123456 | @org.springframework.context.annotation.Configuration@ConditionalOnClass({ SqlSessionFactory.class, SqlSessionFactoryBean.class })@ConditionalOnSingleCandidate(DataSource.class)@EnableConfigurationProperties(MybatisProperties.class)@AutoConfigureAfter(DataSourceAutoConfiguration.class)public class MybatisAutoConfiguration implements InitializingBean { |
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@ConditionalOnSingleCandidate(DataSource.class)
,什么鬼?该注解的意思就是IOC容器中只有一个指定的候选对象才起作用,但是我们注入了几个DataSource,足足三个啊,这还起作用吗?那不废话嘛。DataSourceTransactionManagerAutoConfiguration
,如下:12345 | public class DataSourceTransactionManagerAutoConfiguration { @Configuration @ConditionalOnSingleCandidate(DataSource.class) static class DataSourceTransactionManagerConfiguration { |
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@ConditionalOnSingleCandidate(DataSource.class)
同样的醒目,mmp,这不玩我呢吗。这怎么搞?@ConditionalOnSingleCandidate
注解搞了什么,进去看看,有如下的介绍:1 | The condition will also match if multiple matching bean instances are already contained in the BeanFactory but a primary candidate has been defined; essentially, the condition match if auto-wiring a bean with the defined type will succeed. |
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12345678910111213141516171819202122232425262728293031323334353637383940414243444546 | /** * @Description 数据源的配置 * @Author CJB * @Date 2020/3/9 13:45 */@Configuration@MapperScan(basePackages = {"com.vivachek.service.dao","com.vivachek.service.dao2"})public class DatasourceConfig { /** * 注入数据源1 */ @ConfigurationProperties(prefix = "spring.datasource1") @Bean(value = "dataSource1") public DataSource dataSource1() { return new DruidDataSource(); } /** * 第二个数据源 */ @Bean(name = "dataSource2") @ConfigurationProperties(prefix = "spring.datasource2") public DataSource dataSource2() { return new DruidDataSource(); } /** * 动态数据源 * * @return */ @Bean @Primary public DynamicDataSource dynamicDataSource() { DynamicDataSource dataSource = new DynamicDataSource(); //默认数据源,在没有切换数据源的时候使用该数据源 dataSource.setDefaultTargetDataSource(dataSource2()); HashMap<Object, Object> map = Maps.newHashMap(); map.put("dataSource1", dataSource1()); map.put("dataSource2", dataSource2()); //设置数据源Map,动态切换就是根据key从map中获取 dataSource.setTargetDataSources(map); return dataSource; }} |
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DynamicDataSource
添加了一个@Primary就省去了SqlSessionFactory和TransactionManager的手动配置,是不是很easy并且显得自己很牛叉,太有成就感了…..DataSourceInitializerInvoker
造成的循环依赖了,果不其然,其中确实依赖了DataSource,源码如下:123456 | DataSourceInitializerInvoker(ObjectProvider<DataSource> dataSource, DataSourceProperties properties, ApplicationContext applicationContext) { this.dataSource = dataSource; this.properties = properties; this.applicationContext = applicationContext; } |
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DataSourceInitializerInvoker
是什么时候注入到IOC容器中的,因此我们找到了DataSourceAutoConfiguration
,继而找到了DataSourceInitializationConfiguration
这个配置类,源码如下:12345678910111213141516171819202122232425262728 | @Configuration@ConditionalOnClass({ DataSource.class, EmbeddedDatabaseType.class })@EnableConfigurationProperties(DataSourceProperties.class)@Import({ DataSourcePoolMetadataProvidersConfiguration.class, DataSourceInitializationConfiguration.class })public class DataSourceAutoConfiguration { @Configuration @Conditional(EmbeddedDatabaseCondition.class) @ConditionalOnMissingBean({ DataSource.class, XADataSource.class }) @Import(EmbeddedDataSourceConfiguration.class) protected static class EmbeddedDatabaseConfiguration { } @Configuration @Conditional(PooledDataSourceCondition.class) @ConditionalOnMissingBean({ DataSource.class, XADataSource.class }) @Import({ DataSourceConfiguration.Hikari.class, DataSourceConfiguration.Tomcat.class, DataSourceConfiguration.Dbcp2.class, DataSourceConfiguration.Generic.class, DataSourceJmxConfiguration.class }) protected static class PooledDataSourceConfiguration { } } @Configuration@Import({ DataSourceInitializerInvoker.class, DataSourceInitializationConfiguration.Registrar.class })class DataSourceInitializationConfiguration { |
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@ConditionalOnMissingBean({ DataSource.class, XADataSource.class })
,这什么鬼,不多说了,相信读过SpringBoot源码的都知道,这个配置类根本不起作用啊,那还要它干嘛,直接搞掉不就完事了。好了,分析到这里终于知道解决的方案了,搞掉DataSourceAutoConfiguration
,怎么搞呢?一个注解搞定。12 | //排除配置类@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class}) |
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