Spring 学习系列 -- Spring + Mybatis 从零开始配置多数据源访问

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SSH Mybatis

目的：

项目中以前有整合mybatis + spring操作数据库，但是以前都是单数据库，现需要实现mybatis访问多数据源，依旧使用spring调用mybatis。

通过注解的方式整合 spring + mybatis 多数据源，同时使两者能够执行事务操作

网上虽然也有类似的文章，但是或多或少有些问题。先将我的解决方法记录下来，以供参考。

步骤

导入相关的包

有2个数据库，分别是spring1 和 spring2

spring1 有表：teacher和数据

CREATE TABLE `teacher` (
  `iTeacherId` int(11) NOT NULL AUTO_INCREMENT,
  `sName` varchar(32) DEFAULT NULL,
  PRIMARY KEY (`iTeacherId`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

INSERT INTO `teacher` VALUES (1, 'teacher1');
INSERT INTO `teacher` VALUES (2, 'teacher2');

spring2有表：

CREATE TABLE `student` (
  `iStudentId` int(11) NOT NULL AUTO_INCREMENT,
  `sName` varchar(32) DEFAULT NULL,
  `iClass` int(11) DEFAULT NULL COMMENT '班级',
  PRIMARY KEY (`iStudentId`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;
INSERT INTO `student` VALUES (1, 'student1', 1);
INSERT INTO `student` VALUES (2, 'student2', 2);
INSERT INTO `student` VALUES (3, 'student3', 2);

功能：同时查询spring1.teacher和spring2.student 且支持事务操作

建立工程如下：

各个包说明：

com.my.teacher.pojo，com.my.student.pojo：和表结构一一对应的pojo类

Teacher类：

public class Teacher {
	private Integer iTeacherId;
	private String sName;
        ....
}

Student类：

public class Student {
	private Integer iStudentId;
	private String sName;
	private Integer iClass;
        ...
}

com.my.student.mapper，com.my.teacher.mapper：mybatis的Mapper类，每个mapper都必须有一个同名的mapper.xml

StudentMapper类和对应的mapper.xml

public interface StudentMapper {
	List<Student> querys(Map<String,Object> map);
}

<?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.my.student.mapper.StudentMapper" >
  <!-- resultMap  -->
  <resultMap id="ResultMap" type="Student" >
    <id column="iStudentId" property="iStudentId" jdbcType="INTEGER" />
    <result column="sName" property="sName" jdbcType="VARCHAR" />
    <result column="iClass" property="iClass" jdbcType="INTEGER" />
  </resultMap>
 
  <!-- querys  -->
  <select id="querys" resultMap="ResultMap" parameterType="map" >
    select * from student
  </select>
 
</mapper>

TeacherMapper类和对应的mapper.xml

public interface TeacherMapper {
	List<Teacher> querys(Map<String,Object> map);
}

<?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.my.teacher.mapper.TeacherMapper" >
  <!-- resultMap  -->
  <resultMap id="ResultMap" type="Teacher" >
    <id column="iTeacherId" property="iTeacherId" jdbcType="INTEGER" />
    <result column="sName" property="sName" jdbcType="VARCHAR" />
  </resultMap>
 
  <!-- querys  -->
  <select id="querys" resultMap="ResultMap" parameterType="map" >
    select * from teacher
  </select>
 
</mapper>

com.my.student.dao，com.my.student.dao.imp：调用mapper，逐个获取student、teacher记录

public interface Dao {
	public void printAll();
	public void printStudent();
	public void printTeacher();
}

@Component
@Transactional
public class DaoImp implements Dao {
	@Resource private StudentMapper studentMapper;
	@Resource private TeacherMapper teacherMapper;
	
	
	@Override
	public void printAll() {
		// TODO Auto-generated method stub
		List<Student> l = this.studentMapper.querys(new HashMap<String,Object>());
		for(Student o : l){
			System.out.println(o);
		}
		
		List<Teacher> l2 = this.teacherMapper.querys(new HashMap<String,Object>());
		for(Teacher o : l2){
			System.out.println(o);
		}
	}
	
	@Override
	public void printStudent() {
		// TODO Auto-generated method stub
		List<Student> l = this.studentMapper.querys(new HashMap<String,Object>());
		for(Student o : l){
			System.out.println(o);
		}
	}
	
	@Override
	public void printTeacher() {
 
		
		List<Teacher> l2 = this.teacherMapper.querys(new HashMap<String,Object>());
		for(Teacher o : l2){
			System.out.println(o);
		}
	}

}

com.my.student.dao.imp.test：测试dao类，代码略
resource：配置类，这里是重点介绍部分

main.properties：属性配置文件，把一些易变的属性配置到这个文件中，比配置到spring的配置文件中，要易于维护。

# ALL database are same
main.db.sIp=127.0.0.1
main.db.sPort=3306
main.db.sUsername=mysql
main.db.sPassword=password

mybatis_student.xml：spring2的mybatis配置xml

<configuration>   
    <settings>   
        <!-- changes from the defaults for testing -->   
        <setting name="cacheEnabled" value="false" />   
        <setting name="useGeneratedKeys" value="true" />   
        <setting name="defaultExecutorType" value="REUSE" /> 
    </settings>    
  
    <typeAliases>
        <!-- 类重命名 -->
		<typeAlias type="com.my.student.pojo.Student" alias="Student"/>
    </typeAliases>
     
</configuration>

mybatis_teacher.xml：spring1的mybatis配置xml 和 mybatis_student相似

<configuration>   
    <settings>   
        <!-- changes from the defaults for testing -->   
        <setting name="cacheEnabled" value="false" />   
        <setting name="useGeneratedKeys" value="true" />   
        <setting name="defaultExecutorType" value="REUSE" /> 
    </settings>    
  
    <typeAliases>
		<!-- 类重命名 -->
		<typeAlias type="com.my.teacher.pojo.Teacher" alias="Teacher"/>
    </typeAliases>
     
</configuration>

spring_student.xml：spring2的spring配置文件(具体说明见xml里的注释)

<?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:aop="http://www.springframework.org/schema/aop"
     xmlns:tx="http://www.springframework.org/schema/tx"
     xmlns:context="http://www.springframework.org/schema/context"
     xsi:schemaLocation="
     http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
     http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
     http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
     http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">

  <!-- 开启注释扫描   --> 
  <context:annotation-config />
  <!-- 包扫描 -->
  <context:component-scan base-package="
  		com.my.student.dao
  	"/>
 
  <!-- 加载外部属性配置文件 -->
  <context:property-placeholder location="classpath:resource/main.properties" />
 
  <!-- 多个数据源的 DataSource名称不能相等 -->
  <bean id="studentDataSource" destroy-method="close"
    class="org.apache.commons.dbcp.BasicDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://${main.db.sIp}:${main.db.sPort}/spring2" />  
    <property name="username" value="${main.db.sUsername}" />
    <property name="password" value="${main.db.sPassword}" />
    <property name="initialSize" value="20"/>  
    <property name="maxActive" value="200"/>  
    <property name="maxIdle" value="30"/>  
    <property name="maxWait" value="1000"/>  

	<property name="testOnBorrow" value="true"/>  
    <property name="testWhileIdle" value="true"/>  
    <property name="testOnReturn" value="true"/> 
    <property name="minEvictableIdleTimeMillis" value="300000" />  
    <property name="timeBetweenEvictionRunsMillis" value="120000" /> 
    <property name="validationQuery" value="select 1 from dual" />   
  </bean>
 	

   <!-- 多个数据源的SqlSessionFactory名称不能相等 -->  
  <bean id="studentSqlSessionFactory" name="studentSqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="studentDataSource" />
    <!-- 加载mybatis配置类 -->
    <property name="configLocation" value="resource/mybatis_student.xml" />
  </bean>
  <!-- ScanMapperFiles: mapper类要扫描的包；扫描mapper类 ，也不能同名 -->
  <bean name="studentMapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
     <!-- mapper类所在的包  -->
    <property name="basePackage" value="com.my.student.mapper"/> 
    <property name="sqlSessionFactoryBeanName" value="studentSqlSessionFactory"/> 
  </bean>



  <!-- ================================事务相关控制=================================================    -->
  <!-- 开启通过注解实现事务，设置事务的名称 . 事务管理对象的名称也要不一样。系统默认事务管理对象名称为transactionManager -->
  <tx:annotation-driven transaction-manager="studentTransactionManager"/>
  <bean name="studentTransactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">     
          <property name="dataSource" ref="studentDataSource"></property>
    </bean>     
 
</beans>

spring_teacher.xml：spring1的spring配置文件

<?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:aop="http://www.springframework.org/schema/aop"
     xmlns:tx="http://www.springframework.org/schema/tx"
     xmlns:context="http://www.springframework.org/schema/context"
     xsi:schemaLocation="
     http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
     http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
     http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
     http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">

 
  <!-- 多个数据源的 DataSource名称不能相等 -->
  <bean id="teacherDataSource" destroy-method="close"
    class="org.apache.commons.dbcp.BasicDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://${main.db.sIp}:${main.db.sPort}/spring1" />  
    <property name="username" value="${main.db.sUsername}" />
    <property name="password" value="${main.db.sPassword}" />
    <property name="initialSize" value="20"/>  
    <property name="maxActive" value="200"/>  
    <property name="maxIdle" value="30"/>  
    <property name="maxWait" value="1000"/>  

	<property name="testOnBorrow" value="true"/>  
    <property name="testWhileIdle" value="true"/>  
    <property name="testOnReturn" value="true"/> 
    <property name="minEvictableIdleTimeMillis" value="300000" />  
    <property name="timeBetweenEvictionRunsMillis" value="120000" /> 
    <property name="validationQuery" value="select 1 from dual" />   
  </bean>
 	

  <!-- 多个数据源的SqlSessionFactory名称不能相等 -->  
  <bean id="teacherSessionFactory"  name="teacherSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="teacherDataSource" />
    <!-- 加载mybatis的配置文件 -->
    <property name="configLocation" value="resource/mybatis_teacher.xml" />
  </bean>
  <!-- ScanMapperFiles 扫描mapper类 ，也不能同名-->
  <bean  name="teacherMapperScannerConfigurer"   class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <!-- mapper类所在的包  -->
    <property name="basePackage" value="com.my.teacher.mapper"/>  
    <property name="sqlSessionFactoryBeanName" value="teacherSessionFactory"/> 
  </bean>

  <!-- ================================事务相关控制=================================================    -->
  <!-- 开启通过注解实现事务，设置事务的名称 . 事务管理对象的名称也要不一样。系统默认事务管理对象名称为transactionManager -->
  <tx:annotation-driven  transaction-manager="teachaerTransactionManager" />
  
  <bean name="teachaerTransactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">     
      <property name="dataSource" ref="teacherDataSource"></property>
  </bean>     
</beans>

重点说明：

mybatis + spring 中，多数据库源的配置和单数据源配置和相似，最大的不同时，2个数据源的配置的名称不能相等。如上面配置spring配置xml中 DataSource、SqlSessionFactoryBean、MapperScannerConfigurer、DataSourceTransactionManager等在2个spring配置名称中都不相等。尤其是事务管理类DataSourceTransactionManager，必须通过以下方式开启并进行命名：<tx:annotation-driven transaction-manager="teachaerTransactionManager" />

同时部分只演示了同时操作2个数据库，事务操作通过更新操作才能够更好演示出来，其实以上已经实现事务了，这里就省略步骤了。

以上内容源代码见附近

参考文献：

Spring下mybatis多数据源配置

Spring_Mybatis.zip (25.3 KB)
描述: 源代码
下载次数: 290

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2012-11-04 22:47
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分类:开源软件
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2 楼 xj56ai 2016-07-18

能不能提供一下包

1 楼 zhangliguoaccp 2015-10-29

您好，我也用到同样的功能了，但是我的
15:14:20,838 WARN [ConfigurationClassEnhancer]
@Bean method SpringIocMappingConfig.mappperConfigurer is non-static and returns an object assignable to Spring's BeanFactoryPostProcessor interface. This will result in a failure to process annotations such as @Autowired, @Resource and @PostConstruct within the method's declaring @Configuration class. Add the 'static' modifier to this method to avoid these container lifecycle issues; see @Bean Javadoc for complete details

15:14:20,856 WARN [ConfigurationClassEnhancer]
@Bean method SpringIocMappingConfig2.mappperConfigurerAgreement is non-static and returns an object assignable to Spring's BeanFactoryPostProcessor interface. This will result in a failure to process annotations such as @Autowired, @Resource and @PostConstruct within the method's declaring @Configuration class. Add the 'static' modifier to this method to avoid these container lifecycle issues; see @Bean Javadoc for complete details

启动服务器，就停在这了，我QQ602525391 希望能与你取得联系

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