1.在项目的applicationContext.xml中配置多个数据源

<bean id="dataSource1" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
	 <property name="driverClassName"><value>com.mysql.jdbc.Driver</value></property>
	<property name="url"><value>jdbc:mysql://localhost:3306/test</value></property>
	<property name="username"><value>root</value></property>
	<property name="password"><value>myadmin</value></property>
 </bean>
    
    <bean id="dataSource2" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
	 <property name="driverClassName"><value>com.mysql.jdbc.Driver</value></property>
	<property name="url"><value>jdbc:mysql://localhost:3306/test2</value></property>
	<property name="username"><value>root</value></property>
	<property name="password"><value>myadmin</value></property>
 </bean>

2.新建动态切换数据源的类DynamicDataSource.java

package com.springmvc.config;

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

public class DynamicDataSource extends AbstractRoutingDataSource {
	public static final String DATASOURCE1 = "dataSource1";  
    public static final String DATASOURCE2 = "dataSource2";  
    //----获取到当前正在执行的CurrentThread  
    public 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();  
    }  
	@Override
	protected Object determineCurrentLookupKey() {
        return getCustomerType();  
	}
}

 <bean id="dataSource" class="com.springmvc.config.DynamicDataSource">
        <property name="targetDataSources">
            <map key-type="java.lang.String">
                <entry value-ref="dataSource1" key="dataSource1"></entry>
                <entry value-ref="dataSource2" key="dataSource2"></entry>
            </map>
        </property>
       <!-- 默认使用数据源1 -->
        <property name="defaultTargetDataSource" ref="dataSource1"></property>
</bean>
 
 <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
	<property name="dataSource" ref="dataSource"></property>
</bean>

@RequestMapping("/findUsers")
@ResponseBody
    public  Map<String, Object> findUsers(HttpServletRequest request,HttpServletResponse resp){
			Map<String, Object> map = new HashMap<>();
			//切换到数据源2，下面一行即可切换
			DynamicDataSource.setCustomerType(DynamicDataSource.DATASOURCE2);
			List<Map<String, Object>> allUser = userDao.findAllUser();
			map.put("code", 100);
			map.put("message", "查询成功");
			map.put("list", allUser);
			return map;
    }