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()));
    }
}