四时宝库

作者 | 山高人为峰ws

来源 | urlify.cn/M7RZzq

场景分析：在同一个项目中可能会遇到需要连接操作多个数据库，如果是这种情况下的话，我们在application.yml中数据源的配置就无法满足这种需求，那怎么解决呢？我们只能通过java config的方式去配置多数据源，从而满足需求。

1.首先看下application.yml关于数据源的配置（其实这里的配置和传统的一样）

mybatis:
  mapperLocations: classpath:/mapper/*.xml
  configuration:
    call-setters-on-nulls: true

spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    druid:
      url: jdbc:mysql://localhost:3306/zjuap            #mysql配置
      driver-class-name: com.mysql.jdbc.Driver          #mysql配置
      #url: jdbc:oracle:thin:@127.0.0.1:1521:orcl         #oracle配置
      #driver-class-name: oracle.jdbc.OracleDriver        #oracle配置
      username: zjft
      #密码加密 java -cp druid-1.1.10.jar com.alibaba.druid.filter.config.ConfigTools you_password
      #密码为加密的 zjft8888
      password: MA+imF+ye4ptAG+nuJsA/RYs8MZPTXotRC0DBdR5rFeAXHL8h7kxFJEcmukugC1N7g==
      initial-size: 10
      max-active: 20
      min-idle: 4
      max-wait: 60000
      validation-query: SELECT 1        #mysql配置
      #validation-query: select 1 from dual       #oracle配置
      validation-query-timeout: 30000
      #配置连接属性，是否开启密码加密，以及配置加密加密的公钥 public key
      connection-properties: config.decrypt=true;config.decrypt.key=MFwwDQYJQ/BRnCnkCAwEAAQ==
      filter:
        config:
          enabled: true   #如果启用密码加密配置的话，这里必须开启，目的是注入密码加解密过滤器

2.相关依赖添加

<!--ORM框架-->
        <dependency>
              <groupId>org.mybatis.spring.boot</groupId>
              <artifactId>mybatis-spring-boot-starter</artifactId>
              <version>2.0.1</version>
        </dependency>
        <dependency>
             <groupId>com.github.pagehelper</groupId>
             <artifactId>pagehelper-spring-boot-starter</artifactId>
             <version>1.2.9</version>
        </dependency>        
       <!--Druid连接池-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>        
       <!--数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.oracle</groupId>
            <artifactId>ojdbc6</artifactId>
            <version>11.2.0.3</version>
            <scope>runtime</scope>
        </dependency>

3.接下来就是java config的配置

@Configuration
@ConditionalOnMissingBean({Marker.class}) //这里是我的自动装配条件注解
@MapperScan(basePackages = "com.zjft.uap.mapper.dao", sqlSessionTemplateRef = "zjuapSqlSessionTemplate")
public class DefaultDBSourceConfiguration {
 
    /**
     * 创建主数据源对象，注入到Spring
     * 可扩展多个数据源
     */
    @Bean(name = "zjuapDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.druid") //注意这里，读取application.yml配置
    public DataSource dataSource(ConfigFilter configFilter) {
        // 这里是个坑，如果自定义数据源需要对密码加密的话，必须要加上这个过滤器，否则连接会报错
        DruidDataSource dataSource = new DruidDataSource();
        /* 下面的这个ConfigFilter必须得加，否则在application.yml中配置密码加密，在启动项目时会报错
        * [com.alibaba.druid.pool.DruidDataSource] [ERROR] create connection SQLException, url: jdbc:mysql://localhost:3306/zjuap, errorCode 1045, state 28000    *java.sql.SQLException: Access denied for user 'zjft'@'localhost' (using password: YES)
        */
        List filters = new ArrayList<ConfigFilter>(){{
            add(configFilter);
        }};
        dataSource.setProxyFilters(filters);
        return dataSource;
    }
 
    /**
     * 从配置文件获取主数据源的连接信息
     */
    @Value("${mybatis.mapperLocations}")
    private String mapperLocation;
 
    @Bean
    public DatabaseIdProvider databaseIdProvider(){
        DatabaseIdProvider databaseIdProvider = new VendorDatabaseIdProvider();
        Properties p = new Properties();
        p.setProperty("Oracle", "oracle");
        p.setProperty("MySQL", "mysql");
        databaseIdProvider.setProperties(p);
        return databaseIdProvider;
    }
 
    /**
     *创建SqlSessionFactory
     */
    @Bean(name = "zjuapSqlSessionFactory")
    @Primary
    public SqlSessionFactory sqlSessionFactory(@Qualifier("zjuapDataSource") DataSource dataSource, MybatisProperties mybatisProperties) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(mapperLocation));
        bean.setConfiguration(mybatisProperties.getConfiguration());
        bean.setDatabaseIdProvider(databaseIdProvider());
        bean.setVfs(SpringBootVFS.class);
        return bean.getObject();
    }
 
    /**
     * 配置事务
     */
    @Bean(name = "zjuapTransactionManager")
    @Primary
    public DataSourceTransactionManager transactionManager(@Qualifier("zjuapDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
 
    /**
     *创建SqlSessionTemplate
     */
    @Bean(name = "zjuapSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("zjuapSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}