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

    org.mybatis.spring.boot
    mybatis-spring-boot-starter
    2.2.2



    com.github.pagehelper
    pagehelper-spring-boot-starter
    1.3.0



    mysql
    mysql-connector-java
    8.0.26
    runtime



    com.oracle
    ojdbc6
    11.2.0.3



    cn.hutool
    hutool-all
    5.7.22



    org.springframework.boot
    spring-boot-configuration-processor
    true

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.Driver
      jdbc-url: jdbc:mysql://localhost:3306/studb?characterEncoding=UTF-8&useUnicode=true
      username: root
      password: root
    db2:
      driver-class-name: oracle.jdbc.driver.OracleDriver
      jdbc-url: jdbc:oracle:thin:@//localhost:1521/XE
      username: root
      password: root
#  分页配置
  pagehelper:
    db1:
      dialect: mysql
      offsetAsPageNum: true
      rowBoundsWithCount: true
      reasonable: true
      supportMethodsArguments: true
      params: count=countSql;pageNum=pageNum;pageSize=pageSize;
    db2:
      dialect: oracle
      offsetAsPageNum: true
      rowBoundsWithCount: true
      reasonable: true
      supportMethodsArguments: true
      params: 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 {
    @Resource
    private PrimaryMybatisProperties primaryMybatisProperties;

    @Bean(name = "dataSource1")
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource.db1")
    public DataSource dataSource1(){
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "sqlSessionFactory1")
    @Primary
    public 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));
        // mybatis
        org.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")
    @Primary
    public SqlSessionTemplate sqlSessionTemplate1(@Qualifier("sqlSessionFactory1") SqlSessionFactory sqlSessionFactory1) {
        return new SqlSessionTemplate(sqlSessionFactory1);
    }

    @Bean(name = "dataSourceTransactionManager1")
    @Primary
    public 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 {
    @Resource
    private SecondMybatisProperties secondMybatisProperties;

    @Bean(name = "dataSource2")
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource.db2")
    public DataSource dataSource2(){
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "sqlSessionFactory2")
    @Primary
    public 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")
    @Primary
    public SqlSessionTemplate sqlSessionTemplate1(@Qualifier("sqlSessionFactory2") SqlSessionFactory sqlSessionFactory2) {
        return new SqlSessionTemplate(sqlSessionFactory2);
    }

    @Bean(name = "dataSourceTransactionManager2")
    @Primary
    public 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 {
    @Resource
    private StudentServiceI studentService;

    @GetMapping
    public PageInfo queryByPage(int pageNum, int pageSize, Student student){
        return studentService.queryByPage(pageNum,pageSize,student);
    }
}

@RestController
@RequestMapping("/user")
public class UserController {
    @Resource
    private UserServiceI userService;

    @GetMapping
    public PageInfo 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 queryByPage(int pageNum, int pageSize, Student student);

}

@Service
public class StudentServiceImpl implements StudentServiceI {
    @Resource
    private StudentMapper studentMapper;
    @Override
    public PageInfo 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 students = studentMapper.selectByPage(student);
        PageInfo pageInfo = new PageInfo<>(students);
        return pageInfo;
    }
}

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

@Service
public class UserServiceImpl implements UserServiceI {
    @Resource
    private UserMapper userMapper;
    @Override
    public PageInfo 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 users = userMapper.selectByPage(user);
        PageInfo 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 selectByPage(@Param("student") Student student);
}

src/main/resources/mapper1/StudentMapper.xml

    
        id,name,age,gender,address,birth
    
    
        select
        
        from student
        
            
                and id = #{student.id}
            
            
                
                and name like #{stuName}
            
        
    

（2）db2数据源对应的mapper层

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

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

src/main/resources/mapper2/UserMapper.xml

    
        id,user_name
    
    
        select
        
        from sys_user
        
            
                and id = #{student.id}
            
            
                
                and user_name like #{userName}
            
        
    

3.3 测试

        使用Postman进行测试，如下：

（1）使用db1数据源

（2）使用db2数据源