SpringMVC Mybatis配置多个数据源并切换代码详解

  <bean id="dataSourceTargetA" class="com.mchange.v2.c3p0.ComboPooledDataSource"
    destroy-method="close" scope="singleton">
    <property name="driverClass" value="${jdbc.a.driverClassName}" />
    <property name="jdbcUrl" value="${jdbc.a.url}" />
    <property name="user" value="${jdbc.a.username}" />
    <property name="password" value="${jdbc.a.password}" />
    <!--当连接池中的连接耗尽的时候c3p0一次同时获取的连接数。Default: 3 -->
    <property name="acquireIncrement" value="${c3p0.acquireIncrement}"></property>
    <!--初始化时获取三个连接，取值应在minPoolSize与maxPoolSize之间。Default: 3 -->
    <property name="initialPoolSize" value="${c3p0.initialPoolSize}"></property>
    <!--最大空闲时间,60秒内未使用则连接被丢弃。若为0则永不丢弃。Default: 0 -->
    <property name="maxIdleTime" value="${c3p0.maxIdleTime}"></property>
    <!--连接池中保留的最大连接数。Default: 15 -->
    <property name="maxPoolSize" value="${c3p0.maxPoolSize}"></property>
    <property name="minPoolSize" value="${c3p0.minPoolSize}"></property>
    <!--两次连接中间隔时间，单位毫秒。Default: 1000 -->
    <property name="acquireRetryDelay" value="1000"></property>
    <!--定义在从数据库获取新连接失败后重复尝试的次数。Default: 30 -->
    <property name="acquireRetryAttempts" value="60"></property>
    <!--获取连接失败将会引起所有等待连接池来获取连接的线程抛出异常。但是数据源仍有效保留，并在下次调用getConnection()的时候继续尝试获取连接。如果设为true，那么在尝试获取连接失败后该数据源将申明已断开并永久关闭。Default:
      false -->
    <property name="breakAfterAcquireFailure" value="false"></property>
  </bean>

  <bean id="dataSourceTargetB" class="com.mchange.v2.c3p0.ComboPooledDataSource"
     destroy-method="close" scope="singleton">
    <property name="driverClass" value="${jdbc.b.driverClassName}" />
    <property name="jdbcUrl" value="${jdbc.b.url}" />
    <property name="user" value="${jdbc.b.username}" />
    <property name="password" value="${jdbc.b.password}" />
    <!--当连接池中的连接耗尽的时候c3p0一次同时获取的连接数。Default: 3 -->
    <property name="acquireIncrement" value="${c3p0.acquireIncrement}"></property>
    <!--初始化时获取三个连接，取值应在minPoolSize与maxPoolSize之间。Default: 3 -->
    <property name="initialPoolSize" value="${c3p0.initialPoolSize}"></property>
    <!--最大空闲时间,60秒内未使用则连接被丢弃。若为0则永不丢弃。Default: 0 -->
    <property name="maxIdleTime" value="${c3p0.maxIdleTime}"></property>
    <!--连接池中保留的最大连接数。Default: 15 -->
    <property name="maxPoolSize" value="${c3p0.maxPoolSize}"></property>
    <property name="minPoolSize" value="${c3p0.minPoolSize}"></property>
    <!--两次连接中间隔时间，单位毫秒。Default: 1000 -->
    <property name="acquireRetryDelay" value="1000"></property>
    <!--定义在从数据库获取新连接失败后重复尝试的次数。Default: 30 -->
    <property name="acquireRetryAttempts" value="60"></property>
    <!--获取连接失败将会引起所有等待连接池来获取连接的线程抛出异常。但是数据源仍有效保留，并在下次调用getConnection()的时候继续尝试获取连接。如果设为true，那么在尝试获取连接失败后该数据源将申明已断开并永久关闭。Default:
      false -->
    <property name="breakAfterAcquireFailure" value="false"></property>
  </bean>
  <!-- 动态数据源 -->
  <bean id="dynamicDataSource" class="com.test.util.DynamicDataSource" >
    <property name="targetDataSources">
      <map key-type="java.lang.String">
        <entry value-ref="dataSourceTargetA" key="dataSourceTargetA"></entry>
        <entry value-ref="dataSourceTargetB" key="dataSourceTargetB"></entry>
      </map>
    </property>
    <property name="defaultTargetDataSource" ref="dataSourceTargetA" >
    </property>
  </bean>
  

  <bean id="txManager"
    class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dynamicDataSource" />
  </bean>
  

  <!-- MyBatis ORM operation class -->
  <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="dynamicDataSource" />
    <property name="mapperLocations">
      <list>
        <value>classpath*:com/test/**/*Mapper.xml</value>
      </list>
    </property>
    <property name="configLocation" value="classpath:provider-sql-map-config.xml" />
  </bean>

package com.test.util;
import com.test.util.CustomerContextHolder;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

/**
 * 动态数据源管理类
 *
 */
public class DynamicDataSource extends AbstractRoutingDataSource {

  @Override
  protected Object determineCurrentLookupKey() {
    return CustomerContextHolder.getCustomerType();
  }
}

package com.test.util;
/**
 * 数据源切换类
 *
 */
public class CustomerContextHolder {
  public static final String DATA_SOURCE_DEFAULT = "dataSourceTargetA";
  public static final String DATA_SOURCE_B = "dataSourceTargetB";
  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();
  }
}

/**
   * 订单列表查询，查询B数据源
   *
   * @param request
   * @return
   */
  @RequestMapping(value = "/list")
  public String list(HttpServletRequest request, Integer cId) {
    //设置数据源B
    CustomerContextHolder.setCustomerType(CustomerContextHolder.DATA_SOURCE_B);
    List<Order> orderList = salaryBillService.getSalaryOrderByOrgId(cId);
    request.setAttribute("orderList", orderList);
    //切换回默认数据源A
    CustomerContextHolder.setCustomerType(CustomerContextHolder.DATA_SOURCE_DEFAULT);
    return "/jsp/order";
  }