Spring Boot 優雅整合多數據源

@Bean(name = "dataSource")
    public DataSource dataSource() {
        DruidDataSource druidDataSource = new DruidDataSource();
        druidDataSource.setUrl(url);
        druidDataSource.setUsername(username);
        druidDataSource.setDriverClassName(driverClassName);
        druidDataSource.setPassword(password);
        return druidDataSource;
    }

<!--druid連接池-->
<dependency>
   <groupId>com.alibaba</groupId>
   <artifactId>druid-spring-boot-starter</artifactId>
   <version>1.1.9</version>
</dependency>

@EnableConfigurationProperties({DruidStatProperties.class, DataSourceProperties.class})

spring.datasource.url=jdbc:mysql://120.26.101.xxx:3306/xxx?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowMultiQueries=true&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=xxxx
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
#初始化連接大小
spring.datasource.druid.initial-size=0
#連接池最大使用連接數量
spring.datasource.druid.max-active=20
#連接池最小空閑
spring.datasource.druid.min-idle=0
#獲取連接最大等待時間
spring.datasource.druid.max-wait=6000
spring.datasource.druid.validation-query=SELECT 1
#spring.datasource.druid.validation-query-timeout=6000
spring.datasource.druid.test-on-borrow=false
spring.datasource.druid.test-on-return=false
spring.datasource.druid.test-while-idle=true
#配置間隔多久才進行一次檢測，檢測需要關閉的空閑連接，單位是毫秒
spring.datasource.druid.time-between-eviction-runs-millis=60000
#置一個連接在池中最小生存的時間，單位是毫秒
spring.datasource.druid.min-evictable-idle-time-millis=25200000
#spring.datasource.druid.max-evictable-idle-time-millis=
#打開removeAbandoned功能,多少時間內必須關閉連接
spring.datasource.druid.removeAbandoned=true
#1800秒，也就是30分鐘
spring.datasource.druid.remove-abandoned-timeout=1800
#<!-- 1800秒，也就是30分鐘 -->
spring.datasource.druid.log-abandoned=true
spring.datasource.druid.filters=mergeStat

@Bean(initMethod = "init")
    @ConditionalOnMissingBean
    public DataSource dataSource() {
        LOGGER.info("Init DruidDataSource");
        return new DruidDataSourceWrapper();
    }

/**
     * @Bean：向IOC容器中註入一個Bean
     * @ConfigurationProperties：使得配置文件中以spring.datasource為前綴的屬性映射到Bean的屬性中
     * @return
     */
    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource dataSource(){
        //做一些其他的自定義配置，比如密碼加密等......
        return new DruidDataSource();
    }

<dependency>
     <groupId>org.mybatis.spring.boot</groupId>
     <artifactId>mybatis-spring-boot-starter</artifactId>
     <version>2.0.0</version>
</dependency>

@EnableConfigurationProperties(MybatisProperties.class)

mybatis.type-handlers-package=com.demo.typehandler
mybatis.configuration.map-underscore-to-camel-case=true

@Bean
  @ConditionalOnMissingBean
  public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {}

/**
     * 註入SqlSessionFactory
     */
    @Bean("sqlSessionFactory1")
    public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:/mapper/**/*.xml"));
        org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
        // 自動將數據庫中的下劃線轉換為駝峰格式
        configuration.setMapUnderscoreToCamelCase(true);
        configuration.setDefaultFetchSize(100);
        configuration.setDefaultStatementTimeout(30);
        sqlSessionFactoryBean.setConfiguration(configuration);
        return sqlSessionFactoryBean.getObject();
    }

@ConditionalOnSingleCandidate(DataSource.class)

@ConditionalOnSingleCandidate(DataSource.class)

private Map<Object, Object> targetDataSources;

protected abstract Object determineCurrentLookupKey();

/**
 * 使用ThreadLocal存儲切換數據源後的KEY
 */
public class DataSourceHolder {
    //線程  本地環境
    private static final ThreadLocal<String> dataSources = new InheritableThreadLocal();

    //設置數據源
    public static void setDataSource(String datasource) {
        dataSources.set(datasource);
    }
    //獲取數據源
    public static String getDataSource() {
        return dataSources.get();
    }

    //清除數據源
    public static void clearDataSource() {
        dataSources.remove();
    }
}

/**
 * 動態數據源，繼承AbstractRoutingDataSource
 */
public class DynamicDataSource extends AbstractRoutingDataSource {

    /**
     * 返回需要使用的數據源的key，將會按照這個KEY從Map獲取對應的數據源（切換）
     * @return
     */
    @Override
    protected Object determineCurrentLookupKey() {
        //從ThreadLocal中取出KEY
        return DataSourceHolder.getDataSource();
    }

    /**
     * 構造方法填充Map，構建多數據源
     */
    public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object, Object> targetDataSources) {
        //默認的數據源，可以作為主數據源
        super.setDefaultTargetDataSource(defaultTargetDataSource);
        //目標數據源
        super.setTargetDataSources(targetDataSources);
        //執行afterPropertiesSet方法，完成屬性的設置
        super.afterPropertiesSet();
    }
}

/**
 * 切換數據源的註解
 */
@Target(value = ElementType.METHOD)
@Retention(value = RetentionPolicy.RUNTIME)
@Documented
public @interface SwitchSource {
    /**
     * 默認切換的數據源KEY
     */
    String DEFAULT_NAME = "hisDataSource";

    /**
     * 需要切換到數據的KEY
     */
    String value() default DEFAULT_NAME;
}

@Aspect
//優先級要設置在事務切面執行之前
@Order(1)
@Component
@Slf4j
public class DataSourceAspect {
    @Pointcut("@annotation(SwitchSource)")
    public void pointcut() {
    }
    /**
     * 在方法執行之前切換到指定的數據源
     * @param joinPoint
     */
    @Before(value = "pointcut()")
    public void beforeOpt(JoinPoint joinPoint) {
        /*因為是對註解進行切面，所以這邊無需做過多判定，直接獲取註解的值，進行環繞，將數據源設置成遠方，然後結束後，清楚當前線程數據源*/
        Method method = ((MethodSignature) joinPoint.getSignature()).getMethod();
        SwitchSource switchSource = method.getAnnotation(SwitchSource.class);
        log.info("[Switch DataSource]:" + switchSource.value());
        DataSourceHolder.setDataSource(switchSource.value());
    }

    /**
     * 方法執行之後清除掉ThreadLocal中存儲的KEY，這樣動態數據源會使用默認的數據源
     */
    @After(value = "pointcut()")
    public void afterOpt() {
        DataSourceHolder.clearDataSource();
        log.info("[Switch Default DataSource]");
    }
}

/**
     * 創建動態數據源的SqlSessionFactory，傳入的是動態數據源
     * @Primary這個註解很重要，如果項目中存在多個SqlSessionFactory，這個註解一定要加上
     */
    @Primary
    @Bean("sqlSessionFactory2")
    public SqlSessionFactory sqlSessionFactoryBean(DynamicDataSource dynamicDataSource) throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dynamicDataSource);
        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:/mapper/**/*.xml"));
        org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
        configuration.setMapUnderscoreToCamelCase(true);
        configuration.setDefaultFetchSize(100);
        configuration.setDefaultStatementTimeout(30);
        sqlSessionFactoryBean.setConfiguration(configuration);
        return sqlSessionFactoryBean.getObject();
    }

/**
     * @Bean：向IOC容器中註入一個Bean
     * @ConfigurationProperties：使得配置文件中以spring.datasource為前綴的屬性映射到Bean的屬性中
     */
    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean("dataSource")
    public DataSource dataSource(){
        return new DruidDataSource();
    }

    /**
     * 向IOC容器中註入另外一個數據源
     * 全局配置文件中前綴是spring.datasource.his
     */
    @Bean(name = SwitchSource.DEFAULT_NAME)
    @ConfigurationProperties(prefix = "spring.datasource.his")
    public DataSource hisDataSource() {
        return DataSourceBuilder.create().build();
    }

/**
     * 創建動態數據源的SqlSessionFactory，傳入的是動態數據源
     * @Primary這個註解很重要，如果項目中存在多個SqlSessionFactory，這個註解一定要加上
     */
    @Primary
    @Bean("sqlSessionFactory2")
    public SqlSessionFactory sqlSessionFactoryBean(DynamicDataSource dynamicDataSource) throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dynamicDataSource);
        org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
        configuration.setMapUnderscoreToCamelCase(true);
        configuration.setDefaultFetchSize(100);
        configuration.setDefaultStatementTimeout(30);
        sqlSessionFactoryBean.setConfiguration(configuration);
        return sqlSessionFactoryBean.getObject();
    }

/**
     * 重寫事務管理器，管理動態數據源
     */
    @Primary
    @Bean(value = "transactionManager2")
    public PlatformTransactionManager annotationDrivenTransactionManager(DynamicDataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

//不開啟事務
    @Transactional(propagation = Propagation.NOT_SUPPORTED)
    //切換到HIS的數據源
    @SwitchSource
    @Override
    public List<DeptInfo> list() {
        return hisDeptInfoMapper.listDept();
    }