# :-: 自定义负载均衡策略 # 自定义负载均衡策略 ## 基础介绍 如下图`slave`组下有三个数据源，当用户使用`slave`切换数据源时会使用负载均衡算法。 系统自带了两个负载均衡算法 * `LoadBalanceDynamicDataSourceStrategy`轮询,是默认的。 * `RandomDynamicDataSourceStrategy`随机的。 ~~~ spring: datasource: dynamic: datasource: master: username: sa password: "" url: jdbc:h2:mem:test driver-class-name: org.h2.Driver schema: db/schema.sql slave_1: username: sa password: "" url: jdbc:h2:mem:test driver-class-name: org.h2.Driver slave_2: username: sa password: "" url: jdbc:h2:mem:test driver-class-name: org.h2.Driver slave_3: username: sa password: "" url: jdbc:h2:mem:test driver-class-name: org.h2.Driver strategy: com.baomidou.dynamic.datasource.strategy.LoadBalanceDynamicDataSourceStrategy ~~~ ## 如何自定义 如果默认的两个都不能满足要求，可以参考源码自定义。 暂时只能全局更改。 ~~~ import java.util.List; import java.util.concurrent.ThreadLocalRandom; import javax.sql.DataSource; public class RandomDynamicDataSourceStrategy implements DynamicDataSourceStrategy { public RandomDynamicDataSourceStrategy() { } public DataSource determineDataSource(List<DataSource> dataSources) { return (DataSource)dataSources.get(ThreadLocalRandom.current().nextInt(dataSources.size())); } } ~~~