SpringBank 开发日志 Mybatis 使用redis 作为二级缓存时，无法通过cacheEnabled=false 将其关闭

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>

    <settings>

        <!-- 是否开启二级缓存 默认为true -->

        <setting name="cacheEnabled" value="false"/>

        <!-- 是否懒加载 -->

        <setting name="lazyLoadingEnabled" value="false" />

    </settings>

</configuration>

即使如此，当我的mappler里面有<cache type="com.springbank.dao.support.cache.redis.RedisCache" />，查询这张表时，我发现mybatis仍然去查询redis

### Error querying database.  Cause: org.springframework.data.redis.RedisConnectionFailureException: Cannot get Jedis connection; nested exception is java.lang.NullPointerException

### Cause: org.springframework.data.redis.RedisConnectionFailureException: Cannot get Jedis connection; nested exception is java.lang.NullPointerException

	at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)

	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)

	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)

	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:77)

	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

	at java.lang.reflect.Method.invoke(Method.java:498)

	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:434)

	... 18 more

Caused by: org.springframework.data.redis.RedisConnectionFailureException: Cannot get Jedis connection; nested exception is java.lang.NullPointerException

	at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.fetchJedisConnector(JedisConnectionFactory.java:198)

	at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.getConnection(JedisConnectionFactory.java:345)

	at com.springbank.dao.support.cache.redis.RedisCache.getObject(RedisCache.java:62)

	at org.apache.ibatis.cache.decorators.LoggingCache.getObject(LoggingCache.java:57)

	at org.apache.ibatis.cache.decorators.TransactionalCache.getObject(TransactionalCache.java:68)

	at org.apache.ibatis.cache.TransactionalCacheManager.getObject(TransactionalCacheManager.java:35)

	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:101)

	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83)

	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)

	... 25 more

Caused by: java.lang.NullPointerException

	at redis.clients.jedis.BinaryJedis.<init>(BinaryJedis.java:101)

	at redis.clients.jedis.Jedis.<init>(Jedis.java:78)

	at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.fetchJedisConnector(JedisConnectionFactory.java:193)

根据异常栈，在CachingExecutor.java:101 看到如下代码

@Override

  public <E> List<E> query(MappedStatement ms, Object parameterObject, RowBounds rowBounds, ResultHandler resultHandler, CacheKey key, BoundSql boundSql)

      throws SQLException {

    Cache cache = ms.getCache();

    if (cache != null) {

      flushCacheIfRequired(ms);

      if (ms.isUseCache() && resultHandler == null) {

        ensureNoOutParams(ms, parameterObject, boundSql);

        @SuppressWarnings("unchecked")

        List<E> list = (List<E>) tcm.getObject(cache, key);

        if (list == null) {

          list = delegate.<E> query(ms, parameterObject, rowBounds, resultHandler, key, boundSql);

          tcm.putObject(cache, key, list); // issue #578 and #116

        }

        return list;

      }

    }

    return delegate.<E> query(ms, parameterObject, rowBounds, resultHandler, key, boundSql);

  }

于是我想，这里cache变量要是null就好了

======================================以上都是无用功======================================

好吧，我发现我错怪mybatis了，最后我发现我的mybatis-config.xml文件根本没有生效

<!-- spring和MyBatis完美整合，不需要mybatis的配置映射文件 -->

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">

        <property name="dataSource" ref="dataSource" />

        <property name="configLocation" value="classpath:mybatis-config.xml" />

        <property name="mapperLocations">

            <list>

                <value>classpath*:com/springbank/dao/generate/mapper/*.xml</value>

                <value>classpath*:com/springbank/dao/extend/mapper/*.xml</value>

            </list>

        </property>

    </bean>

而没有生效的原因就是我忘记了配上面红色部分