🎨 redis 分布式锁

src/main/java/utils/redis/RedisCacheUtils.java

@@ -1,13 +1,17 @@
 package utils.redis;
 
+import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.lang3.StringUtils;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.data.redis.core.script.DefaultRedisScript;
 import org.springframework.data.redis.serializer.StringRedisSerializer;
 import org.springframework.stereotype.Component;
 
 import java.math.BigDecimal;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
@@ -15,12 +19,16 @@ import java.util.concurrent.TimeUnit;
  * @author fuhouyin
  * @time 2023/4/11 9:30
  */
+@Slf4j
 @Component
 public class RedisCacheUtils {
 
     @Autowired
     private RedisTemplateProvider redisTemplateProvider;
+    @Autowired
+    private RedisTemplate redisTemplate;
     private final StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
+    public static final String SETNX_SCRIPT = "return redis.call('setnx',KEYS[1], ARGV[1])";
 
     public void setValue(String key, Object value){
         RedisTemplate redisTemplate = getRedisTemplate();
@@ -88,10 +96,50 @@ public class RedisCacheUtils {
         return result;
     }
 
+    /**
+     * 指定缓存失效时间
+     */
+    public void expire(String key, long time) {
+        redisTemplate.expire(key, time, TimeUnit.MILLISECONDS);
+    }
+    /**
+     * 根据key 获取过期时间
+     *
+     * @param key 键 不能为null
+     * @return 时间(毫秒) 返回0代表为永久有效
+     */
+    public long getExpire(String key) {
+        return redisTemplate.getExpire(key, TimeUnit.MILLISECONDS);
+    }
+
     public Boolean lock(String key){
         return getRedisTemplate().opsForValue().setIfAbsent(key, BigDecimal.ZERO.intValue());
     }
 
+    /**
+     * redis实现分布式锁
+     * @param key time是：毫秒毫秒毫秒毫秒毫秒
+     * @return
+     */
+    public boolean lock(String key,Long time) {
+        //自定义脚本
+        DefaultRedisScript<List> script = new DefaultRedisScript<>(SETNX_SCRIPT, List.class);
+        //执行脚本,传入参数,由于value没啥用,这里随便写死的"1"
+        List<Long> rst = (List<Long>) redisTemplate.execute(script, Collections.singletonList(key), "1");
+        //返回1,表示设置成功,拿到锁
+        if(rst.get(0) == 1){
+            log.info(key+"成功拿到锁");
+            //设置过期时间
+            expire(key,time);
+            log.info(key+"已成功设置过期时间:"+time +" 秒");
+            return true;
+        }else{
+            long expire = getExpire(key);
+            log.info(key+"未拿到到锁,还有"+expire+"释放");
+            return false;
+        }
+    }
+
     public Boolean tryLock(String key){
         try {
             for (int i = 0; i < 3; i++) {