Spring+Hibernate框架下MySql读写分离，主从数据库配置

介绍下mysql数据库读写分离在spring,hibernate框架下的配置。
1.mysql连接配置文件jdbc.properties 
master.*.*表示主数据库连接参数，负责增，删，改； 
slave.*.*表示从数据库连接参数，只负责读取； 

jdbc.properties 

 master.jdbc.driverClassName=com.mysql.jdbc.Driver
 master.jdbc.url=********
 master.jdbc.username=********
 master.jdbc.password=********

 slave.jdbc.driverClassName=com.mysql.jdbc.Driver
 slave.jdbc.url=********
 slave.jdbc.username=********
 slave.jdbc.password=********

把**改成你所需的连接参数； 

2.配置AOP切面类 DataSourceAdvice.java 

 import java.lang.reflect.Method;
 import org.springframework.aop.AfterReturningAdvice;
 import org.springframework.aop.MethodBeforeAdvice;
 import org.springframework.aop.ThrowsAdvice;

 import com.company.datasource.DataSourceSwitcher;

 public class DataSourceAdvice implements MethodBeforeAdvice, AfterReturningAdvice, ThrowsAdvice {
     // service方法执行之前被调用
     public void before(Method method, Object[] args, Object target) throws Throwable {
         System.out.println("切入点: " + target.getClass().getName() + "类中" + method.getName() + "方法");
         if(method.getName().startsWith("add")
             || method.getName().startsWith("create")
             || method.getName().startsWith("save")
             || method.getName().startsWith("edit")
             || method.getName().startsWith("update")
             || method.getName().startsWith("delete")
             || method.getName().startsWith("remove")){
             System.out.println("切换到: master");
             DataSourceSwitcher.setMaster();
         }
         else  {
             System.out.println("切换到: slave");
             DataSourceSwitcher.setSlave();
         }
     }

     // service方法执行完之后被调用
     public void afterReturning(Object arg0, Method method, Object[] args, Object target) throws Throwable {
     }

     // 抛出Exception之后被调用
     public void afterThrowing(Method method, Object[] args, Object target, Exception ex) throws Throwable {
         DataSourceSwitcher.setSlave();
         System.out.println("出现异常,切换到: slave");
     }

 }

数据源选择类 DataSourceSwitcher.java 

 package com.company.datasource;
 import org.springframework.util.Assert;

 public class DataSourceSwitcher {
     @SuppressWarnings("rawtypes")
     private static final ThreadLocal contextHolder = new ThreadLocal();

     @SuppressWarnings("unchecked")
     public static void setDataSource(String dataSource) {
         Assert.notNull(dataSource, "dataSource cannot be null");
         contextHolder.set(dataSource);
     }

     public static void setMaster(){
         clearDataSource();
     }

     public static void setSlave() {
         setDataSource("slave");
     }

     public static String getDataSource() {
         return (String) contextHolder.get();
     }

     public static void clearDataSource() {
         contextHolder.remove();
     }
 }

DynamicDataSource.java数据源动态切换类 

 package com.company.datasource;

 import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

 public class DynamicDataSource extends AbstractRoutingDataSource {

     @Override
     protected Object determineCurrentLookupKey() {
         return DataSourceSwitcher.getDataSource();
     }

 }

下面配置spring applicationContext.xml文件 

 xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
     xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context"
     xsi:schemaLocation="
         http://www.springframework.org/schema/beans
         http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
         http://www.springframework.org/schema/tx
         http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
         http://www.springframework.org/schema/aop
         http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
         http://www.springframework.org/schema/context
         http://www.springframework.org/schema/context/spring-context-3.0.xsd">

     <context:annotation-config />

     <context:component-scan base-package="cn.com.company.dao.*" />
     <context:component-scan base-package="cn.com.company.service.*" />
     <context:component-scan base-package="cn.com.company.action" />


     <bean id="propertyConfigurer"
         class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
         <property name="locations">
             <list>
                 <value>classpath:jdbc.propertiesvalue>
             list>
         property>
     bean>

     <bean id="parentDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
         //***c3p0配置
     bean>

     <bean id="masterDataSource" parent="parentDataSource">
         <property name="driverClass" value="${master.jdbc.driverClassName}" />
         <property name="jdbcUrl" value="${master.jdbc.url}" />
         <property name="user" value="${master.jdbc.username}" />
         <property name="password" value="${master.jdbc.password}" />
     bean>

     <bean id="slaveDataSource" parent="parentDataSource">
         <property name="driverClass" value="${slave.jdbc.driverClassName}" />
         <property name="jdbcUrl" value="${slave.jdbc.url}" />
         <property name="user" value="${slave.jdbc.username}" />
         <property name="password" value="${slave.jdbc.password}" />
     bean>

     <bean id="dataSource" class="com.company.datasource.DynamicDataSource">
         <property name="targetDataSources">
             <map key-type="java.lang.String">
                 <entry key="slave" value-ref="slaveDataSource" />
             map>
         property>
         <property name="defaultTargetDataSource" ref="masterDataSource" />
     bean>


     <bean id="sessionFactory"
         class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
         <property name="dataSource" ref="dataSource">property>
         <property name="packagesToScan" value="cn.com.company.entity" />
         <property name="hibernateProperties">
             <props>

                 <prop>//***hibernate一些参数这里不写了prop>
             props>
         property>
     bean>


     <bean id="dataSourceAdvice" class="com.company.aop.DataSourceAdvice" />
     <aop:config>
         <aop:advisor
             pointcut="execution(* cn.com.company.service..*Service.*(..))"
             advice-ref="dataSourceAdvice" />
     aop:config>


     <bean id="transactionManager"
         class="org.springframework.orm.hibernate3.HibernateTransactionManager">
         <property name="sessionFactory">
             <ref bean="sessionFactory" />
         property>
     bean>

     <tx:advice id="txAdvice" transaction-manager="transactionManager">
         <tx:attributes>

             <tx:method name="add*" propagation="REQUIRED" />
             <tx:method name="create*" propagation="REQUIRED" />
             <tx:method name="save*" propagation="REQUIRED" />
             <tx:method name="edit*" propagation="REQUIRED" />
             <tx:method name="update*" propagation="REQUIRED" />
             <tx:method name="delete*" propagation="REQUIRED" />
             <tx:method name="remove*" propagation="REQUIRED" />

             <tx:method name="loadByUsername*" propagation="SUPPORTS" read-only="true" />

             <tx:method name="*" propagation="SUPPORTS" read-only="true" />
         tx:attributes>
     tx:advice>

     <aop:config>
         <aop:advisor
             pointcut="execution(* cn.com.company.service..*Service.*(..))"
             advice-ref="txAdvice" />
         <aop:advisor
             pointcut="execution(* cn.com.company.service..*ServiceImpl.*(..))"
             advice-ref="txAdvice" />
     aop:config>


 beans>

！注 applicationContenxt.xml中 
 
 
 
pointcut="execution(* cn.com.company.service..*Service.*(..))" 
advice-ref="dataSourceAdvice" /> 
 
一定要配置在事务AOP之上