SpringBoot+mybatis+mysql多數據源配置

需求

    springboot+mybatis+mysql整合工程，結合tk-mybatis技術，實現多個數據源配置。

實現方式一

• 第一步：application.yml配置文件

spring:
  # 多數據源
  permission:
    datasource:
      url: jdbc:mysql://127.0.0.1:3306/permission?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
      username: root
      password: root
      type: com.alibaba.druid.pool.DruidDataSource
  account:
    datasource:
      url: jdbc:mysql://127.0.0.1:3306/account?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
      username: root
      password: root
      type: com.alibaba.druid.pool.DruidDataSource

• 第二步：取消springboot自動初始化數據源

@SpringBootApplication(exclude = {
        DataSourceAutoConfiguration.class,
        DataSourceTransactionManagerAutoConfiguration.class,
        JdbcTemplateAutoConfiguration.class})
public class ProviderApplication {

    public static void main(String[] args) {
        SpringApplication.run(ProviderApplication.class, args);
    }
}

• 第三步：數據源配置實體類

    第一數據源：

package com.dashboard.common.config;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import tk.mybatis.spring.annotation.MapperScan;

import javax.annotation.Resource;
import javax.sql.DataSource;

/**
 * @author konglinghui
 * @description account數據源配置
 * @date 2020/4/19 10:09
 **/
@Configuration
@MapperScan(basePackages = {"com.dashboard.mapper.account"}, sqlSessionTemplateRef = "accountSqlSessionTemplate")
public class AccountDataSourceConfig {

    private static final Logger LOGGER = LoggerFactory.getLogger(AccountDataSourceConfig.class);

    /**
     * 數據源配置對象
     * Primary 表示默認的對象，Autowire可注入，不是默認的得明確名稱注入
     *
     * @return
     */
    @Bean
    // @Primary
    @ConfigurationProperties("spring.account.datasource")
    public DataSourceProperties accountDataSourceProperties() {
        return new DataSourceProperties();
    }

    /**
     * 數據源對象
     *
     * @return
     */
    @Bean
    public DataSource accountDataSource() {
        DataSourceProperties dataSourceProperties = this.accountDataSourceProperties();
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }

    /**
     * 配置事務
     *
     * @param accountDataSource
     * @return
     */
    @Bean
    @Resource
    public PlatformTransactionManager accountTransactionManager(DataSource accountDataSource) {
        return new DataSourceTransactionManager(accountDataSource);
    }

    /**
     * 配置Mapper路徑
     *
     * @param dataSource
     * @return
     */
    @Bean
    public SqlSessionFactory accountSqlSessionFactory(@Qualifier("accountDataSource") DataSource dataSource) {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        // 添加XML目錄
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try {
            sqlSessionFactoryBean.setTypeAliasesPackage("com.dashboard.entity");
            sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath*:mapper/**Mapper.xml"));
            return sqlSessionFactoryBean.getObject();
        } catch (Exception e) {
            if (LOGGER.isInfoEnabled()) {
                LOGGER.info("配置Mapper路徑發生異常:{}", e.getMessage());
            }
            e.printStackTrace();
        }

        return null;
    }

    /**
     * 配置SqlSessionTemplate
     *
     * @param sqlSessionFactory
     * @return
     */
    @Bean
    public SqlSessionTemplate accountSqlSessionTemplate(@Qualifier("accountSqlSessionFactory")
                                                                SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

    第二數據源：

package com.dashboard.common.config;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import tk.mybatis.spring.annotation.MapperScan;

import javax.annotation.Resource;
import javax.sql.DataSource;

/**
 * @author konglinghui
 * @description permission數據源配置
 * @date 2020/4/19 10:09
 **/
@Configuration
@MapperScan(
        basePackages = {"com.dashboard.mapper.permission", "com.dashboard.mapper.system"},
        sqlSessionTemplateRef = "permissionSqlSessionTemplate")
public class PermissionDataSourceConfig {

    private static final Logger LOGGER = LoggerFactory.getLogger(PermissionDataSourceConfig.class);

    /**
     * 數據源配置對象
     * Primary 表示默認的對象，Autowire可注入，不是默認的得明確名稱注入
     *
     * @return
     */
    @Bean
    // @Primary
    @ConfigurationProperties("spring.permission.datasource")
    public DataSourceProperties permissionDataSourceProperties() {
        return new DataSourceProperties();
    }

    /**
     * 數據源對象
     *
     * @return
     */
    @Bean
    public DataSource permissionDataSource() {
        DataSourceProperties dataSourceProperties = this.permissionDataSourceProperties();
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }

    /**
     * 配置事務
     *
     * @param permissionDataSource
     * @return
     */
    @Bean
    @Resource
    public PlatformTransactionManager permissionTransactionManager(DataSource permissionDataSource) {
        return new DataSourceTransactionManager(permissionDataSource);
    }

    /**
     * 配置Mapper路徑
     *
     * @param dataSource
     * @return
     */
    @Bean
    public SqlSessionFactory permissionSqlSessionFactory(@Qualifier("permissionDataSource") DataSource dataSource) {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        // 添加XML目錄
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try {
            sqlSessionFactoryBean.setTypeAliasesPackage("com.dashboard.entity");
            sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath*:mapper/**Mapper.xml"));
            return sqlSessionFactoryBean.getObject();
        } catch (Exception e) {
            if (LOGGER.isInfoEnabled()) {
                LOGGER.info("配置Mapper路徑發生異常:{}", e.getMessage());
            }
            e.printStackTrace();
        }

        return null;
    }

    /**
     * 配置SqlSessionTemplate
     *
     * @param sqlSessionFactory
     * @return
     */
    @Bean
    public SqlSessionTemplate permissionSqlSessionTemplate(@Qualifier("permissionSqlSessionFactory")
                                                                   SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

@Primary：該註解表示在同一個接口有多個實現類可以注入的時候，默認選擇哪一個，而不是讓autowire註解報錯，官網要求當多個數據源時，必須指定一個datasource，另一個datasource則不用添加。（這裏不需要，因爲這裏沒有主從數據庫，所有的數據源都是一樣的）。
@Qualifier ：根據名稱進行注入，通常是在具有相同的多個類型的實例的一個注入（例如有多個DataSource類型的實例）。
@MapperScan(basePackages = {"com.example.fjk.demo.dao.foo"}, sqlSessionTemplateRef = "fooSqlSessionTemplate") ：basePackages爲Dao所在的包，sqlSessionTemplateRef要引用的實例。

常見問題

• Failed to determine a suitable driver class問題

異常信息如下：

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-05-06 21:27:18.275 ERROR 10968 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   :

***************************
APPLICATION FAILED TO START
***************************

Description:

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class


Action:

Consider the following:
    If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
    If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).


Process finished with exit code 1

問題根源：
1. ConfigurationProperties註解屬性值配置錯誤；
2. 取消springboot自動初始化數據源操作失敗。

參考鏈接

• Springboot+Mybatis配置多數據源
• SpringBoot啓動報錯Failed to determine a suitable driver class