由于之前的老的项目一直在使用 Jedis 作为Redis的Java客户端操作数据，Jedis 与JedisPool 作为官方推荐的API，其操作与redis-cli 客户端操作如出一辙，在Spring 大行其道的时代，当然也需要好好了解下RedisTemplate 的操作以及源码。

RedisTemplate的类图如下：

Redis的类图.jpg

通过源码分析：
RedisOperations --定义了Redis的基本操作，提供可扩展性，由 RedisTemplate 实现。
RedisAccessor --定义了RedisTemplate 的一些公有属性
InitializingBean --Spring Bean 对象的初始化，其内部仅仅有一个方法：afterPropertiesSet ，只要是实现该接口，均会在Bean对象初始化时调用该方法

RedisAccessor 源码

public class RedisAccessor implements InitializingBean {

    protected final Log logger = LogFactory.getLog(getClass());

    private RedisConnectionFactory connectionFactory;

    public void afterPropertiesSet() {
        Assert.notNull(getConnectionFactory(), "RedisConnectionFactory is required");
    }

    /**
     * Returns the connectionFactory.
     */
    public RedisConnectionFactory getConnectionFactory() {
        return connectionFactory;
    }

    /**
     * Sets the connection factory.
     */
    public void setConnectionFactory(RedisConnectionFactory connectionFactory) {
        this.connectionFactory = connectionFactory;
    }

InitializingBean 源码

public interface InitializingBean {

    void afterPropertiesSet() throws Exception;

}

RedisTemplate 源码分析

Helper class that simplifies Redis data access code.
简化Redis数据访问代码的Helper类

RedisTemplate的核心方法execute

public <T> T execute(RedisCallback<T> action, boolean exposeConnection, boolean pipeline) {
        Assert.isTrue(initialized, "template not initialized; call afterPropertiesSet() before using it");
        Assert.notNull(action, "Callback object must not be null");

        RedisConnectionFactory factory = getConnectionFactory();
        RedisConnection conn = null;
        try {

            if (enableTransactionSupport) {
                // only bind resources in case of potential transaction synchronization
                conn = RedisConnectionUtils.bindConnection(factory, enableTransactionSupport);
            } else {
                conn = RedisConnectionUtils.getConnection(factory);
            }

            boolean existingConnection = TransactionSynchronizationManager.hasResource(factory);

            RedisConnection connToUse = preProcessConnection(conn, existingConnection);

            boolean pipelineStatus = connToUse.isPipelined();
            if (pipeline && !pipelineStatus) {
                connToUse.openPipeline();
            }

            RedisConnection connToExpose = (exposeConnection ? connToUse : createRedisConnectionProxy(connToUse));
            T result = action.doInRedis(connToExpose);

            // close pipeline
            if (pipeline && !pipelineStatus) {
                connToUse.closePipeline();
            }

            // TODO: any other connection processing?
            return postProcessResult(result, connToUse, existingConnection);
        } finally {

            if (enableTransactionSupport) {
                RedisConnectionUtils.unbindConnection(factory);
            } else {
                RedisConnectionUtils.releaseConnection(conn, factory);
            }
        }
    }

1. 根据RedisConnectionFactory 获取 RedisConnection
2. 执行RedisCallback. doInRedis
3. 返回结果

RedisTemplate String 字符串操作

  public class StringRedisTemplate extends RedisTemplate<String, String> {
    public StringRedisTemplate() {
        RedisSerializer<String> stringSerializer = new StringRedisSerializer();
        setKeySerializer(stringSerializer);
        setValueSerializer(stringSerializer);
        setHashKeySerializer(stringSerializer);
        setHashValueSerializer(stringSerializer);
    }

    public StringRedisTemplate(RedisConnectionFactory connectionFactory) {
        this();
        setConnectionFactory(connectionFactory);
        afterPropertiesSet();
    }

    protected RedisConnection preProcessConnection(RedisConnection connection, boolean existingConnection) {
        return new DefaultStringRedisConnection(connection);
    }
}

未完，待续