mybatis缓存bug

线上定时任务，在执行时，计算出合同金额不对；

查看日志

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2.13 cron

2020-02-13 01:10:00.004 [org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-6] [com.tangdi.jump.bp.service.sqlmap.support.SqlSessionUtils] DEBUG Fetched SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@12af9e28] from current transaction

2020-02-13 01:10:00.004 [org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-6] [com.tangdi.jump.bp.service.sqlmap.impl.SqlMapImpl] DEBUG Opened SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@12af9e28] for iBATIS operation

2020-02-13 01:10:00.004 [org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-6] [com.tangdi.jump.bp.service.sqlmap.support.SqlSessionUtils] DEBUG Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@12af9e28]

2020-02-13 01:10:00.004 [org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-6] [net.tangdi.gxseas.service.AutoRecon] INFO === 日切日期： 2020-02-07

2020-02-13 01:10:00.004 [org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-6] [net.tangdi.gxseas.service.AutoRecon] INFO 任务号:A,任务执行步骤:A01,日切日期:20200207

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定时任务是执行了，切定时记录时间正确是4月13日，但是应该执行4.12日的,为什么执行了4.07日的

一筹莫展后翻看了mybatis的源码，找到BaseExecutor，代码如下

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// Flush the internal cache is force is trueif(ms.isFlushCacheRequired()) {clearLocalCache();  } 

 List list;

try{ queryStack++;

 CacheKey key = createCacheKey(ms,parameter,rowBounds);

list= resultHandler == null ? (List) localCache.getObject(key): null;

if(list!= null) { handleLocallyCachedOutputParameters(ms,key,parameter); }

else{list= queryFromDatabase(ms,parameter,rowBounds,resultHandler,key); } } 

finally { queryStack--; }

if(queryStack == 0) {for(DeferredLoad deferredLoad : deferredLoads) { deferredLoad.load(); } }

 returnlist;}

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resultHandler传入的默认全是null,说明它会缓存拿.最后在日志找到几天的sqlSession都是一样的，证实了缓存猜测；localCache是SqlSession的成员变量.那么就可以断定如果相同的sql在同一个SqlSession执行,就会命中缓存。

解决办法：sql单个查询取消默认缓存

   

mybatis->configuration.xml->setting标签添加：

或者

用插件，添加全局拦截

import org.apache.ibatis.executor.Executor;

import org.apache.ibatis.mapping.MappedStatement;

import org.apache.ibatis.plugin.Interceptor;

import org.apache.ibatis.plugin.Intercepts;

import org.apache.ibatis.plugin.Invocation;

import org.apache.ibatis.plugin.Plugin;

import org.apache.ibatis.plugin.Signature;

import org.apache.ibatis.session.ResultHandler;

import org.apache.ibatis.session.RowBounds;

import java.util.Properties;

/**

* 关掉Mybatis所有查询的一级缓存

* Created by mumubin 2017/4/13.

*/

@Intercepts(@Signature(method = "query", type = Executor.class, args = {MappedStatement.class, Object.class,

        RowBounds.class, ResultHandler.class}))

public class FlushCacheInterceptor implements Interceptor {

    @Override

    public Object intercept(Invocation invocation) throws Throwable {

        MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];

        MappedStatement copy = copyMappedStatementFlushCache(mappedStatement);

        invocation.getArgs()[0] = copy;

        return invocation.proceed();

    }

    /**

    * 复制MappedStatement 并设置FlushCache=true

    * @param mappedStatement

    * @return

    */

    private MappedStatement copyMappedStatementFlushCache(MappedStatement mappedStatement) {

        MappedStatement.Builder builder = new MappedStatement.Builder(mappedStatement.getConfiguration(),

                mappedStatement.getId(), mappedStatement.getSqlSource(), mappedStatement.getSqlCommandType());

        builder.resource(mappedStatement.getResource());

        builder.fetchSize(mappedStatement.getFetchSize());

        builder.statementType(mappedStatement.getStatementType());

        builder.keyGenerator(mappedStatement.getKeyGenerator());

        builder.keyProperty(mappedStatement.getKeyProperty());

        builder.timeout(mappedStatement.getTimeout());

        builder.resultMaps(mappedStatement.getResultMaps());

        builder.resultSetType(mappedStatement.getResultSetType());

        builder.cache(mappedStatement.getCache());

        builder.useCache(mappedStatement.isUseCache());

        builder.parameterMap(mappedStatement.getParameterMap());

        builder.flushCacheRequired(true);

        return builder.build();

    }

    @Override

    public Object plugin(Object o) {

        return Plugin.wrap(o, this);

    }

    @Override

    public void setProperties(Properties properties) {

    }

}