如何從Spring RedisTemplate中獲得Jedis實例

項目組同事提出一個問題，使用Spring RestTemplate不能在“不存在時設值”的同時，設置超時時間。我通過閱讀源代碼，發現Jedis是支持這一指令的，以下代碼來自於 redis.clients.jedis.Jedis

  /**
   * Set the string value as value of the key. The string can't be longer than 1073741824 bytes (1 GB).
   * @param key
   * @param value
   * @param nxxx NX|XX, NX -- Only set the key if it does not already exist. XX -- Only set the key if it already exist.
   * @param expx EX|PX, expire time units: EX = seconds; PX = milliseconds
   * @param time expire time in the units of <code>expx</code>
   * @return Status code reply
   */
  public String set(final String key, final String value, final String nxxx, final String expx, final long time) {

而RestTemplate在封裝時，忽略了返回值。這個返回值表示了設值是否成功，在分佈式鎖等應用場景中是非常重要的。以下代碼來自於org.springframework.data.redis.connection.RedisStringCommands

/**
     * Set {@code value} for {@code key} applying timeouts from {@code expiration} if set and inserting/updating values
     * depending on {@code option}.
     *
     * @param key must not be {@literal null}.
     * @param value must not be {@literal null}.
     * @param expiration can be {@literal null}. Defaulted to {@link Expiration#persistent()}.
     * @param option can be {@literal null}. Defaulted to {@link SetOption#UPSERT}.
     * @since 1.7
     * @see <a href="http://redis.io/commands/set">Redis Documentation: SET</a>
     */
    void set(byte[] key, byte[] value, Expiration expiration, SetOption option);

如何在使用RedisTemplate的同時，獲取Jedis實例，執行相關的方法？以下的方案是從RedisConnectionFactory中獲取Redis連接（JedisConnection實現類），然後使用反射的方法從中取得了Jedis實例，即可直接執行其中的方法，供大家參考

    @Autowired
    private RedisConnectionFactory connectionFactory;

    @RequestMapping("/greeting")
    public String greeting() {
        Field jedisField = ReflectionUtils.findField(JedisConnection.class, "jedis");
        ReflectionUtils.makeAccessible(jedisField);
        System.out.println(connectionFactory.getConnection());
        Jedis jedis = (Jedis) ReflectionUtils.getField(jedisField, connectionFactory.getConnection());
        String result = jedis.set("test-key", "Hello world-", "NX", "EX", 1);

代碼執行後，返回字符串”OK”或者”null”，表示是否設值成功。