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spring hibernate实现动态替换表名(分表)的方法

时间:2018-07-21 07:47来源:网络整理 作者:51自学网
1.概述 其实最简单的办法就是使用原生sql,如 session.createSQLQuery("sql"),或者使用jdbcTemplate。但是项目中已经使用了hql的方式查询,修改起来又累,风险又大!所以,必须找到一种比较好的

1.概述

其实最简单的办法就是使用原生sql,如 session.createSQLQuery("sql"),或者使用jdbcTemplate。但是项目中已经使用了hql的方式查询,修改起来又累,风险又大!所以,必须找到一种比较好的解决方案,实在不行再改写吧!经过3天的时间的研究,终于找到一种不错的方法,下面讲述之。

2.步骤

2.1 新建hibernate interceptor类

/** * Created by hdwang on 2017/8/7. * * hibernate拦截器:表名替换 */ public class AutoTableNameInterceptor extends EmptyInterceptor { private String srcName = StringUtils.EMPTY; //源表名 private String destName = StringUtils.EMPTY; // 目标表名 public AutoTableNameInterceptor() {} public AutoTableNameInterceptor(String srcName,String destName){ this.srcName = srcName; this.destName = destName; } @Override public String onPrepareStatement(String sql) { if(srcName.equals(StringUtils.EMPTY) || destName.equals(StringUtils.EMPTY)){ return sql; } sql = sql.replaceAll(srcName, destName); return sql; } }

这个interceptor会拦截所有数据库操作,在发送sql语句之前,替换掉其中的表名。

2.2 配置到sessionFactory去

先看一下sessionFactory是个啥东西。

<bean > <property ref="defaultDataSource"></property> <property> <list> <value>com.my.pay.task.entity</value> <value>com.my.pay.paycms.entity</value> <value>com.my.pay.data.entity.payincome</value> </list> </property> <property> <list> <value>classpath*:/hibernate/hibernate-sql.xml</value> </list> </property> <property> <props> <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop> <prop key="hibernate.show_sql">false</prop> <prop key="hibernate.format_sql">false</prop> <prop key="hibernate.hbm2ddl.auto">none</prop> <!-- 开启查询缓存 --> <prop key="hibernate.cache.use_query_cache">false</prop> <!-- 配置二级缓存 --> <prop key="hibernate.cache.use_second_level_cache">true</prop> <!-- 强制Hibernate以更人性化的格式将数据存入二级缓存 --> <prop key="hibernate.cache.use_structured_entries">true</prop> <!-- Hibernate将收集有助于性能调节的统计数据 --> <prop key="hibernate.generate_statistics">false</prop> <!-- 指定缓存配置文件位置 --> <prop key="hibernate.cache.provider_configuration_file_resource_path">/spring/ehcache.xml</prop> <prop key="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</prop> <prop key="hibernate.current_session_context_class">jta</prop> <prop key="hibernate.transaction.factory_class">org.hibernate.engine.transaction.internal.jta.CMTTransactionFactory</prop> <prop key="hibernate.transaction.manager_lookup_class">com.atomikos.icatch.jta.hibernate3.TransactionManagerLookup</prop> </props> </property> </bean>

public class LocalSessionFactoryBean extends HibernateExceptionTranslator implements FactoryBean<SessionFactory>, ResourceLoaderAware, InitializingBean, DisposableBean { private DataSource dataSource; private Resource[] configLocations; private String[] mappingResources; private Resource[] mappingLocations; private Resource[] cacheableMappingLocations; private Resource[] mappingJarLocations; private Resource[] mappingDirectoryLocations; private Interceptor entityInterceptor; private NamingStrategy namingStrategy; private Object jtaTransactionManager; private Object multiTenantConnectionProvider; private Object currentTenantIdentifierResolver; private RegionFactory cacheRegionFactory; private Properties hibernateProperties; private Class<?>[] annotatedClasses; private String[] annotatedPackages; private String[] packagesToScan; private ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver(); private Configuration configuration; private SessionFactory sessionFactory;

那其实呢,sessionFactory是LocalSessionFactoryBean对象的一个属性,这点可以在LocalSessionFactoryBean类中可以看到,至于bean的注入为何是class的属性而非class本身,那是因为它实现了 FactoryBean<SessionFactory> 接口。sessionFacotry是由LocalSessionFactoryBean对象配置后生成的。生成后将sessionFactory对象注入到了spring容器,且仅此一个而已,默认单例嘛。

我们对数据库的操作都是用session对象,它是由sessionFactory对象生成的。下面是sessionFactory对象的两个方法:

/** * Open a {@link Session}. * <p/> * JDBC {@link Connection connection(s} will be obtained from the * configured {@link org.hibernate.service.jdbc.connections.spi.ConnectionProvider} as needed * to perform requested work. * * @return The created session. * * @throws HibernateException Indicates a problem opening the session; pretty rare here. */ public Session openSession() throws HibernateException; /** * Obtains the current session. The definition of what exactly "current" * means controlled by the {@link org.hibernate.context.spi.CurrentSessionContext} impl configured * for use. * <p/> * Note that for backwards compatibility, if a {@link org.hibernate.context.spi.CurrentSessionContext} * is not configured but JTA is configured this will default to the {@link org.hibernate.context.internal.JTASessionContext} * impl. * * @return The current session. * * @throws HibernateException Indicates an issue locating a suitable current session. */ public Session getCurrentSession() throws HibernateException;

那我们的项目使用getCurrentSession()获取session对象的。

hibernate interceptor怎么配置呢?

LocalSessionFactoryBean对象的entityInterceptor属性可以配置,你可以在xml中配置它,加到sessionFactory这个bean的xml配置中去。

<property> <bean/> </property>

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