RunJettyRun 插件使用(spring-data-redis/jedis-2.7.2不兼容)

最新推荐文章于 2023-05-03 14:01:13 发布

原创最新推荐文章于 2023-05-03 14:01:13 发布 · 471 阅读

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#jedis-2.7.2.jar #jedis-2.7.3.jar #spring-data-redis-1.5.0.RELEASE.jar

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当使用Spring Data Redis 1.5.0.RELEASE与Jedis 2.7.2及2.7.3时，由于版本不兼容导致NullPointerException。文章分析了错误原因并提出了解决方案。

在Eclipse的RunJettyRun(jetty 7.6.8.v20121106)使用jetty时，在项目中使用到了spring-data-redis-1.5.0.RELEASE.jar、jedis-2.7.2.jar、jedis-2.7.3.jar，于是如以下代码方式访问Redis时：

private static RedisTemplate<String, Object> redisTemplate = ...;
redisTemplate.opsForHash().put(CACHE_NAME + key, hashKey, value);

就会出现如下错误:

java.lang.ExceptionInInitializerError
	at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.getConnection(JedisConnectionFactory.java:252)
	at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.getConnection(JedisConnectionFactory.java:58)
	at org.springframework.data.redis.core.RedisConnectionUtils.doGetConnection(RedisConnectionUtils.java:128)
	at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:91)
	at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:78)
	at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:178)
	at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:153)
	at org.springframework.data.redis.core.AbstractOperations.execute(AbstractOperations.java:86)
	at org.springframework.data.redis.core.DefaultHashOperations.put(DefaultHashOperations.java:169)

.........

java.lang.NullPointerException
	at org.springframework.util.ReflectionUtils.makeAccessible(ReflectionUtils.java:455)
	at org.springframework.data.redis.connection.jedis.JedisConnection.<clinit>(JedisConnection.java:108)
	at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.getConnection(JedisConnectionFactory.java:252)
	at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.getConnection(JedisConnectionFactory.java:58)
	at org.springframework.data.redis.core.RedisConnectionUtils.doGetConnection(RedisConnectionUtils.java:128)
	at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:91)
	at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:78)
	at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:178)
	at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:153)
	at org.springframework.data.redis.core.AbstractOperations.execute(AbstractOperations.java:86)
	at org.springframework.data.redis.core.DefaultHashOperations.put(DefaultHashOperations.java:169)

查源码时发现在进行spring-data-redis-1.5.0.RELEASE.jar包下的JedisConnection类中静态块执行的时候失败报出NullPointerException，源码如下所示：

static {
		CLIENT_FIELD = ReflectionUtils.findField(BinaryJedis.class, "client", Client.class);
		ReflectionUtils.makeAccessible(CLIENT_FIELD);
		SEND_COMMAND = ReflectionUtils.findMethod(Connection.class, "sendCommand", new Class[] { Command.class,
				byte[][].class });
		ReflectionUtils.makeAccessible(SEND_COMMAND);
		GET_RESPONSE = ReflectionUtils.findMethod(Queable.class, "getResponse", Builder.class);
		ReflectionUtils.makeAccessible(GET_RESPONSE);
	}

发现在反射获取Connection的sendCommand方法授权时，出现错误，通过查源码发现问题出现在了jedis-2.7.3.jar、jedis-2.7.2.jar 中的Connection的sendCommand的方法，2.7.2对该方法的Command参数进行了升级，与jedis-2.7.3又将2.7.2的改进还原了，从而不兼容导致初始化错误的出现。

其中jedis-2.7.3.jar的 Connection源码如下所示：

protected Connection sendCommand(final Command cmd, final String... args) {
		final byte[][] bargs = new byte[args.length][];
		for (int i = 0; i < args.length; i++) {
			bargs[i] = SafeEncoder.encode(args[i]);
		}
		return sendCommand(cmd, bargs);
    }
	public static enum Command {
		PING,.....;

		public final byte[] raw;

		Command() {
			raw = SafeEncoder.encode(this.name());
		}
    }

其中jedis-2.7.2.jar的 Connection源码如下所示：

 protected Connection sendCommand(final ProtocolCommand cmd, final String... args) {
		final byte[][] bargs = new byte[args.length][];
		for (int i = 0; i < args.length; i++) {
		  bargs[i] = SafeEncoder.encode(args[i]);
		}
		return sendCommand(cmd, bargs);
	}
	public static enum Command implements ProtocolCommand {
		PING,..... ERGE;

		private final byte[] raw;

		Command() {
		  raw = SafeEncoder.encode(this.name());
		}

		@Override
		public byte[] getRaw() {
		  return raw;
		}
  }

先说解决办法将spring-data-redis升级到spring-data-redis-1.6.0.RELEASE.jar，其中JedisConnection的静态块如下所示：

static {

		CLIENT_FIELD = ReflectionUtils.findField(BinaryJedis.class, "client", Client.class);
		ReflectionUtils.makeAccessible(CLIENT_FIELD);

		try {
			Class<?> commandType = ClassUtils.isPresent("redis.clients.jedis.ProtocolCommand", null) ? ClassUtils.forName(
					"redis.clients.jedis.ProtocolCommand", null) : ClassUtils.forName("redis.clients.jedis.Protocol$Command",
					null);

			SEND_COMMAND = ReflectionUtils.findMethod(Connection.class, "sendCommand", new Class[] { commandType,
					byte[][].class });
		} catch (Exception e) {
			throw new NoClassDefFoundError(
					"Could not find required flavor of command required by 'redis.clients.jedis.Connection#sendCommand'.");
		}

		ReflectionUtils.makeAccessible(SEND_COMMAND);

		GET_RESPONSE = ReflectionUtils.findMethod(Queable.class, "getResponse", Builder.class);
		ReflectionUtils.makeAccessible(GET_RESPONSE);
	}

关键一点在于反射调用sendCommand方法时对方法的参数进行了类型判断从而防止了错误的产生。

注：经猜测最终原因可能是jetty在进行类实例化时使用的jedis-2.7.2.jar但是在真正调用时却使用的jedis-2.7.3.jar从而导致错误的产生！