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Mybatis的cache

时间:2014-10-07 11:39:33      阅读:376      评论:0      收藏:0      [点我收藏+]

相关类:org.apache.ibatis.executor.CachingExecutor

 

相关代码:

  public <E> List<E> query(MappedStatement ms, Object parameterObject, RowBounds rowBounds, ResultHandler resultHandler) throws SQLException {
    BoundSql boundSql = ms.getBoundSql(parameterObject);
    CacheKey key = createCacheKey(ms, parameterObject, rowBounds, boundSql);
    return query(ms, parameterObject, rowBounds, resultHandler, key, boundSql);
  }

 

 

从CacheKey key = createCacheKey(ms, parameterObject, rowBounds, boundSql);可以看出,当下列四个元素相同时会使用cache:

MappedStatement(一般为xml中定义)、parameterObject(传递给xml的参数)、rowBounds(分页参数)、boundSql(最终sql,由MappedStatement和parameterObject决定)

createCacheKey的代码:

  public CacheKey createCacheKey(MappedStatement ms, Object parameterObject, RowBounds rowBounds, BoundSql boundSql) {
    if (closed) throw new ExecutorException("Executor was closed.");
    CacheKey cacheKey = new CacheKey();
    cacheKey.update(ms.getId());
    cacheKey.update(rowBounds.getOffset());
    cacheKey.update(rowBounds.getLimit());
    cacheKey.update(boundSql.getSql());
    List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
    if (parameterMappings.size() > 0 && parameterObject != null) {
      TypeHandlerRegistry typeHandlerRegistry = ms.getConfiguration().getTypeHandlerRegistry();
      if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {
        cacheKey.update(parameterObject);
      } else {
        MetaObject metaObject = configuration.newMetaObject(parameterObject);
        for (ParameterMapping parameterMapping : parameterMappings) {
          String propertyName = parameterMapping.getProperty();
          if (metaObject.hasGetter(propertyName)) {
            cacheKey.update(metaObject.getValue(propertyName));
          } else if (boundSql.hasAdditionalParameter(propertyName)) {
            cacheKey.update(boundSql.getAdditionalParameter(propertyName));
          }
        }
      }
    }
    return cacheKey;
  }

 

Mybatis的cache

原文:http://www.cnblogs.com/chanedi/p/4009059.html

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