本文主要解决基于spring data jpa读写分离。
思想:在dataSource做路由,根据事务判断使用主从数据源。
背景:spring+spring data jpa(hibernate jpa)
首先是jpa配置,时间有限在原基础上该的,既有java配置也有xml配置,见谅。
先声明EntityManager
<!-- Jpa Entity Manager 配置 --> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="dataSource" ref="dataSource"/> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> <property name="showSql" value="false" /> <property name="generateDdl" value="true" /> <property name="database" value="MYSQL" /> </bean> </property> <property name="packagesToScan" value="com.lee"/> <property name="jpaProperties"> <props> <!-- 命名规则 My_NAME->MyName --> <prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop> </props> </property> </bean> <!-- 动态dataSource --> <bean id="dataSource" class="com.lee.spring.core.jpa.rws.RwDataSource"> <property name="targetDataSources"> <map key-type="java.lang.String"> <!-- write --> <entry key="master" value-ref="masterDataSource"/> <!-- read --> <entry key="slave" value-ref="slaveDataSource"/> </map> </property> <property name="defaultTargetDataSource" ref="masterDataSource"/> </bean> <!-- 主(写)数据源 --> <bean id="masterDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close"> <property name="driverClass" value="${jdbc.master.driver}" /> <property name="jdbcUrl" value="${jdbc.master.url}" /> <property name="user" value="${jdbc.master.username}" /> <property name="password" value="${jdbc.master.password}" /> <property name="maxPoolSize" value="30" /> <property name="minPoolSize" value="10" /> <property name="initialPoolSize" value="1" /> <property name="maxIdleTime" value="0" /> <property name="acquireIncrement" value="3" /> <property name="acquireRetryAttempts" value="30" /> <property name="checkoutTimeout" value="0" /> <property name="idleConnectionTestPeriod" value="60" /> </bean> <!-- 从(读)数据源 --> <bean id="slaveDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close"> <property name="driverClass" value="${jdbc.slave.driver}" /> <property name="jdbcUrl" value="${jdbc.slave.url}" /> <property name="user" value="${jdbc.slave.username}" /> <property name="password" value="${jdbc.slave.password}" /> <property name="maxPoolSize" value="30" /> <property name="minPoolSize" value="10" /> <property name="initialPoolSize" value="1" /> <property name="maxIdleTime" value="0" /> <property name="acquireIncrement" value="3" /> <property name="acquireRetryAttempts" value="30" /> <property name="checkoutTimeout" value="0" /> <property name="idleConnectionTestPeriod" value="60" /> </bean>
用java声明的jpa设置
import javax.annotation.Resource; import javax.persistence.EntityManagerFactory; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.PropertySource; import org.springframework.context.support.PropertySourcesPlaceholderConfigurer; import org.springframework.data.jpa.repository.config.EnableJpaRepositories; import org.springframework.transaction.annotation.EnableTransactionManagement; import com.lee.spring.core.jpa.rws.MyJpaTransactionManager; /** * spring-jpa设置 * @author lee * */ @Configuration @PropertySource("classpath:/application.properties") @EnableTransactionManagement @EnableJpaRepositories(basePackages = {"com.lee.**.dao"}) public class SpringDaoConfig { private static final Logger logger = LoggerFactory.getLogger(SpringDaoConfig.class); @Resource(name="entityManagerFactory") private EntityManagerFactory entityManagerFactory; /** * 描述 : 负责解析资源文件 * 这个类必须有,而且必须声明为static,否则不能正常解析 * @return */ @Bean public static PropertySourcesPlaceholderConfigurer placehodlerConfigurer() { logger.info("PropertySourcesPlaceholderConfigurer"); return new PropertySourcesPlaceholderConfigurer(); } @Bean(name="entityManagerFactory") public EntityManagerFactory entityManagerFactory() { return entityManagerFactory; } @Bean(name="transactionManager") public MyJpaTransactionManager transactionManager() { MyJpaTransactionManager transactionManager = new MyJpaTransactionManager(); transactionManager.setEntityManagerFactory(entityManagerFactory); return transactionManager; } }
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由上可以看出跟平常不同的有两点
- 自定义动态连接池RwDataSource
- 自定义事务管理器MyJpaTransactionManager
其中MyJpaTransactionManager主要作用在于判断事务类别。因为我是使用注解@Transactional来声明事务,所以该类做了如下调整
import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.orm.jpa.JpaTransactionManager; import org.springframework.transaction.TransactionDefinition; import org.springframework.transaction.support.DefaultTransactionStatus; @SuppressWarnings("serial") public class MyJpaTransactionManager extends JpaTransactionManager{ private static final Logger logger = LoggerFactory.getLogger(MyJpaTransactionManager.class); @Override protected void doBegin(Object transaction, TransactionDefinition definition) { if(definition.isReadOnly()){ RwDataSourceHolder.localSlave(); }else{ RwDataSourceHolder.localMaster(); } logger.info("jpa-transaction:begin-----now dataSource is ["+RwDataSourceHolder.getDataSouce()+"]"); super.doBegin(transaction, definition); } @Override protected void doCommit(DefaultTransactionStatus status) { logger.info("jpa-transaction:commit-----now dataSource is ["+RwDataSourceHolder.getDataSouce()+"]"); super.doCommit(status); } }
上面涉及到definition.isReadOnly()来判断我的注解声明,依此来决定使用哪个dataSource。
public class RwDataSourceHolder { public static final String MASTER = "master"; //主(写)连接池 public static final String SLAVE = "slave"; //从(读)连接池 public static final ThreadLocal<String> holder = new ThreadLocal<String>(); public static void localMaster() { holder.set(MASTER); } public static void localSlave() { holder.set(SLAVE); } public static String getDataSouce() { return holder.get(); } }
最后是RwDataSource,这个完全基于spring提供的AbstractRoutingDataSource
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource; public class RwDataSource extends AbstractRoutingDataSource { @Override protected Object determineCurrentLookupKey() { return RwDataSourceHolder.getDataSouce(); } }