其实这里介绍的东西主要是参考的另外一篇文章，数据库读写分离的。
参考文章就把链接贴出来，里面有那位的代码，简单明了https://gitee.com/comven/dynamic-datasource-demo?spm=5176.100239.blogcont188540.13.iARYDh。
这块内容前前后后总共写了三篇
1. Spring Boot HikariCP 一 ——集成多数据源
2. Spring Boot 动态切换数据源二——负载均衡
3. Spring Boot 动态切换数据源三——动态获取配置文件中的配置信息
4. 插件GitHubrhettpang/dynamic-datasource
读写分离的功能我已经使用replication集成好了，因为我们需要单独设置每个数据源的链接属性，而且使用的还是Hikari数据源，所以又在网上找了两天，最终昨天晚上发现了这种方式。
我这里说说自己集成的时候的一些注意点。
配置文件：
hikari:
master:
jdbc-url: jdbc:mysql://masterhost:3306/testdb?useUnicode=true&characterEncoding=utf8&useSSL=true&allowMultiQueries=true&verifyServerCertificate=false
username: root
password: root
maximum-pool-size: 20
pool-name: master
connection-timeout: 30000
idle-timeout: 600000
max-lifetime: 1765000
slave:
jdbc-url: jdbc:mysql://slavehost:3306/testdb?useUnicode=true&characterEncoding=utf8&useSSL=true&allowMultiQueries=true&verifyServerCertificate=false
username: root
password: root
maximum-pool-size: 80
pool-name: slave
connection-timeout: 30000
idle-timeout: 600000
max-lifetime: 1765000
read-only: true
我这里主要用到的是maximum-pool-size这个值，一般情况下读数据库（slave）总会比写（master）要多一些，而且往往是一个master多个slave。所以，maximum-pool-size这个值在master的设置小于slave比较高效。
import com.zaxxer.hikari.HikariDataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
/**
* @author Created by pangkunkun on 2017/12/18.
*/
@Component
@ConfigurationProperties(prefix = "hikari")
public class DBProperties {
private HikariDataSource master;
private HikariDataSource slave;
public HikariDataSource getMaster() {
return master;
}
public void setMaster(HikariDataSource master) {
this.master = master;
}
public HikariDataSource getSlave() {
return slave;
}
public void setSlave(HikariDataSource slave) {
this.slave = slave;
}
}
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.transaction.PlatformTransactionManager;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
/**
* @author Created by pangkunkun on 2017/12/18.
*/
@Configuration
@EnableScheduling
public class DataSourceConfig {
@Autowired
private DBProperties properties;
@Bean(name = "dataSource")
public DataSource 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<Object, Object> targetDataSources = new HashMap<>();
targetDataSources.put("master", properties.getMaster());
targetDataSources.put("slave", properties.getSlave());
//采用是想AbstractRoutingDataSource的对象包装多数据源
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(properties.getMaster());
return dataSource;
}
@Bean
public PlatformTransactionManager txManager() {
return new DataSourceTransactionManager(dataSource());
}
}
import com.easyar.cloud.cms.common.util.TargetDataSource;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import java.lang.reflect.Method;
/**
* @author Created by pangkunkun on 2017/12/18.
*/
@Component
@Aspect
public class DataSourceAspect {
private final static Logger log= LoggerFactory.getLogger(DataSourceAspect.class);
//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("execution( * com.easyar.cloud.cms.dao.mapper.*.*(..))||execution( * com.easyar.cloud.cms.shiro.mapper.*.*(..))")
public void dataSourcePointCut() {
}
@Before("dataSourcePointCut()")
public void before(JoinPoint joinPoint) {
Object target = joinPoint.getTarget();
String method = joinPoint.getSignature().getName();
Class<?>[] clazz = target.getClass().getInterfaces();
Class<?>[] parameterTypes = ((MethodSignature) joinPoint.getSignature()).getMethod().getParameterTypes();
try {
Method m = clazz[0].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)) {
TargetDataSource data = m.getAnnotation(TargetDataSource.class);
String dataSourceName = data.value();
DynamicDataSourceHolder.putDataSource(dataSourceName);
log.debug("current thread " + Thread.currentThread().getName() + " add " + dataSourceName + " 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();
}
}
原文：https://blog.csdn.net/qq_35981283/article/details/78846892