SpringBoot+Mybatis实现多数据源+分页

1 主要依赖版本

（1）SpringBoot 2.7.8

（2）Mybatis 2.2.2

（3）Pagehelper 1.3.0

（4）MySQL 8.0.26

（5）Oracle 11.2.0.3

2 概述

（1）这里使用两个数据源，分别是MySQL和Oracle，配置两个数据库；

（2）针对以上数据源分别配置Mybatis和Pagehelper(实现分页)；

（3）数据源、Mybatis、分页都自定义配置，在启动类关闭它们的自动配置。

3 SpringBoot整合Mybatis实现多数据源动态切换

3.1 整合与配置

3.1.1 相关依赖pom.xml

<!-- mybatis-spring-boot-starter -->
<dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.2.2</version>
</dependency>
<!-- pagehelper-spring-boot-starter -->
<dependency><groupId>com.github.pagehelper</groupId><artifactId>pagehelper-spring-boot-starter</artifactId><version>1.3.0</version>
</dependency>
<!-- mysql -->
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.26</version><scope>runtime</scope>
</dependency>
<!-- oracle -->
<dependency><groupId>com.oracle</groupId><artifactId>ojdbc6</artifactId><version>11.2.0.3</version>
</dependency>
<!-- hutool -->
<dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.7.22</version>
</dependency>
<!-- yml文件自定义配置，输入提示-->
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-configuration-processor</artifactId><optional>true</optional>
</dependency>

3.1.2 application.yml配置

yml配置中配置了db1和db2两个数据源以及分页，db1对应MySQL，db2对应Oracle，如果不需要分页这里可以省去spring.pagehelper下的配置。

spring:datasource:db1:driver-class-name: com.mysql.cj.jdbc.Driverjdbc-url: jdbc:mysql://localhost:3306/studb?characterEncoding=UTF-8&useUnicode=trueusername: rootpassword: rootdb2:driver-class-name: oracle.jdbc.driver.OracleDriverjdbc-url: jdbc:oracle:thin:@//localhost:1521/XEusername: rootpassword: root
#  分页配置pagehelper:db1:dialect: mysqloffsetAsPageNum: truerowBoundsWithCount: truereasonable: truesupportMethodsArguments: trueparams: count=countSql;pageNum=pageNum;pageSize=pageSize;db2:dialect: oracleoffsetAsPageNum: truerowBoundsWithCount: truereasonable: truesupportMethodsArguments: trueparams: count=countSql;pageNum=pageNum;pageSize=pageSize;

3.1.3 yml中分页配置设置到对应Bean

这里使用@ConfigurationProperties注解将yml配置文件中指定前缀的数据自动填充到Bean。

（1）db1数据源的分页属性Bean

@Data
@Component
@ConfigurationProperties(prefix = "spring.pagehelper.db1")
public class PrimaryMybatisProperties {private String dialect;private String offsetAsPageNum;private String rowBoundsWithCount;private String reasonable;private String supportMethodsArguments;private String params;
}

（2）db2数据源的分页属性Bean

@Data
@Component
@ConfigurationProperties(prefix = "spring.pagehelper.db2")
public class SecondMybatisProperties {private String dialect;private String offsetAsPageNum;private String rowBoundsWithCount;private String reasonable;private String supportMethodsArguments;private String params;
}

3.1.4 数据源配置

（1）db1的数据源配置PrimaryDataSourceConfig.java

注意：多数据源情况下这里使用@Primary注解指定默认使用的是db1。

@Configuration
@MapperScan(basePackages = "com.wen.mapper1", sqlSessionFactoryRef = "sqlSessionFactory1")
public class PrimaryDataSourceConfig {@Resourceprivate PrimaryMybatisProperties primaryMybatisProperties;@Bean(name = "dataSource1")@Primary@ConfigurationProperties(prefix = "spring.datasource.db1")public DataSource dataSource1(){return DataSourceBuilder.create().build();}@Bean(name = "sqlSessionFactory1")@Primarypublic SqlSessionFactory sqlSessionFactory1(@Qualifier("dataSource1") DataSource dataSource1) throws Exception{SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();sessionFactoryBean.setDataSource(dataSource1);String locationPattern = "classpath*:mapper1/**/*.xml";PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();sessionFactoryBean.setMapperLocations(resolver.getResources(locationPattern));// mybatisorg.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();configuration.setMapUnderscoreToCamelCase(true);configuration.setLogImpl(StdOutImpl.class);sessionFactoryBean.setConfiguration(configuration);// 分页Interceptor interceptor = new PageInterceptor();Properties properties = new Properties();properties.setProperty("helperDialect", primaryMybatisProperties.getDialect());properties.setProperty("offsetAsPageNum", primaryMybatisProperties.getOffsetAsPageNum());properties.setProperty("rowBoundsWithCount", primaryMybatisProperties.getRowBoundsWithCount());properties.setProperty("reasonable", primaryMybatisProperties.getReasonable());properties.setProperty("supportMethodsArguments",primaryMybatisProperties.getSupportMethodsArguments());properties.setProperty("params",primaryMybatisProperties.getParams());interceptor.setProperties(properties);sessionFactoryBean.setPlugins(interceptor);return sessionFactoryBean.getObject();}@Bean(name = "sqlSessionTemplate1")@Primarypublic SqlSessionTemplate sqlSessionTemplate1(@Qualifier("sqlSessionFactory1") SqlSessionFactory sqlSessionFactory1) {return new SqlSessionTemplate(sqlSessionFactory1);}@Bean(name = "dataSourceTransactionManager1")@Primarypublic DataSourceTransactionManager dataSourceTransactionManager1(@Qualifier("dataSource1") DataSource dataSource1){return new DataSourceTransactionManager(dataSource1);}
}

（2）db2的数据源配置SecondDataSourceConfig.java

@Configuration
@MapperScan(basePackages = "com.wen.mapper2",sqlSessionFactoryRef = "sqlSessionFactory2")
public class SecondDataSourceConfig {@Resourceprivate SecondMybatisProperties secondMybatisProperties;@Bean(name = "dataSource2")@Primary@ConfigurationProperties(prefix = "spring.datasource.db2")public DataSource dataSource2(){return DataSourceBuilder.create().build();}@Bean(name = "sqlSessionFactory2")@Primarypublic SqlSessionFactory sqlSessionFactory1(@Qualifier("dataSource2") DataSource dataSource2) throws Exception{SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();sessionFactoryBean.setDataSource(dataSource2);String locationPattern = "classpath*:mapper2/**/*.xml";PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();sessionFactoryBean.setMapperLocations(resolver.getResources(locationPattern));// mybatis下划线转驼峰org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();configuration.setMapUnderscoreToCamelCase(true);configuration.setLogImpl(StdOutImpl.class);sessionFactoryBean.setConfiguration(configuration);// 分页配置Interceptor interceptor = new PageInterceptor();Properties properties = new Properties();properties.setProperty("helperDialect", secondMybatisProperties.getDialect());properties.setProperty("offsetAsPageNum", secondMybatisProperties.getOffsetAsPageNum());properties.setProperty("rowBoundsWithCount", secondMybatisProperties.getRowBoundsWithCount());properties.setProperty("reasonable", secondMybatisProperties.getReasonable());properties.setProperty("supportMethodsArguments",secondMybatisProperties.getSupportMethodsArguments());properties.setProperty("params",secondMybatisProperties.getParams());interceptor.setProperties(properties);sessionFactoryBean.setPlugins(interceptor);return sessionFactoryBean.getObject();}@Bean(name = "sqlSessionTemplate2")@Primarypublic SqlSessionTemplate sqlSessionTemplate1(@Qualifier("sqlSessionFactory2") SqlSessionFactory sqlSessionFactory2) {return new SqlSessionTemplate(sqlSessionFactory2);}@Bean(name = "dataSourceTransactionManager2")@Primarypublic DataSourceTransactionManager dataSourceTransactionManager1(@Qualifier("dataSource2") DataSource dataSource2){return new DataSourceTransactionManager(dataSource2);}
}

注意：如果项目中有使用@Transactional事务注解，必须分别配置数据源的事务管理，以上代码中已经配置。

3.1.5 启动类排除相关自动配置

启动类排除数据源(DataSourceAutoConfiguration.class)、Mybatis(MybatisAutoConfiguration.class)、分页(PageHelperAutoConfiguration.class)的自动配置。

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class, MybatisAutoConfiguration.class, PageHelperAutoConfiguration.class})
public class Application {public static void main(String[] args) {SpringApplication.run(Application.class, args);}}

3.2 示例代码

3.2.1 po

src/main/java/com/wen/po

@Data
public class Student {private Integer id;private String name;private Integer age;private String gender;private String address;private Date birth;
}

@Data
public class User {private String id;private String userName;
}

3.2.2 controller层

src/main/java/com/wen/controller

@RestController
@RequestMapping("/student")
public class StudentController {@Resourceprivate StudentServiceI studentService;@GetMappingpublic PageInfo<Student> queryByPage(int pageNum, int pageSize, Student student){return studentService.queryByPage(pageNum,pageSize,student);}
}

@RestController
@RequestMapping("/user")
public class UserController {@Resourceprivate UserServiceI userService;@GetMappingpublic PageInfo<User> queryByPage(int pageNum, int pageSize, User user){return userService.queryByPage(pageNum,pageSize,user);}
}

3.2.3 service层

src/main/java/com/wen/service

public interface StudentServiceI {PageInfo<Student> queryByPage(int pageNum, int pageSize, Student student);}

@Service
public class StudentServiceImpl implements StudentServiceI {@Resourceprivate StudentMapper studentMapper;@Overridepublic PageInfo<Student> queryByPage(int pageNum, int pageSize, Student student) {if (pageNum <= 0) {pageNum = 1;}if (pageSize <= 0) {pageSize = 10;}if(ObjectUtil.isEmpty(student)){student = new Student();}PageMethod.startPage(pageNum,pageSize);List<Student> students = studentMapper.selectByPage(student);PageInfo<Student> pageInfo = new PageInfo<>(students);return pageInfo;}
}

public interface UserServiceI {PageInfo<User> queryByPage(int pageNum, int pageSize, User user);
}

@Service
public class UserServiceImpl implements UserServiceI {@Resourceprivate UserMapper userMapper;@Overridepublic PageInfo<User> queryByPage(int pageNum, int pageSize, User user) {if (pageNum <= 0) {pageNum = 1;}if (pageSize <= 0) {pageSize = 10;}if(ObjectUtil.isEmpty(user)){user = new User();}PageMethod.startPage(pageNum,pageSize);List<User> users = userMapper.selectByPage(user);PageInfo<User> pageInfo = new PageInfo<>(users);return pageInfo;}
}

3.2.4 mapper层

注意不同数据源对应的mapper，数据源配置类中@MapperScan对应的属性basePackages = "com.wen.mapper2"指定数据源对应的mapper。

（1）db1数据源对应的mapper层

src/main/java/com/wen/mapper1/StudentMapper.java

@Mapper
public interface StudentMapper {List<Student> selectByPage(@Param("student") Student student);
}

src/main/resources/mapper1/StudentMapper.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.wen.mapper1.StudentMapper"><sql id="student">id,name,age,gender,address,birth</sql><select id="selectByPage" resultType="com.wen.po.Student">select<include refid="student"/>from student<where><if test="student.id!=null">and id = #{student.id}</if><if test="student.name!=null and student.name!=''"><bind name="stuName" value="'%' + student.name + '%'"/>and name like #{stuName}</if></where></select>
</mapper>

（2）db2数据源对应的mapper层

src/main/java/com/wen/mapper2/UserMapper.java

@Mapper
public interface UserMapper {List<User> selectByPage(@Param("user") User user);
}

src/main/resources/mapper2/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.wen.mapper2.UserMapper"><sql id="user">id,user_name</sql><select id="selectByPage" resultType="com.wen.po.User">select<include refid="user"/>from sys_user<where><if test="user.id!=null">and id = #{student.id}</if><if test="user.userName!=null and user.userName!=''"><bind name="userName" value="'%' + user.userName + '%'"/>and user_name like #{userName}</if></where></select>
</mapper>