專案中有配置多資料來源的需求，查了一些資料最終實現，主要參考資料：

http://www.cnblogs.com/linjiqin/archive/2011/02/12/1952904.html

https://my.oschina.net/frankly/blog/27702

我用的是spring3 + jpa2 + hibernate4，配置方式與資料中略有不同，但是都大同小異，下面說一下過程和幾個我認為的關鍵點：

1.通常jpa專案會在classpath/META-INF目錄下有個persistence.xml配置檔案，我的專案沒有這個檔案，內容直接配到spring的配置檔案裡了，以下是spring配置檔案內容：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	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:task="http://www.springframework.org/schema/task"
	xsi:schemaLocation="
    http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/tx
    http://www.springframework.org/schema/tx/spring-tx.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd
    http://www.springframework.org/schema/aop
    http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">
	
	<!-- 使用annotation @Repository,@Service自動註冊bean, 並保證@Required、@Autowired的屬性被注入的包範圍 -->
    <context:component-scan base-package="com.cf" />
 

<!-- 資料來源1  -->
    <bean id="dataSource" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <!-- Connection Info   coding -->
        <property name="jdbcUrl" value="jdbc:mysql://192.168.199.162:3306/cf-db?autoreconect=true&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
        <property name="maximumPoolSize" value="10"/>
        <property name="maxLifetime" value="28700000" />
        <property name="poolName" value="cf-pool0"/>
    </bean>


	<!-- Jpa Entity Manager 配置 -->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="jpaVendorAdapter" ref="hibernateJpaVendorAdapter"/>
        <property name="packagesToScan">  <!-- 掃描對映類的包 -->
            <list>
                <value>com.cf.bus.core.*.domain</value>
                <value>com.cf.bus.additional.*.domain</value>
            </list>
        </property>
        <property name="jpaProperties">  <!-- 如果有persistence.xml可以配置在那裡  -->
            <props>
                <prop key="hibernate.show_sql">false</prop>
                <prop key="hibernate.format_sql">false</prop>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
                <prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>
              	<prop key="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</prop>

            </props>
        </property>
        <property name ="persistenceUnitName" value="unit1"/> <!-- 這個在java程式碼中注入的時候用到 ，如果有 persistence.xml也可配在那裡-->
    </bean>

	<bean id="hibernateJpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
    </bean>
    
	<bean id="txManager" class="org.springframework.orm.jpa.JpaTransactionManager">
		<property name="entityManagerFactory" ref="entityManagerFactory" />
	</bean>
	
	<tx:advice id="txAdvice" transaction-manager="txManager">
		<tx:attributes>
			<tx:method name="add*" propagation="REQUIRED" />
			<tx:method name="delete*" propagation="REQUIRED" />
			<tx:method name="update*" propagation="REQUIRED" />
			<tx:method name="*" propagation="REQUIRED" />
		</tx:attributes>
	</tx:advice>

	<aop:config>
		<aop:pointcut id="allManagerMethod"
			expression="execution(* com..service.*.*(..))" />
		<aop:advisor advice-ref="txAdvice" pointcut-ref="allManagerMethod" />
	</aop:config>












<!--  資料來源2   -->
    <bean id="dataSource2" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <!-- Connection Info   coding -->
        <property name="jdbcUrl" value="jdbc:mysql://192.168.199.162:3306/cf-rs?autoreconect=true&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
        <property name="maximumPoolSize" value="10"/>
        <property name="maxLifetime" value="28700000" />
        <property name="poolName" value="cf-pool2"/>
    </bean>

    <!-- Jpa Entity Manager 配置 -->
    <bean id="entityManagerFactory2" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource2"/>
        <property name="jpaVendorAdapter" ref="hibernateJpaVendorAdapter2"/>
        <property name="packagesToScan">  <!--  這裡要掃描另外的包，跟第一個資料來源的要區別開  -->
            <list>
                <value>com.cf.bus.core.rs.template.domain</value>
            </list>
        </property>
        <property name="jpaProperties">   <!-- 如果有persistence.xml可以配置在那裡  -->
            <props>
                <prop key="hibernate.show_sql">false</prop>
                <prop key="hibernate.format_sql">false</prop>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
                <prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>
                <prop key="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</prop>

            </props>
        </property>
        <property name ="persistenceUnitName" value="unit2"/>   <!-- 這裡是第二個資料來源為entityManager注入時用的 ，如果有 persistence.xml也可配在那裡  -->
    </bean>

    <bean id="hibernateJpaVendorAdapter2" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
    </bean>

<!-- 由於第二個資料來源不需要對資料庫做改的操作，所以沒有配置事務  -->



</beans>

兩個資料來源中有很多不同的地方，由於程式碼裡不能直接標顏色，所以只能靠自己觀察了，仔細看，spring配置完成，接下來是java程式碼。

2.在java中注入

a.資料來源1的注入

package com.cf.bus.common.dao.jpa;

import org.apache.log4j.Logger;
import org.hibernate.SQLQuery;
import org.hibernate.transform.Transformers;

import javax.annotation.Resource;
import javax.persistence.*;
import javax.persistence.criteria.*;
import java.io.Serializable;
import java.lang.reflect.Field;
import java.util.*;

public class BaseDaoImpl<T> implements BaseDao<T> {

	private static final Logger logger = Logger.getLogger(BaseDaoImpl.class);

	@PersistenceContext(unitName = "unit1")
	protected EntityManager em;
	@Resource(name = "entityManagerFactory")
	protected EntityManagerFactory emf;
 

.....   //業務程式碼

}

package com.cf.bus.core.rs.base.dao.jpa;


import org.apache.log4j.Logger;
import org.hibernate.SQLQuery;
import org.hibernate.transform.Transformers;

import javax.annotation.Resource;
import javax.persistence.*;
import javax.persistence.criteria.*;
import java.io.Serializable;
import java.lang.reflect.Field;
import java.util.*;

public class BaseDaoImpl<T> implements BaseDao<T> {

	private static final Logger logger = Logger.getLogger(BaseDaoImpl.class);

	@PersistenceContext(unitName = "unit2")
	protected EntityManager em;
	@Resource(name = "entityManagerFactory2")
	protected EntityManagerFactory emf;

......   //業務程式碼

}

由於眾所周知的原因，隱掉了一些包引用和修改了一些包名，請不要在意這些細節，並不影響本文討論的重點。

如果有問題歡迎一起交流！！