springboot中Druid多数据源配置

1.application.properties配置如下：

#数据源1
spring.jdbc.datasource.ds1.driver-class-name=com.mysql.jdbc.Driver
spring.jdbc.datasource.ds1.url=jdbc:mysql://localhost:3306/test?zeroDateTimeBehavior=convertToNull&allowMultiQueries=true
spring.jdbc.datasource.ds1.username=root
spring.jdbc.datasource.ds1.password=root
spring.jdbc.datasource.ds1.type = com.alibaba.druid.pool.DruidDataSource

###########################################################
#数据源2
spring.jdbc.datasource.ds2.driver-class-name=com.mysql.jdbc.Driver
spring.jdbc.datasource.ds2.url=jdbc:mysql://localhost:3307/test?zeroDateTimeBehavior=convertToNull&allowMultiQueries=true
spring.jdbc.datasource.ds2.username=root
spring.jdbc.datasource.ds2.password=root
spring.jdbc.datasource.ds2.type = com.alibaba.druid.pool.DruidDataSource

2.加载数据源

@Configuration
@Slf4j
public class DataSourceConfig {
    @Bean("springDataSource1")
    @ConfigurationProperties("spring.jdbc.datasource.ds1")
    public DataSource springDataSource(){
        DataSource dataSource  = DruidDataSourceBuilder.create().build();
        return dataSource;
    }

    @Bean("springDataSource2")
    @ConfigurationProperties("spring.jdbc.datasource.ds2")
    public DataSource springDataSource(){
        DataSource dataSource  = DruidDataSourceBuilder.create().build();
        return dataSource;
    }
}

3.动态数据源配置

@Configuration
public class DynamicTransactionManager {

    @Autowired
    @Qualifier("springDataSource1")
    private DataSource springDataSource1;

    @Autowired
    @Qualifier("springDataSource2")
    private DataSource springDataSource2;

    @Bean
    public DynamicDataSource dataSource(){
        //按照目标数据源名称和目标数据源对象的映射存放在Map中
        Map targetDataSources = new HashMap<>();
        targetDataSources.put("springDataSource1",springDataSource1);
        targetDataSources.put("springDataSource2",springDataSource2);

        DynamicDataSource dataSource = new DynamicDataSource();
        dataSource.setTargetDataSources(targetDataSources);
        //设置默认的数据源，当拿不到数据源时，使用此配置
        dataSource.setDefaultTargetDataSource(springDataSource1);
        return dataSource;
    }

    @Bean
    public PlatformTransactionManager txManager(DataSource dataSource){
        return new DataSourceTransactionManager(dataSource);
    }
}

4.动态数据源路由

public class DynamicDataSource extends AbstractRoutingDataSource {
    /**
     * 数据源路由，此方法用于产生要选取的数据源逻辑名称
     * @return
     */
    @Override
    protected Object determineCurrentLookupKey() {
        //从共享线程中获取数据源名称
        return DynamicDataSourceHolder.getDataSource();
    }
}

public class DynamicDataSourceHolder {
    /**
     * 本地线程共享对象
     */
    private static final ThreadLocal THREAD_LOCAL = new ThreadLocal<>();

    public static void putDataSource(String name){
        THREAD_LOCAL.set(name);
    }

    public static String getDataSource(){
        return THREAD_LOCAL.get();
    }

    public static void removeDataSource(){
        if(THREAD_LOCAL.get() != null)
            THREAD_LOCAL.remove();
    }
}

5.配置注解

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface TargetDataSource {
    String value() default "shardingDataSource";    //此处接收的是数据源名称
}

6.配置切面

@Component
@Aspect
@Order(1)
@Slf4j
public class DataSourceAspect {
    //切换放在mapper接口的方法上，所以这里要配置AOP切面的切入点
    @Pointcut("@annotation(TargetDataSource)")
    public void dataSourcePointCut(){

    }
    @Before("dataSourcePointCut()")
    public void before(JoinPoint joinPoint){
        Object target = joinPoint.getTarget();
        String method = joinPoint.getSignature().getName();
        Class clazz = target.getClass();
        Class[] parameterTypes = ((MethodSignature)joinPoint.getSignature()).getMethod().getParameterTypes();
        try{
            Method m = clazz.getMethod(method,parameterTypes);
            //如果方法上存在切换数据源的注解，则根据注解内容进行数据源切换
            if(m!=null && m.isAnnotationPresent(TargetDataSource.class) && DynamicDataSourceHolder.getDataSource() == null){
                TargetDataSource data = m.getAnnotation(TargetDataSource.class);
                String dataSourceName = data.value();

                DynamicDataSourceHolder.putDataSource(dataSourceName);
                log.debug("current thread "+Thread.currentThread().getName()+" add data to ThreadLocal");
            }else{
                log.debug("switch datasource fail, use default");
            }
        }catch (Exception e){
            log.error("current thread "+Thread.currentThread().getName()+" add data to ThreadLocal error",e);
        }
    }

    //执行完切面后，将线程共享中的数据源名称清空
    @After("dataSourcePointCut()")
    public void after(JoinPoint joinPoint){
        DynamicDataSourceHolder.removeDataSource();
    }
}