SpringMvc+Mybatis多数据源切换

昨天经理让我写一个Springmvc连接多数据库的demo。第一次接触这个问题，所以就去网上找了相关资料。发现并不是很难实现，于是在自己之前写的一个登录注册demo上加上这个连接多数据源的部分做测试。我的实现目标是，在登录时查询数据库Ａ，登录成功跳转到下一个页面，而这个页面上显示的数据库是从数据库Ｂ拿的。

下面是代码部分：

首先在spring-mybatis.xml配置文件中配置第二个数据库

dataSourceA是原先配置好的第一个数据库。dataSourceB是现在添加的数据库，也是MySql，当然也可以是其他数据库。



接下来是配置切换数据源，这里默认的数据库是dataSourceA



我这里的两个数据库用的都是MySQL，一个是同事的，一个是本地的。如果是两个不同的数据库，改一下配置条件即可。spring-mybatis.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:context="http://www.springframework.org/schema/context"
xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:jee="http://www.springframework.org/schema/jee"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:util="http://www.springframework.org/schema/util"
xmlns:jpa="http://www.springframework.org/schema/data/jpa"
xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd">
<!-- 配置MyBatis -->
<bean id="dataSourceA"
class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass"
value="com.mysql.jdbc.Driver"/>
<property name="jdbcUrl"
value="jdbc:mysql://192.168.1.39:3306/doctor-nurse"/>
<property name="user"
value="admin"/>
<property name="password"
value="admin"/>
</bean>
<bean id="dataSourceB"
class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass"
value="com.mysql.jdbc.Driver"/>
<property name="jdbcUrl"
value="jdbc:mysql://localhost:3306/doctor-nurse"/>
<property name="user"
value="root"/>
<property name="password"
value="root"/>
</bean>
<bean id="dataSource" class="com.lonbon.hispitalcare.datasource.DynamicDataSource">
<property name="targetDataSources">
<map key-type="java.lang.String">
<entry value-ref="dataSourceA" key="dataSourceA"></entry>
<entry value-ref="dataSourceB" key="dataSourceB"></entry>
</map>
</property>
<property name="defaultTargetDataSource" ref="dataSourceA"></property>
</bean>
<!-- 配置SplSessionFactoryBean -->
<bean id="sqlSessionFactory"
class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource"
ref="dataSource"/>
<!-- mapper文件存储在
src/main/resources/mappers 文件夹 -->
<property name="mapperLocations"
value="classpath:mappers/*.xml"/>
</bean>

<bean id="mapperScanner"
class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="sqlSessionFactory"
ref="sqlSessionFactory"/>
<property name="basePackage"
value="com.lonbon.hispitalcare.dao"/>
</bean>

<!-- 配置视图解析器 -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/"/>
<property name="suffix" value=".jsp"/>
</bean>
<bean id="transactionManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
</bean>
</beans>

然后写一个切换数据源的类DynamicDataSource，继承AbstractRoutingDataSource

代码如下：

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

import java.sql.SQLFeatureNotSupportedException;
import java.util.logging.Logger;

/**
* Created by LB on 2017/6/14.
* 配置多数据源
*/
public class DynamicDataSource extends AbstractRoutingDataSource {
public static final String DATASOURCE_A = "dataSourceA";
public static final String DATASOURCE_B = "dataSourceB";
//本地线程，获取当前正在执行的currentThread
public static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();

public static void setCustomerType(String customerType) {
//把当前请求的参数，存入当前线程，这个参数是我们定义的DATASOURCE_A或者DATASOURCE_B
System.out.println("当前切换的数据源="+customerType);
contextHolder.set(customerType);
}
public static String getCustomerType() {

return contextHolder.get();
}

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

protected Object determineCurrentLookupKey() {
return getCustomerType();
}

public Logger getParentLogger() throws SQLFeatureNotSupportedException {
return null;
}
}

在哪里需要切换数据源，那就在哪个controller里添加

DynamicDataSource.setCustomerType(DynamicDataSource.DATASOURCE_A);即可



这样就实现了切换数据源的功能