spring多數(shù)據(jù)源配置

項(xiàng)目中我們經(jīng)常會(huì)遇到多數(shù)據(jù)源的問題，尤其是數(shù)據(jù)同步或定時(shí)任務(wù)等項(xiàng)目更是如此。多數(shù)據(jù)源讓人最頭痛的，不是配置多個(gè)數(shù)據(jù)源，而是如何能靈活動(dòng)態(tài)的切換數(shù)據(jù)源。例如在一個(gè)spring和hibernate的框架的項(xiàng)目中，我們?cè)趕pring配置中往往是配置一個(gè)dataSource來連接數(shù)據(jù)庫，然后綁定給sessionFactory，在dao層代碼中再指定sessionFactory來進(jìn)行數(shù)據(jù)庫操作。

正如上圖所示，每一塊都是指定綁死的，如果是多個(gè)數(shù)據(jù)源，也只能是下圖中那種方式。

可看出在Dao層代碼中寫死了兩個(gè)SessionFactory，這樣日后如果再多一個(gè)數(shù)據(jù)源，還要改代碼添加一個(gè)SessionFactory，顯然這并不符合開閉原則。

那么正確的做法應(yīng)該是

代碼如下：

1. applicationContext.xml

<?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:cache="http://www.springframework.org/schema/cache"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:jee="http://www.springframework.org/schema/jee"

xmlns:jms="http://www.springframework.org/schema/jms" xmlns:lang="http://www.springframework.org/schema/lang"

xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:oxm="http://www.springframework.org/schema/oxm"

xmlns:p="http://www.springframework.org/schema/p" xmlns:task="http://www.springframework.org/schema/task"

xmlns:tx="http://www.springframework.org/schema/tx" xmlns:util="http://www.springframework.org/schema/util"

xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd?

http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd?

? http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache-3.1.xsd?

? ? http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd?

? ? http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.1.xsd?

? ? http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.1.xsd?

? ? http://www.springframework.org/schema/jms http://www.springframework.org/schema/jms/spring-jms-3.1.xsd?

? http://www.springframework.org/schema/lang http://www.springframework.org/schema/lang/spring-lang-3.1.xsd?

? http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd?

? http://www.springframework.org/schema/oxm http://www.springframework.org/schema/oxm/spring-oxm-3.1.xsd?

http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.1.xsd?

? ? http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd?

? ? http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsd">

<context:annotation-config />

<context:component-scan base-package="com"></context:component-scan>

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

<property name="locations">

<list>

<value>classpath:com/resource/config.properties</value>

</list>

</property>

</bean>

<bean id="dataSourceOne" class="com.mchange.v2.c3p0.ComboPooledDataSource"

destroy-method="close">

<property name="driverClass" value="${dbOne.jdbc.driverClass}" />

<property name="jdbcUrl" value="${dbOne.jdbc.url}" />

<property name="user" value="${dbOne.jdbc.user}" />

<property name="password" value="${dbOne.jdbc.password}" />

<property name="initialPoolSize" value="${dbOne.jdbc.initialPoolSize}" />

<property name="minPoolSize" value="${dbOne.jdbc.minPoolSize}" />

<property name="maxPoolSize" value="${dbOne.jdbc.maxPoolSize}" />

</bean>

<bean id="dataSourceTwo" class="com.mchange.v2.c3p0.ComboPooledDataSource"

destroy-method="close">

<property name="driverClass" value="${dbTwo.jdbc.driverClass}" />

<property name="jdbcUrl" value="${dbTwo.jdbc.url}" />

<property name="user" value="${dbTwo.jdbc.user}" />

<property name="password" value="${dbTwo.jdbc.password}" />

<property name="initialPoolSize" value="${dbTwo.jdbc.initialPoolSize}" />

<property name="minPoolSize" value="${dbTwo.jdbc.minPoolSize}" />

<property name="maxPoolSize" value="${dbTwo.jdbc.maxPoolSize}" />

</bean>

<bean id="dynamicDataSource" class="com.core.DynamicDataSource">

<property name="targetDataSources">

<map key-type="java.lang.String">

<entry value-ref="dataSourceOne" key="dataSourceOne"></entry>

<entry value-ref="dataSourceTwo" key="dataSourceTwo"></entry>

</map>

</property>

<property name="defaultTargetDataSource" ref="dataSourceOne">

</property>

</bean>

<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">

<property name="dataSource" ref="dynamicDataSource" />

<property name="hibernateProperties">

<props>

<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>

<prop key="hibernate.current_session_context_class">org.springframework.orm.hibernate4.SpringSessionContext</prop>

<prop key="hibernate.show_sql">false</prop>

<prop key="hibernate.format_sql">true</prop>

<prop key="hbm2ddl.auto">create</prop>

</props>

</property>

<property name="packagesToScan">

<list>

<value>com.po</value>

</list>

</property>

</bean>

<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">

<property name="sessionFactory" ref="sessionFactory" />

</bean>

<aop:config>

<aop:pointcut id="transactionPointCut" expression="execution(* com.dao..*.*(..))" />

<aop:advisor advice-ref="txAdvice" pointcut-ref="transactionPointCut" />

</aop:config>

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

<tx:attributes>

<tx:method name="add*" propagation="REQUIRED" />

<tx:method name="save*" propagation="REQUIRED" />

<tx:method name="update*" propagation="REQUIRED" />

<tx:method name="delete*" propagation="REQUIRED" />

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

</tx:attributes>

</tx:advice>

<aop:config>

<aop:aspect id="dataSourceAspect" ref="dataSourceInterceptor">

<aop:pointcut id="daoOne" expression="execution(* com.dao.one.*.*(..))" />

<aop:pointcut id="daoTwo" expression="execution(* com.dao.two.*.*(..))" />

<aop:before pointcut-ref="daoOne" method="setdataSourceOne" />

<aop:before pointcut-ref="daoTwo" method="setdataSourceTwo" />

</aop:aspect>

</aop:config>

</beans>

2. DynamicDataSource.class

package com.core;

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

public class DynamicDataSource extends AbstractRoutingDataSource{

@Override

protected Object determineCurrentLookupKey() {

return DatabaseContextHolder.getCustomerType();

}

}

3. DatabaseContextHolder.class

package com.core;

public class DatabaseContextHolder {

private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();

public static void setCustomerType(String customerType) {

contextHolder.set(customerType);

}

public static String getCustomerType() {

return contextHolder.get();

}

public static void clearCustomerType() {

contextHolder.remove();

}

}

4. DataSourceInterceptor.class

package com.core;

import org.aspectj.lang.JoinPoint;

import org.springframework.stereotype.Component;

@Component

public class DataSourceInterceptor {

public void setdataSourceOne(JoinPoint jp) {

DatabaseContextHolder.setCustomerType("dataSourceOne");

}

public void setdataSourceTwo(JoinPoint jp) {

DatabaseContextHolder.setCustomerType("dataSourceTwo");

}

}

5. po實(shí)體類

package com.po;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.Id;

import javax.persistence.Table;

@Entity

@Table(name = "BTSF_BRAND", schema = "hotel")

public class Brand {

private String id;

private String names;

private String url;

@Id

@Column(name = "ID", unique = true, nullable = false, length = 10)

public String getId() {

return this.id;

}

public void setId(String id) {

this.id = id;

}

@Column(name = "NAMES", nullable = false, length = 50)

public String getNames() {

return this.names;

}

public void setNames(String names) {

this.names = names;

}

@Column(name = "URL", length = 200)

public String getUrl() {

return this.url;

}

public void setUrl(String url) {

this.url = url;

}

}

package com.po;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.Id;

import javax.persistence.Table;

@Entity

@Table(name = "CITY", schema = "car")

public class City {

private Integer id;

private String name;

@Id

@Column(name = "ID", unique = true, nullable = false)

public Integer getId() {

return id;

}

public void setId(Integer id) {

this.id = id;

}

@Column(name = "NAMES", nullable = false, length = 50)

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

}

6. BrandDaoImpl.class

package com.dao.one;

import java.util.List;

import javax.annotation.Resource;

import org.hibernate.Query;

import org.hibernate.SessionFactory;

import org.springframework.stereotype.Repository;

import com.po.Brand;

@Repository

public class BrandDaoImpl implements IBrandDao {

@Resource

protected SessionFactory sessionFactory;

@SuppressWarnings("unchecked")

@Override

public List<Brand> findAll() {

String hql = "from Brand";

Query query = sessionFactory.getCurrentSession().createQuery(hql);

return query.list();

}

}

7. CityDaoImpl.class

package com.dao.two;

import java.util.List;

import javax.annotation.Resource;

import org.hibernate.Query;

import org.hibernate.SessionFactory;

import org.springframework.stereotype.Repository;

import com.po.City;

@Repository

public class CityDaoImpl implements ICityDao {

@Resource

private SessionFactory sessionFactory;

@SuppressWarnings("unchecked")

@Override

public List<City> find() {

String hql = "from City";

Query query = sessionFactory.getCurrentSession().createQuery(hql);

return query.list();

}

}

8. DaoTest.class

package com.test;

import java.util.List;

import javax.annotation.Resource;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.springframework.test.context.ContextConfiguration;

import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import org.springframework.test.context.transaction.TransactionConfiguration;

import com.dao.one.IBrandDao;

import com.dao.two.ICityDao;

import com.po.Brand;

import com.po.City;

@RunWith(SpringJUnit4ClassRunner.class)

@ContextConfiguration(locations = "classpath:com/resource/applicationContext.xml")

@TransactionConfiguration(transactionManager = "transactionManager", defaultRollback = false)

public class DaoTest {

@Resource

private IBrandDao brandDao;

@Resource

private ICityDao cityDao;

@Test

public void testList() {

List<Brand> brands = brandDao.findAll();

System.out.println(brands.size());

List<City> cities = cityDao.find();

System.out.println(cities.size());

}

}

利用aop，達(dá)到動(dòng)態(tài)更改數(shù)據(jù)源的目的。當(dāng)需要增加數(shù)據(jù)源的時(shí)候，我們只需要在applicationContext配置文件中添加aop配置，新建個(gè)DataSourceInterceptor即可。而不需要更改任何代碼。

寫在最后：

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