1.springboot在集成多数据源

1.1引入依赖

<dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>

1.2配置yml文件

其中请务必关注注释下面的不同的数据源的名字，因为下一步是手动获取yml文件的配置，并非自动配置。因为不一定会同时使用这两个数据库，所以我加了enabled开关，如果为true，才会加载数据库配置

spring:
  #mysql数据源
  mysqldb:
    enabled: false
    driver-class-name: com.mysql.cj.jdbc.Driver
    password: root
    url: jdbc:mysql://127.0.0.1:3306/test?characterEncoding=UTF-8&useUnicode=true&serverTimezone=Asia/Shanghai&allowMultiQueries=true&useAffectedRows=true&useSSL=false
    username: root
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
    filters: stat,wall,log4j
    initialSize: 5
    maxActive: 20
    maxPoolPreparedStatementPerConnectionSize: 20
    maxWait: 60000
    minEvictableIdleTimeMillis: 300000
    minIdle: 5
    poolPreparedStatements: true
    testOnBorrow: false
    testOnReturn: false
    testWhileIdle: true
    timeBetweenEvictionRunsMillis: 60000
    validationQuery: SELECT 1 FROM DUAL
  #psql数据源
  psqldb:
    enabled: true
    driver-class-name: org.postgresql.Driver
    url: jdbc:postgresql://127.0.0.1:9543/test
    username: postgres
    password: postgres
    # 初始化大小，最小，最大
    initialSize: 1
    minIdle: 3
    maxActive: 200
    # 配置获取连接等待超时的时间
    maxWait: 60000
    # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
    timeBetweenEvictionRunsMillis: 60000
    # 配置一个连接在池中最小生存的时间，单位是毫秒
    minEvictableIdleTimeMillis: 40000
    validationQuery: select 'x'
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false

1.3创建config包，这个只要让SpringBoot扫描到就行，并不需要在启动类上特别加注释

mysql的相关配置

import lombok.Data;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import java.io.Serializable;


@Component
@Data
@ConfigurationProperties(prefix = "spring.mysqldb")
public class MysqlDataSourceProperties implements Serializable {
    
    

    private String driverClassName;
    private String url;
    private String username;
    private String password;
    private String connectionProperties;
    private String filters;
    private Integer initialSize;
    private Integer maxActive;
    private Integer maxPoolPreparedStatementPerConnectionSize;
    private Integer maxWait;
    private Integer minEvictableIdleTimeMillis;
    private Integer minIdle;
    private boolean poolPreparedStatements;
    private boolean testOnBorrow;
    private boolean testOnReturn;
    private boolean testWhileIdle;
    private Integer timeBetweenEvictionRunsMillis;
    private String validationQuery;
    private boolean enabled;

}

加载MySQL


import com.alibaba.druid.pool.DruidDataSource;
import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.autoconfigure.ConfigurationCustomizer;
import com.baomidou.mybatisplus.autoconfigure.SpringBootVFS;
import com.baomidou.mybatisplus.core.MybatisConfiguration;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import org.apache.ibatis.mapping.DatabaseIdProvider;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;

import javax.sql.DataSource;
import java.util.List;

@Configuration
## ConditionalOnProperty指定enabled开启时，才会加载该数据库相关信息
@ConditionalOnProperty(prefix = "spring.mysqldb", name = "enabled", havingValue = "true")
@MapperScan(basePackages = "com.koal.ipsec.mapper", sqlSessionFactoryRef = "mysqlSqlSessionFactory")
public class MysqlDataSourceConfig {
    
    

    @Autowired
    private MysqlDataSourceProperties mysqlDataSourceProperties;

    @Bean(name = "mysqlDataSource")
    public DataSource dataSource() {
    
    
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(mysqlDataSourceProperties.getDriverClassName());
        dataSource.setUrl(mysqlDataSourceProperties.getUrl());
        dataSource.setUsername(mysqlDataSourceProperties.getUsername());
        dataSource.setPassword(mysqlDataSourceProperties.getPassword());
        dataSource.setInitialSize(mysqlDataSourceProperties.getInitialSize());
        dataSource.setMinIdle(mysqlDataSourceProperties.getMinIdle());
        dataSource.setMaxActive(mysqlDataSourceProperties.getMaxActive());
        return dataSource;
    }

    @Bean
    public PaginationInterceptor paginationInterceptor() {
    
    
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        paginationInterceptor.setDialectType(DbType.MYSQL.getDb());
        return paginationInterceptor;
    }

    @Bean(name = "mysqlSqlSessionFactory")
    @Primary
    public SqlSessionFactory sqlSessionFactory(@Qualifier("mysqlDataSource") DataSource dataSource) throws Exception {
    
    
      ##注意： Mybatis plus分页插件配置必须使用MybatisSqlSessionFactoryBean ，否则分页失效
      ## MybatisSqlSessionFactoryBean 是为了解决扫包的时候无法扫描mybatis-plus的mapper的问题。
        final MybatisSqlSessionFactoryBean mybatisSqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
       ## 重点
        MybatisConfiguration mybatisConfiguration = new MybatisConfiguration();
        mybatisSqlSessionFactoryBean.setConfiguration(mybatisConfiguration);
        mybatisSqlSessionFactoryBean.setDataSource(dataSource);
        mybatisSqlSessionFactoryBean.setPlugins(new Interceptor[]{
    
    paginationInterceptor()});
        ## 指定enum类的扫描
        mybatisSqlSessionFactoryBean.setTypeEnumsPackage("com.test.constant");
        ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
        Resource[] resources = resourcePatternResolver.getResources("classpath*:mapper/*Mapper.xml");
        mybatisSqlSessionFactoryBean.setMapperLocations(resources);
        return mybatisSqlSessionFactoryBean.getObject();
    }
    @Bean(name = "mysqlSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("mysqlSqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
    
    
        return new SqlSessionTemplate(sqlSessionFactory);
    }
    @Bean(name = "mysqlTransactionManager")
    public DataSourceTransactionManager dataSourceTransactionManager(@Qualifier("mysqlDataSource") DataSource dataSource) {
    
    
        return new DataSourceTransactionManager(dataSource);
    }

}

psql相关配置


import lombok.Data;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import java.io.Serializable;

@Component
@Data
@ConfigurationProperties(prefix = "spring.psqldb")
public class PsqlDataSourceProperties implements Serializable {
    
    

    private String driverClassName;
    private String url;
    private String username;
    private String password;
    private Integer initialSize;
    private Integer maxActive;
    private Integer maxWait;
    private Integer minIdle;
    private Integer timeBetweenEvictionRunsMillis;
    private Integer minEvictableIdleTimeMillis;
    private String validationQuery;
    private boolean testOnBorrow;
    private boolean testOnReturn;
    private boolean testWhileIdle;

}



import com.alibaba.druid.pool.DruidDataSource;
import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.core.MybatisConfiguration;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@ConditionalOnProperty(prefix = "spring.psqldb", name = "enabled", havingValue = "true")
@MapperScan(basePackages = "com.koal.ipsec.mapper", sqlSessionFactoryRef = "psqlSqlSessionFactory")
public class PsqlDataSourceConfig {
    
    

    @Autowired
    private PsqlDataSourceProperties psqlDataSourceProperties;

    @Bean(name = "psqlDataSource")
    public DataSource dataSource() {
    
    
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(psqlDataSourceProperties.getDriverClassName());
        dataSource.setUrl(psqlDataSourceProperties.getUrl());
        dataSource.setUsername(psqlDataSourceProperties.getUsername());
        dataSource.setPassword(psqlDataSourceProperties.getPassword());
        dataSource.setInitialSize(psqlDataSourceProperties.getInitialSize());
        dataSource.setMinIdle(psqlDataSourceProperties.getMinIdle());
        dataSource.setMaxActive(psqlDataSourceProperties.getMaxActive());
        return dataSource;
    }

    @Bean
    public PaginationInterceptor paginationInterceptor() {
    
    
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        paginationInterceptor.setDialectType(DbType.POSTGRE_SQL.getDb());
        return paginationInterceptor;
    }

    @Bean(name = "psqlSqlSessionFactory")
    public SqlSessionFactory sqlSessionFactory(@Qualifier("psqlDataSource") DataSource dataSource) throws Exception {
    
    
        final MybatisSqlSessionFactoryBean mybatisSqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
        MybatisConfiguration mybatisConfiguration = new MybatisConfiguration();
        mybatisSqlSessionFactoryBean.setConfiguration(mybatisConfiguration);
        mybatisSqlSessionFactoryBean.setDataSource(dataSource);
        mybatisSqlSessionFactoryBean.setPlugins(new Interceptor[]{
    
    paginationInterceptor()});
       // mybatisSqlSessionFactoryBean.setPlugins(new Interceptor[]{
    
    psqlMybatisPlusConfig.paginationInterceptor()});
        mybatisSqlSessionFactoryBean.setTypeEnumsPackage("com.koal.ipsec.constant");
        ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
        Resource[] resources = resourcePatternResolver.getResources("classpath*:mapper/*Mapper.xml");
        mybatisSqlSessionFactoryBean.setMapperLocations(resources);
        return mybatisSqlSessionFactoryBean.getObject();
    }
    @Bean(name = "psqlSqlSessionTemplate")
    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("psqlSqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
    
    
        return new SqlSessionTemplate(sqlSessionFactory);
    }
    @Bean(name = "psqlTransactionManager")
    public DataSourceTransactionManager dataSourceTransactionManager(@Qualifier("psqlDataSource") DataSource dataSource) {
    
    
        return new DataSourceTransactionManager(dataSource);
    }



}

1.MapperScan内的basePackages 是扫描MyBatis提供的mapper接口所在位置，sqlSessionTemplateRef 里面随意起名，对下面的注解没有影响，但是注意，要和其余几个配置类所起的名字要不同。

2.MysqlDataSourceConfig 类每个方法前面都有@Primary注解，而PsqlDataSourceConfig 类方法就变成了@Qualifier（这里面的名字也是随意，只要这几个类不同就行），这个是防止SpringBoot自动装配的时候，发现存在多个数据源，不知道该使用哪个而在启动时报错。如有两个以上的数据源，就在其余的配置类的方法上和PsqlDataSourceConfig 一样使用@Qualifier注解。

2.解决多数据源mybatis-plus无法进行分页的BUG

问题：
项目配置单数据源的时候，mybatis-plus分页插件正常使用，配置多数据源的时候，mybatis-plus分页插件失效。

2.1注入mybatis-plus分页插件

   @Bean
    public PaginationInterceptor paginationInterceptor() {
    
    
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        paginationInterceptor.setDialectType(DbType.POSTGRE_SQL.getDb());
        return paginationInterceptor;
    }

2.2多数据源下的配置

 @Bean(name = "mysqlSqlSessionFactory")
    @Primary
    public SqlSessionFactory sqlSessionFactory(@Qualifier("mysqlDataSource") DataSource dataSource) throws Exception {
    
    
      ##注意： Mybatis plus分页插件配置必须使用MybatisSqlSessionFactoryBean ，否则分页失效
      ## MybatisSqlSessionFactoryBean 是为了解决扫包的时候无法扫描mybatis-plus的mapper的问题。
        final MybatisSqlSessionFactoryBean mybatisSqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
       ## 重点
        MybatisConfiguration mybatisConfiguration = new MybatisConfiguration();
        mybatisSqlSessionFactoryBean.setConfiguration(mybatisConfiguration);
        mybatisSqlSessionFactoryBean.setDataSource(dataSource);
        mybatisSqlSessionFactoryBean.setPlugins(new Interceptor[]{
    
    paginationInterceptor()});
        ## 指定enum类的扫描
        mybatisSqlSessionFactoryBean.setTypeEnumsPackage("com.test.constant");
        ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
        Resource[] resources = resourcePatternResolver.getResources("classpath*:mapper/*Mapper.xml");
        mybatisSqlSessionFactoryBean.setMapperLocations(resources);
        return mybatisSqlSessionFactoryBean.getObject();
    }

多数据源的配置需要用代码实现，而不是使用默认的properties配置。这里我用了
MybatisSqlSessionFactoryBean配置SqlSessionFactory，而MybatisSqlSessionFactoryBean刚好有个方法就是
setPlugins：用于配置插件。

使用MybatisSqlSessionFactoryBean bean = new MybatisSqlSessionFactoryBean();是为了解决扫包的时候无法扫描mybatis-plus的mapper的问题。

springboot在集成多数据源+mybatis-plus无法进行分页的BUG

springboot在集成多数据源 mysql/psql+ 解决多数据源mybatis-plus无法进行分页的BUG