有什么做兼职的好的网站吗,微信小程序平台入口,建网站大公司,如何设置网站域名添加配置mybatis-plus.configuration.cache-enabledtrue在mapper.xml文件中添加cache标签cache size10240 evictionLRU/同一个事务中二级缓存不生效#xff0c;会使用一级缓存#xff0c;因为事务未提交。
执行流程部分
Configuration创建…添加配置mybatis-plus.configuration.cache-enabledtrue在mapper.xml文件中添加cache标签cache size10240 evictionLRU/同一个事务中二级缓存不生效会使用一级缓存因为事务未提交。
执行流程部分
Configuration创建Executor对象public class Configuration{public Executor newExecutor(Transaction transaction, ExecutorType executorType) {executorType executorType null ? defaultExecutorType : executorType;Executor executor new SimpleExecutor(this, transaction);// 根据settings中配置的启用cache创建CachingExecutor包装类if (cacheEnabled) {executor new CachingExecutor(executor);}return (Executor) interceptorChain.pluginAll(executor);}
}CachingExecutor#query查询逻辑public class CachingExecutor implements Executor {public E ListE query(MappedStatement ms, Object parameterObject, RowBounds rowBounds, ResultHandler resultHandler,CacheKey key, BoundSql boundSql) throws SQLException {//1. 从 MappedStatement中获取二级缓存对象如果存在则进入缓存查询逻辑Cache cache ms.getCache();if (cache ! null) {flushCacheIfRequired(ms);if (ms.isUseCache() resultHandler null) {ensureNoOutParams(ms, boundSql);ListE list (ListE) tcm.getObject(cache, key);if (list null) {list delegate.query(ms, parameterObject, rowBounds, resultHandler, key, boundSql);//2. 将数据保存到缓存中注意这里先放入TransactionalCache对象中等待事务提交时回调CachingExecutor#commit时// 调用TransactionalCache#commit - 调用flushPendingEntries将缓存数据写入到cache中,// 所以同一个事务中多次查询无法使用二级缓存中的数据tcm.putObject(cache, key, list); // issue #578 and #116}return list;}}// 3. 非二级缓存逻辑return delegate.query(ms, parameterObject, rowBounds, resultHandler, key, boundSql);}
}TransactionalCache#commit事务提交时回调逻辑public class TransactionalCache{// 事务体骄傲时回调函数 public void commit() {if (clearOnCommit) {delegate.clear();}flushPendingEntries();reset();}private void flushPendingEntries() {for (Map.EntryObject, Object entry : entriesToAddOnCommit.entrySet()) {// 将缓存数据写入到cache对象中 delegate.putObject(entry.getKey(), entry.getValue());}for (Object entry : entriesMissedInCache) {if (!entriesToAddOnCommit.containsKey(entry)) {delegate.putObject(entry, null);}}}
}解析注册部分
XMLMapperBuilder解析MapperStatement并放入到Configuration中
XMLMapperBuilder#configurationElement业务逻辑处理public class XMLMapperBuilder{private void configurationElement(XNode context) {try {String namespace context.getStringAttribute(namespace);if (namespace null || namespace.isEmpty()) {throw new BuilderException(Mappers namespace cannot be empty);}builderAssistant.setCurrentNamespace(namespace);cacheRefElement(context.evalNode(cache-ref));// 1. 解析XXXMapper.xml文件中的cache标签并调用builderAssistant.useNewCache构建Cache实例cacheElement(context.evalNode(cache));parameterMapElement(context.evalNodes(/mapper/parameterMap));resultMapElements(context.evalNodes(/mapper/resultMap));sqlElement(context.evalNodes(/mapper/sql));// 2. 构建Statement对象buildStatementFromContext(context.evalNodes(select|insert|update|delete));} catch (Exception e) {throw new BuilderException(Error parsing Mapper XML. The XML location is resource . Cause: e, e);}} private void buildStatementFromContext(ListXNode list, String requiredDatabaseId) {for (XNode context : list) {final XMLStatementBuilder statementParser new XMLStatementBuilder(configuration, builderAssistant, context, requiredDatabaseId);// 构建Statement对象statementParser.parseStatementNode();}}
}XMLMapperBuilder#cacheElement 展开细节
MapperBuilderAssistant#useNewCache构建Cache实例并添加到Configuration中缓存public class MapperBuilderAssistant{public Cache useNewCache(Class? extends Cache typeClass, Class? extends Cache evictionClass, Long flushInterval,Integer size, boolean readWrite, boolean blocking, Properties props) {Cache cache new CacheBuilder(currentNamespace).implementation(valueOrDefault(typeClass, PerpetualCache.class)).addDecorator(valueOrDefault(evictionClass, LruCache.class)).clearInterval(flushInterval).size(size).readWrite(readWrite).blocking(blocking).properties(props).build();configuration.addCache(cache);// 将cache实例赋值给MapperBuilderAssistant对象的 currentCache 属性currentCache cache;return cache;}
}XMLStatementBuilder#parseStatementNode 展开细节
XMLStatementBuilder#parseStatementNode调用builderAssistant.addMappedStatement实例化MapperStatement对象public class XMLStatementBuilder extends BaseBuilder {public void parseStatementNode() {// 省略部分代码 builderAssistant.addMappedStatement(id, sqlSource, statementType, sqlCommandType, fetchSize, timeout, parameterMap,parameterTypeClass, resultMap, resultTypeClass, resultSetTypeEnum, flushCache, useCache, resultOrdered,keyGenerator, keyProperty, keyColumn, databaseId, langDriver, resultSets, dirtySelect);}
}MapperBuilderAssistant#addMappedStatementpublic class MapperBuilderAssistant extends BaseBuilder {public MappedStatement addMappedStatement(String id, SqlSource sqlSource, StatementType statementType,SqlCommandType sqlCommandType, Integer fetchSize, Integer timeout, String parameterMap, Class? parameterType,String resultMap, Class? resultType, ResultSetType resultSetType, boolean flushCache, boolean useCache,boolean resultOrdered, KeyGenerator keyGenerator, String keyProperty, String keyColumn, String databaseId,LanguageDriver lang, String resultSets, boolean dirtySelect) {id applyCurrentNamespace(id, false);MappedStatement.Builder statementBuilder new MappedStatement.Builder(configuration, id, sqlSource, sqlCommandType).resource(resource).fetchSize(fetchSize).timeout(timeout).statementType(statementType).keyGenerator(keyGenerator).keyProperty(keyProperty).keyColumn(keyColumn).databaseId(databaseId).lang(lang).resultOrdered(resultOrdered).resultSets(resultSets).resultMaps(getStatementResultMaps(resultMap, resultType, id)).resultSetType(resultSetType).flushCacheRequired(flushCache).useCache(useCache)//1. 将MapperBuilderAssistant对象的 currentCache 属性放入到cache字段中.cache(currentCache).dirtySelect(dirtySelect);ParameterMap statementParameterMap getStatementParameterMap(parameterMap, parameterType, id);if (statementParameterMap ! null) {statementBuilder.parameterMap(statementParameterMap);}MappedStatement statement statementBuilder.build();configuration.addMappedStatement(statement);return statement;}
}
