Introducing redis distributed lock

Recommended (free): redis

Redisson

The difference between redisson and self-encapsulation is as follows (scenario):

1. If redisson does not acquire the lock, it will wait until it acquires the lock.
2. If the other two methods do not obtain the lock, they will give up and the business code will not be executed.

<dependency>
    <groupid>org.redisson</groupid>
    <artifactid>redisson-spring-boot-starter</artifactid>
    <version>3.13.6</version></dependency>

@Autowiredprivate Redisson redisson;@GetMapping("/redissonLock")public String redissonLock() {
    log.info("进入了方法");
    RLock lock = redisson.getLock("redissonLock");
    try {
        lock.lock(30, TimeUnit.SECONDS);
        Thread.sleep(10000);
        System.out.println("我是你大哥");
    } catch (InterruptedException e) {
        e.printStackTrace();
    } finally {
    // 如果不释放，不会唤起其他线程，则其他线程会超时过期自动唤醒，不会执行业务代码
        lock.unlock();
    }
    return "运行结束";}

RedisTemplate encapsulates redis lock (1)

<dependency>
   <groupid>org.springframework.boot</groupid>
   <artifactid>spring-boot-starter-data-redis</artifactid></dependency>

package com.util;import org.springframework.dao.DataAccessException;import org.springframework.data.redis.connection.RedisConnection;import org.springframework.data.redis.connection.RedisStringCommands;import org.springframework.data.redis.core.RedisCallback;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.data.redis.core.script.RedisScript;import org.springframework.data.redis.core.types.Expiration;import org.springframework.stereotype.Component;import java.util.Arrays;@Componentpublic class RedisLock {

    private static RedisTemplate redisTemplate;

    private static String script = "if redis.call(\"get\",KEYS[1]) == ARGV[1] then\n" +
            "\treturn redis.call(\"del\",KEYS[1])\n" +
            "else\n" +
            "   \treturn 0\t\n" +
            "end  ";

    public RedisLock(RedisTemplate redisTemplate) {
        RedisLock.redisTemplate = redisTemplate;
    }

    public static Boolean getLock(String key, String value, Long expireTime) {
        RedisStringCommands.SetOption setOption = RedisStringCommands.SetOption.ifAbsent();
        Expiration expiration = Expiration.seconds(expireTime);
        RedisCallback<boolean> booleanRedisCallback = new RedisCallback<boolean>() {
            @Override
            public Boolean doInRedis(RedisConnection connection) throws DataAccessException {
                return connection.set(redisTemplate.getKeySerializer().serialize(key), redisTemplate.getValueSerializer().serialize(value), expiration, setOption);
            }
        };
        return (Boolean) redisTemplate.execute(booleanRedisCallback);
    }

    public static Boolean unLock(String key, String value) {
        RedisScript<boolean> redisScript = RedisScript.of(script, Boolean.class);
        return (Boolean) redisTemplate.execute(redisScript, Arrays.asList(key), value);
    }}</boolean></boolean></boolean>

@GetMapping("/redisLock")public String redisLock() {
    log.info("进入了方法");
    String key = "redisLock";
    String uuid = UUID.randomUUID().toString();
    try {
        if (RedisLock.getLock(key, uuid, 30L)) {
            log.info("进入了锁");
            Thread.sleep(10000);
        }
    } catch (InterruptedException e) {
        e.printStackTrace();
    } finally {
        RedisLock.unLock(key, uuid);
    }
    log.info("方法执行完成");
    return "程序结束";}

RedisTemplate encapsulates redis lock (2)

package com.util;import lombok.extern.slf4j.Slf4j;import org.springframework.dao.DataAccessException;import org.springframework.data.redis.connection.RedisConnection;import org.springframework.data.redis.connection.RedisStringCommands;import org.springframework.data.redis.core.RedisCallback;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.data.redis.core.script.RedisScript;import org.springframework.data.redis.core.types.Expiration;import java.util.Arrays;import java.util.UUID;@Slf4jpublic class HighRedisLock implements AutoCloseable{

    private RedisTemplate redisTemplate;

    private String key;

    private String value;

    private Long expireTime;

    private static String script = "if redis.call(\"get\",KEYS[1]) == ARGV[1] then\n" +
            "\treturn redis.call(\"del\",KEYS[1])\n" +
            "else\n" +
            "   \treturn 0\t\n" +
            "end  ";

    public HighRedisLock(RedisTemplate redisTemplate, String key, Long expireTime) {
        this.redisTemplate = redisTemplate;
        this.key = key;
        this.value = UUID.randomUUID().toString();
        this.expireTime = expireTime;
    }

    public Boolean getLock() {
        RedisStringCommands.SetOption setOption = RedisStringCommands.SetOption.ifAbsent();
        Expiration expiration = Expiration.seconds(expireTime);
        RedisCallback<boolean> booleanRedisCallback = new RedisCallback<boolean>() {
            @Override
            public Boolean doInRedis(RedisConnection connection) throws DataAccessException {
                return connection.set(redisTemplate.getKeySerializer().serialize(key), redisTemplate.getValueSerializer().serialize(value), expiration, setOption);
            }
        };
        return (Boolean) redisTemplate.execute(booleanRedisCallback);
    }

    public Boolean unLock() {
        RedisScript<boolean> redisScript = RedisScript.of(script, Boolean.class);
        return (Boolean) redisTemplate.execute(redisScript, Arrays.asList(key), value);
    }

    @Override
    public void close() throws Exception {
        unLock();
    }}</boolean></boolean></boolean>

@Autowiredprivate RedisTemplate redisTemplate;@GetMapping("/highRedisLock")public String highRedisLock() {
    log.info("进入了方法");
    try (HighRedisLock redisLock = new HighRedisLock(redisTemplate, "highRedisLock", 30L)) {
        if (redisLock.getLock()) {
            log.info("进入了锁");
            Thread.sleep(10000);
        }
    } catch (InterruptedException e) {
        e.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    }
    log.info("方法执行完成");
    return "程序结束";}

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