基于SSM框架配置多数据源

项目基于ssm + maven，通过注解可以实现自动切换数据源。

一、pom.xml

 <?xml version="1.0" encoding="UTF-8"?>

 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>

     <groupId>com.multipleDataSource</groupId>
     <artifactId>multipleDataSource</artifactId>
     <version>1.0-SNAPSHOT</version>
     <packaging>war</packaging>

     <name>multipleDataSource Maven Webapp</name>
     <!-- FIXME change it to the project's website -->
     <url>http://www.example.com</url>

     <properties>
         <org.springframework.version>4.2.4.RELEASE</org.springframework.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <maven.compiler.encoding>UTF-8</maven.compiler.encoding>
         <maven.compiler.source>1.7</maven.compiler.source>
         <maven.compiler.target>1.7</maven.compiler.target>
         <jackson.version>2.8.5</jackson.version>

         <org.mybatis.version>3.4.1</org.mybatis.version>
         <org.mybatis.spring.version>1.3.0</org.mybatis.spring.version>
     </properties>

     <dependencies>
         <dependency>
             <groupId>org.apache.tomcat</groupId>
             <artifactId>tomcat-servlet-api</artifactId>
             <version>7.0.64</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-core</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-expression</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-beans</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-aop</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-context</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-webmvc</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-oxm</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-jdbc</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-tx</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-web</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-test</artifactId>
             <version>${org.springframework.version}</version>
         </dependency>

         <dependency>
             <groupId>org.aspectj</groupId>
             <artifactId>aspectjweaver</artifactId>
             <version>1.7.3</version>
         </dependency>

         <dependency>
             <groupId>org.mybatis</groupId>
             <artifactId>mybatis-spring</artifactId>
             <version>${org.mybatis.spring.version}</version>
         </dependency>
         <dependency>
             <groupId>org.mybatis</groupId>
             <artifactId>mybatis</artifactId>
             <version>${org.mybatis.version}</version>
         </dependency>

         <dependency>
             <groupId>org.aspectj</groupId>
             <artifactId>aspectjrt</artifactId>
             <version>1.6.11</version>
         </dependency>

         <dependency>
             <groupId>org.codehaus.jackson</groupId>
             <artifactId>jackson-mapper-asl</artifactId>
             <version>1.9.12</version>
         </dependency>

         <dependency>
             <groupId>commons-dbcp</groupId>
             <artifactId>commons-dbcp</artifactId>
             <version>1.4</version>
             <!--<scope>runtime</scope>-->
         </dependency>

         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>
             <version>1.1.2</version>
             <scope>compile</scope>
         </dependency>
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-core</artifactId>
             <version>1.1.2</version>
             <scope>compile</scope>
         </dependency>

         <dependency>
             <groupId>mysql</groupId>
             <artifactId>mysql-connector-java</artifactId>
             <version>5.1.6</version>
         </dependency>

         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
             <version>20.0</version>
         </dependency>

         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
             <version>3.5</version>
         </dependency>

         <dependency>
             <groupId>commons-collections</groupId>
             <artifactId>commons-collections</artifactId>
             <version>3.2.1</version>
         </dependency>

         <dependency>
             <groupId>com</groupId>
             <artifactId>druid</artifactId>
             <version>1.0.9</version>
         </dependency>

         <dependency>
             <groupId>javax.servlet</groupId>
             <artifactId>jstl</artifactId>
             <version>1.2</version>
         </dependency>

         <dependency>
             <groupId>taglibs</groupId>
             <artifactId>standard</artifactId>
             <version>1.1.2</version>
         </dependency>

         <!-- jackson -->
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-core</artifactId>
             <version>${jackson.version}</version>
         </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
             <version>${jackson.version}</version>
         </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-annotations</artifactId>
             <version>${jackson.version}</version>
         </dependency>

         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.11</version>
             <scope>test</scope>
         </dependency>
     </dependencies>

     <build>
         <finalName>multipleDataSource</finalName>
         <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
             <plugins>
                 <plugin>
                     <artifactId>maven-clean-plugin</artifactId>
                     <version>3.0.0</version>
                 </plugin>
                 <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
                 <plugin>
                     <artifactId>maven-resources-plugin</artifactId>
                     <version>3.0.2</version>
                 </plugin>
                 <plugin>
                     <artifactId>maven-compiler-plugin</artifactId>
                     <version>3.7.0</version>
                 </plugin>
                 <plugin>
                     <artifactId>maven-surefire-plugin</artifactId>
                     <version>2.20.1</version>
                 </plugin>
                 <plugin>
                     <artifactId>maven-war-plugin</artifactId>
                     <version>3.2.0</version>
                 </plugin>
                 <plugin>
                     <artifactId>maven-install-plugin</artifactId>
                     <version>2.5.2</version>
                 </plugin>
                 <plugin>
                     <artifactId>maven-deploy-plugin</artifactId>
                     <version>2.8.2</version>
                 </plugin>
             </plugins>
         </pluginManagement>
     </build>
 </project>

二、web.xml

 <!DOCTYPE web-app PUBLIC
  "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
  "http://java.sun.com/dtd/web-app_2_3.dtd" >

 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xmlns="http://java.sun.com/xml/ns/javaee"
          xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
          id="WebApp_ID" version="2.5">
   <display-name>Archetype Created Web Application</display-name>

   <!--过滤器，转码用的  /* 拦截所有路径-->
   <filter>
     <filter-name>characterEncodingFilter</filter-name>
     <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
     <init-param>
       <param-name>encoding</param-name>
       <param-value>UTF-8</param-value>
     </init-param>
     <init-param>
       <param-name>forceEncoding</param-name>
       <param-value>true</param-value>
     </init-param>
   </filter>
   <filter-mapping>
     <filter-name>characterEncodingFilter</filter-name>
     <url-pattern>/*</url-pattern>
   </filter-mapping>

     <!--前端分发器-->
     <servlet>
         <servlet-name>dispatcherServlet</servlet-name>
         <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
         <!--扫描springMVC配置文件-->
         <init-param>
             <param-name>contextConfigLocation</param-name>
             <param-value>
                 classpath:ApplicationContext.xml
             </param-value>
         </init-param>
         <!--设置优先级最高级-->
         <load-on-startup>1</load-on-startup>
     </servlet>
     <servlet-mapping>
         <servlet-name>dispatcherServlet</servlet-name>
         <url-pattern>/</url-pattern>
     </servlet-mapping>
 </web-app>

三、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:context="http://www.springframework.org/schema/context"
        xmlns:tx="http://www.springframework.org/schema/tx"
        xmlns:aop="http://www.springframework.org/schema/aop" xmlns:mvc="http://www.springframework.org/schema/mvc"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-4.0.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

     <!--注解配置-->
     <context:annotation-config/>

     <mvc:annotation-driven >
         <mvc:message-converters>
             <bean class="org.springframework.http.converter.StringHttpMessageConverter"/>
             <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>
         </mvc:message-converters>
     </mvc:annotation-driven>

     <!--扫描controller和service层-->
     <context:component-scan base-package="com.multipleDataSource.controller,com.multipleDataSource.service" annotation-config="true"/>

     <!--<context:annotation-config/>-->
     <aop:aspectj-autoproxy/>

     <!-- jdbc.properties文件路径 -->
     <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
         <property name="locations">
             <list>
                 <value>classpath:jdbc.properties</value>

             </list>
         </property> <!--value="classpath:/com/ningpai/web/config/jdbc.properties" />-->
     </bean>

     <!-- 数据源的配置 -->
     <bean id="dataSource1" class="com.alibaba.druid.pool.DruidDataSource"
           init-method="init" destroy-method="close">
         <property name="driverClassName" value="${jdbc.driver}"/>
         <property name="url" value="${jdbc.url}"/>
         <property name="username" value="${jdbc.username}"/>
         <property name="password" value="${jdbc.password}"/>
     </bean>

     <!--第二个数据源-->
     <bean name="dataSource2" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
         <property name="driverClassName" value="${jdbc.driver_2}"/>
         <property name="url" value="${jdbc.url_2}"/>
         <property name="username" value="${jdbc.username_2}"/>
         <property name="password" value="${jdbc.password_2}"/>
     </bean>

     <!-- 下面的是切换数据库的自定义类 -->
     <bean id="multipleDataSource" class="com.multipleDataSource.common.DynamicDataSource">
         <property name="targetDataSources">
             <map key-type="java.lang.String">
                 <entry key="dataSource1" value-ref="dataSource1"></entry>
                 <entry key="dateSource2" value-ref="dataSource2"></entry>
             </map>
         </property>
         <property name="defaultTargetDataSource" ref="dataSource1"></property>
     </bean>

     <!--事务相关控制-->
     <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
         <property name="dataSource" ref="multipleDataSource"/>
     </bean>
     <!-- 使用@Transactional进行声明式事务管理需要声明下面这行 -->
     <tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="true" order="2"/>

     <!-- MyBatis sqlSessionFactory 配置 mybatis-->
     <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
         <property name="dataSource" ref="multipleDataSource"/>
         <property name="mapperLocations" value="classpath*:mapper/*Mapper.xml"/>
     </bean>
     <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
         <constructor-arg index="0" ref="sqlSessionFactory"/>
     </bean>

     <!-- JdbcTemplate使用动态数据源的配置 -->
     <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
         <property name="dataSource">
             <ref bean="multipleDataSource"/>
         </property>
     </bean>

     <bean name="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
         <property name="basePackage" value="com.multipleDataSource.dao"/>
     </bean>

     <!--前缀和后缀配置-->
     <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
         <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
         <property name="prefix" value="/WEB-INF/views/"/>
         <property name="suffix" value=".jsp"/>
     </bean>

     <!-- 激活自动代理功能 -->
     <aop:aspectj-autoproxy proxy-target-class="true"/>

     <bean id="dataSourceAspect" class="com.multipleDataSource.common.aspect.DataSourceAspect"/>

     <aop:config>
         <aop:aspect id="c" ref="dataSourceAspect">
             <aop:pointcut id="tx" expression="execution(* com.multipleDataSource.dao..*.*(..))"/>
             <aop:before pointcut-ref="tx" method="before"/>
         </aop:aspect>
     </aop:config>
 </beans>

四、jdbc.properties

 jdbc.url=jdbc:mysql://localhost:3306/user?useUnicode=true&characterEncoding=UTF-8&relaxAutoCommit=true&zeroDateTimeBehavior=convertToNull
 jdbc.username=root
 jdbc.password=123456
 jdbc.driver=com.mysql.jdbc.Driver

 jdbc.driver_2=com.mysql.jdbc.Driver
 jdbc.url_2=jdbc:mysql://localhost:3306/city?useUnicode=true&characterEncoding=UTF-8&relaxAutoCommit=true&zeroDateTimeBehavior=convertToNull
 jdbc.username_2=root
 jdbc.password_2=123456

五、自定义DynamicDataSource 类

　　实现自动切换数据源，通过自定义DataSource注解，切面管理。

1、数据源上下文 DataSourceContextHolder

 package com.multipleDataSource.common;

 /**
  * 数据源上下文类
  * @author zhongtao on 2018/5/5
  */
 public class DataSourceContextHolder {
     private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();

     public static void setDbType(String dbType) {
         contextHolder.set(dbType);
     }

     public static String getDbType() {
         return ((String) contextHolder.get());
     }

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

2、DynamicDataSource 类

 package com.multipleDataSource.common;

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

 /**
  * 动态转换数据源
  * @author zhongtao on 2018/5/5
  */
 public class DynamicDataSource extends AbstractRoutingDataSource {
     @Override
     protected Object determineCurrentLookupKey() {
         return DataSourceContextHolder.getDbType();
     }
 }

3、DataSource 注解类

 package com.multipleDataSource.annotation;

 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;

 /**
  * 注解类
  * @author zhongtao on 2018/5/7
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.METHOD)
 public @interface DataSource {
     String value();
 }

4、DataSourceAspect 切面管理

 package com.multipleDataSource.common.aspect;

 import com.multipleDataSource.annotation.DataSource;
 import com.multipleDataSource.common.DataSourceContextHolder;
 import org.aspectj.lang.JoinPoint;
 import org.aspectj.lang.annotation.Before;
 import org.aspectj.lang.reflect.MethodSignature;

 import java.lang.reflect.Method;

 /**
  * 数据源切面类
  *
  * @author zhongtao on 2018/5/7
  */
 public class DataSourceAspect {
     public void pointCut() {
     }

     @Before(value = "pointCut()")
     public void before(JoinPoint point) {
         //拦截的实体类
         Object target = point.getTarget();
         //拦截的方法名
         String methodName = point.getSignature().getName();
         //接口
         Class<?>[] interfaces = target.getClass().getInterfaces();
         //拦截的放置参数类型
         Class<?>[] parameterTypes = ((MethodSignature) point.getSignature()).getMethod().getParameterTypes();

         try {
             Method method = interfaces[0].getMethod(methodName, parameterTypes);
             if (method != null && method.isAnnotationPresent(DataSource.class)) {
                 DataSource data = method.getAnnotation(DataSource.class);
                 DataSourceContextHolder.setDbType(data.value());
             }
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 }

5、数据源类型

 package com.multipleDataSource.common;

 /**
  * 数据源类型 需要和ApplicationContext.xml中的multipleDataSource下的key相同
  * @author zhongtao on 2018/5/5
  */
 public class DataSourceType {
     public static final String MYSQL1 = "dataSource1";

     public static final String MYSQL2 = "dateSource2";
 }

六、pojo类

1、User类

 package com.multipleDataSource.pojo;

 /**
  * @author zhongtao on 2018/5/7
  */
 public class User {

     private Integer id;

     /**
      * 用户名
      */
     private String userName;

     /**
      * 描述
      */
     private String description;

     private City city;

     public Integer getId() {
         return id;
     }

     public void setId(Integer id) {
         this.id = id;
     }

     public String getUserName() {
         return userName;
     }

     public void setUserName(String userName) {
         this.userName = userName;
     }

     public String getDescription() {
         return description;
     }

     public void setDescription(String description) {
         this.description = description;
     }

     public City getCity() {
         return city;
     }

     public void setCity(City city) {
         this.city = city;
     }
 }

2、City类

 package com.multipleDataSource.pojo;

 /**
  * @author zhongtao on 2018/5/7
  */
 public class City {
     /**
      * 城市编号
      */
     private Long id;

     /**
      * 省份编号
      */
     private Long provinceId;

     /**
      * 城市名称
      */
     private String cityName;

     /**
      * 描述
      */
     private String description;

     public Long getId() {
         return id;
     }

     public void setId(Long id) {
         this.id = id;
     }

     public Long getProvinceId() {
         return provinceId;
     }

     public void setProvinceId(Long provinceId) {
         this.provinceId = provinceId;
     }

     public String getCityName() {
         return cityName;
     }

     public void setCityName(String cityName) {
         this.cityName = cityName;
     }

     public String getDescription() {
         return description;
     }

     public void setDescription(String description) {
         this.description = description;
     }
 }

3、ResultVo类

 package com.multipleDataSource.pojo;

 /**
  * @author zhongtao on 2018/5/7
  */
 public class ResultVo<T> {

     private boolean success = true;
     private String code ="0000";
     private String msg;
     private T data;

     public boolean isSuccess() {
         return success;
     }

     public void setSuccess(boolean success) {
         this.success = success;
     }

     public String getCode() {
         return code;
     }

     public void setCode(String code) {
         this.code = code;
     }

     public String getMsg() {
         return msg;
     }

     public void setMsg(String msg) {
         this.msg = msg;
     }

     public T getData() {
         return data;
     }

     public void setData(T data) {
         this.data = data;
     }
 }

七、controller层

1、UserController类

 package com.multipleDataSource.controller;

 import com.multipleDataSource.pojo.ResultVo;
 import com.multipleDataSource.pojo.User;
 import com.multipleDataSource.service.UserService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
 import org.springframework.util.StringUtils;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.servlet.ModelAndView;

 /**
  * @author zhongtao on 2018/5/7
  */
 @Controller
 public class UserController {

     @Autowired
     private UserService userService;

     /**
      * 获取数据
      * @param userName
      * @return
      */
     @RequestMapping(value = "/getData")
     @ResponseBody
     public ResultVo getName(@RequestParam(value = "userName") String userName) {
         ResultVo<Object> resultVo = new ResultVo<>();
         if (userName==null){
             resultVo.setMsg("用户名错误");
             resultVo.setCode("0001");
         }else {
             User user = userService.findByName(userName);
             if(!StringUtils.isEmpty(user)){
                 resultVo.setMsg("测试成功");
                 resultVo.setData(user);
             }
         }
         return resultVo;
     }
 }

八、service层

1、UserService层

 package com.multipleDataSource.service;

 import com.multipleDataSource.pojo.User;

 /**
  * 用户类接口
  * @author zhongtao on 2018/5/7
  */
 public interface UserService {

     /**
      * 根据用户名获取用户信息，包括从库的地址信息
      *
      * @param userName
      * @return
      */
     User findByName(String userName);
 }

2、UserServiceImpl

 package com.multipleDataSource.service.impl;

 import com.multipleDataSource.dao.CityDao;
 import com.multipleDataSource.dao.UserDao;
 import com.multipleDataSource.pojo.City;
 import com.multipleDataSource.pojo.User;
 import com.multipleDataSource.service.UserService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;

 /**
  * @author zhongtao on 2018/5/7
  */
 @Service
 public class UserServiceImpl implements UserService{
     @Autowired
     private UserDao userDao; // 数据源1

     @Autowired
     private CityDao cityDao; // 数据源2

     @Override
     public User findByName(String userName) {
         User user = userDao.findByName(userName);
         City city = cityDao.findByName("成都市");
         user.setCity(city);
         return user;
     }
 }

九、dao层

1、UserDao类

 package com.multipleDataSource.dao;

 import com.multipleDataSource.pojo.User;
 import org.apache.ibatis.annotations.Mapper;
 import org.apache.ibatis.annotations.Param;

 /**
  * @author zhongtao on 2018/5/7
  */
 @Mapper
 public interface UserDao {

     /**
      * 根据用户名获取用户信息 默认数据源不用加 DataSource标签
      *
      * @param userName
      * @return
      */
     User findByName(@Param("userName") String userName);
 }

2、CityDao类

 package com.multipleDataSource.dao;

 import com.multipleDataSource.annotation.DataSource;
 import com.multipleDataSource.common.DataSourceType;
 import com.multipleDataSource.pojo.City;
 import org.apache.ibatis.annotations.Mapper;
 import org.apache.ibatis.annotations.Param;

 /**
  * @author zhongtao on 2018/5/7
  */
 @Mapper
 public interface CityDao {
     /**
      * 根据城市名称，查询城市信息 需要加上 DataSource标签，自动切换数据源
      *
      * @param cityName 城市名
      */
     @DataSource(DataSourceType.MYSQL2)
     City findByName(@Param("cityName") String cityName);
 }

十、mapper文件

1、UserMapper.xml

 <?xml version="1.0" encoding="UTF-8" ?>
 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
         "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 <mapper namespace="com.multipleDataSource.dao.UserDao">
     <resultMap id="BaseResultMap" type="com.multipleDataSource.pojo.User">
         <result column="id" property="id" />
         <result column="user_name" property="userName" />
         <result column="description" property="description" />
     </resultMap>

     <parameterMap id="User" type="com.multipleDataSource.pojo.User"/>

     <sql id="Base_Column_List">
         id, user_name, description
     </sql>

     <select id="findByName" resultMap="BaseResultMap" parameterType="java.lang.String">
         select
         <include refid="Base_Column_List" />
         from user
         where user_name = #{userName}
     </select>
 </mapper>

2、CityMapper.xml

 <?xml version="1.0" encoding="UTF-8" ?>
 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 <mapper namespace="com.multipleDataSource.dao.CityDao">
     <resultMap id="BaseResultMap" type="com.multipleDataSource.pojo.City">
         <result column="id" property="id" />
         <result column="province_id" property="provinceId" />
         <result column="city_name" property="cityName" />
         <result column="description" property="description" />
     </resultMap>

     <parameterMap id="City" type="com.multipleDataSource.pojo.City"/>

     <sql id="Base_Column_List">
         id, province_id, city_name, description
     </sql>

     <select id="findByName" resultMap="BaseResultMap" parameterType="java.lang.String">
         select
         <include refid="Base_Column_List" />
         from city
         where city_name = #{cityName}
     </select>

 </mapper>

十一、测试

1、网址输入

2、结果显示