object target, Method method, Object... params) {
                StringBuilder sb = new StringBuilder();
                sb.append(target.getClass().getName());
                sb.append(method.getName());
                for (Object obj : params) {
                    sb.append(obj.toString());
                }
                return sb.toString();
            }
        };
    }

    @Bean
    public CacheManager redisCacheManager() {
        RedisCacheManager cacheManager = new RedisCacheManager(redisTemplate());
        //默认300秒过期
        cacheManager.setDefaultExpiration(300);
        // 启动时加载远程缓存
        cacheManager.setLoadRemoteCachesOnStartup(true);
        //是否使用前缀生成器
        cacheManager.setUsePrefix(true);
        return cacheManager;
    }



    @Bean
    public RedisConnectionFactory redisConnectionFactory() {
        JedisPoolConfig poolConfig = new JedisPoolConfig();
        poolConfig.setMaxTotal(maxActive);
        poolConfig.setMaxIdle(maxIdle);
        poolConfig.setMaxWaitMillis(maxWait);
        poolConfig.setMinIdle(minIdle);
        poolConfig.setTestOnBorrow(true);
        poolConfig.setTestOnReturn(false);
        poolConfig.setTestWhileIdle(true);
        JedisConnectionFactory jedisConnectionFactory = new JedisConnectionFactory(poolConfig);
        jedisConnectionFactory.setPassword(redisAuth);
        jedisConnectionFactory.setHostName(redisHost);
        jedisConnectionFactory.setDatabase(redisDb);
        jedisConnectionFactory.setPort(redisPort);
        jedisConnectionFactory.setTimeout(redisTimeout);
        return jedisConnectionFactory;
    }

    @Bean
    public RedisTemplate<String, Object> redisTemplate() {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        Jackson2JsonRedisSerializer<Object> serializer = jackson2JsonRedisSerializer();
        redisTemplate.setConnectionFactory(redisConnectionFactory());
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setValueSerializer(serializer);
        redisTemplate.setHashKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashValueSerializer(serializer);
        return redisTemplate;
    }

    @Bean
    public Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer() {
        final Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class);
        final ObjectMapper objectMapper = Jackson2ObjectMapperBuilder
                .json().build();
        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
        return jackson2JsonRedisSerializer;
    }

    @Bean
    public JedisPool redisPoolFactory() throws Exception {
        JedisPoolConfig jedisPoolConfig = new JedisPoolConfig();
        jedisPoolConfig.setMaxIdle(maxIdle);
        jedisPoolConfig.setMaxWaitMillis(maxWait);
        // 连接耗尽时是否阻塞, false报异常,ture阻塞直到超时, 默认true
        jedisPoolConfig.setBlockWhenExhausted(true);
        // 是否启用pool的jmx管理功能, 默认true
        jedisPoolConfig.setJmxEnabled(true);
        JedisPool jedisPool = new JedisPool(jedisPoolConfig, redisHost, redisPort, redisTimeout, redisAuth);
        return jedisPool;
    }
}

上述主要用到 redisPoolFactory方法，用来初始化jedispool，缓存等不需要用到可以删除

1.3. 使用aop用注解的形式来进行分布式锁的包裹

/**
 * redis分布式锁注解
 * @author laoliangliang
 * @date 2019/2/20 10:27
 */
public @interface JedisLock {
}

package com.zhiyis.framework.aop;

import com.zhiyis.common.utils.RedisTool;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;

import java.lang.reflect.Method;
import java.util.UUID;

/**
 * redis分布式锁aop实现
 *
 * @author laoliangliang
 * @date 2019/1/10 17:04
 */
@Slf4j
@Component
@Aspect
public class JedisLockAspect {

    @Pointcut(value = "(execution(* *.*(..)) && @annotation(com.zhiyis.framework.annotation.JedisLock))")
    private void pointcut() {
    }

    @Autowired
    private JedisPool jedisPool;

    @Around("pointcut()")
    public Object lockAroud(ProceedingJoinPoint joinPoint) throws Throwable {

        //获取切入方法的数据
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        //获取切入方法
        Method method = signature.getMethod();
        String lockKey = method.getName();
        String uuid = UUID.randomUUID().toString();
        try (Jedis jedis = jedisPool.getResource()) {
            boolean lock = RedisTool.tryGetDistributedLock(jedis, lockKey, uuid, 60000);
            if (lock) {
                Object proceed = joinPoint.proceed();
                RedisTool.releaseDistributedLock(jedis, lockKey, uuid);
                return proceed;
            }
        } catch (Throwable e) {
            log.error("tradeCode接口错误", e);
            throw e;
        }
        return null;
    }


}

使用

1. 使用就很简单了，在要使用分布式锁的方法上面直接加上 @JedisLock 注解

参考 https://www.cnblogs.com/linjiqin/p/8003838.html