Spring整合多数据源实现动态切换的实例讲解

##########################MySQL#####################################
hibernate.dialect=org.hibernate.dialect.MySQLInnoDBDialect
connection.driver_class=com.mysql.jdbc.Driver
connection.url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8
connection.username=yahu
connection.password=123456

##########################Oracle#####################################
connection1.driver_class=oracle.jdbc.driver.OracleDriver
connection1.url=jdbc\:oracle\:thin\:@localhost\:1521/MEDB
connection1.username=yahu
connection1.password=123456

##########################Sql Server2008#####################################
connection2.driver_class=net.sourceforge.jtds.jdbc.Driver
connection2.url=jdbc:jtds:sqlserver://localhost:1433;DatabaseName=test
connection2.username=yahu
connection2.password=123456

<!-- 数据库连接池配置 -->
  <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
  <property name="driverClassName" value="${connection.driver_class}" />
  <property name="url" value="${connection.url}" />
  <property name="username" value="${connection.username}" />
  <property name="password" value="${connection.password}" />
  
  <property name="initialSize" value="5" />
  <property name="minIdle" value="1" /> 
  <property name="maxActive" value="200" />
  
  <!-- 配置获取连接等待超时的时间 -->
  <property name="maxWait" value="30000" />
  
  <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->
  <property name="timeBetweenEvictionRunsMillis" value="60000" />
  
  <!-- 配置一个连接在池中最小生存的时间，单位是毫秒 -->
  <property name="minEvictableIdleTimeMillis" value="300000" />
 </bean>
 
 <!-- Oracle -->
 <bean id="dataSource1" class="org.apache.commons.dbcp.BasicDataSource">
  <property name="driverClassName" value="${connection1.driver_class}" />
  <property name="url" value="${connection1.url}" />
  <property name="username" value="${connection1.username}" />
  <property name="password" value="${connection1.password}" />
 </bean>

 <!-- Sql server 2008 -->
 <bean id="dataSource2" class="org.apache.commons.dbcp.BasicDataSource">
  <property name="driverClassName" value="${connection2.driver_class}" />
  <property name="url" value="${connection2.url}" />
  <property name="username" value="${connection2.username}" />
  <property name="password" value="${connection2.password}" />
 </bean>
 
  <!-- 动态数据源 -->
  <bean id="dynamicDataSource" class="com.yahu.core.dao.DynamicDataSource"> 
  <!-- 通过key-value的形式来关联数据源 --> 
  <property name="targetDataSources"> 
   <map> 
    <entry value-ref="dataSource" key="datasource" /> 
    <entry value-ref="dataSource1" key="datasource1" />
    <entry value-ref="dataSource2" key="datasource2" />   
   </map> 
  </property> 
  <property name="defaultTargetDataSource" ref="dataSource" /> 
 </bean>

package com.yahu.core.dao;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

/*******************************************************************
 * @describe : 建立动态数据源类 必须继承AbstractRoutingDataSource
 ********************************************************************/
public class DynamicDataSource extends AbstractRoutingDataSource {
 //coverity 修改
 //private Log log = LogFactory.getLog(getClass());

 protected Object determineCurrentLookupKey() {
  String value = CustomerContextHolder.getCustomerType();
  //log.info(value);
  return value;
 }

}

package com.yahu.core.dao;

/*******************************************************************
 * @describe : 获得和设置上下文环境
 ********************************************************************/
public class CustomerContextHolder {

 /**
  * mysql
  */
 public static final String DATASOURCE = "datasource";

 /**
  * oracle
  */
 public static final String DATASOURCE_1 = "datasource1";
 
 /**
  * sql server
  */
 public static final String DATASOURCE_2 = "datasource2";

 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();
 }
}

CustomerContextHolder.setCustomerType(CustomerContextHolder.DATASOURCE);

CustomerContextHolder.clearCustomerType();