baomidou的dynamic-datasource读写分离实现和加入AOP根据方法名选择库

Java基础

浏览数:109

2020-7-7


文档

https://gitee.com/baomidou/dynamic-datasource-spring-boot-starter/wikis/pages

maven

        <dependency>
			<groupId>com.baomidou</groupId>
			<artifactId>dynamic-datasource-spring-boot-starter</artifactId>
			<version>2.5.7</version>
		</dependency>

纯读写分离(mybatis环境)

场景:

  1. 在纯的读写分离环境,写操作全部是master,读操作全部是slave。
  2. 不想通过注解配置完成以上功能。

答:在mybatis环境下可以基于mybatis插件结合本数据源完成以上功能。 手动注入插件。

@Bean
public MasterSlaveAutoRoutingPlugin masterSlaveAutoRoutingPlugin(){
    return new MasterSlaveAutoRoutingPlugin();
}

默认主库名称master,从库名称slave。

问题

       我在配置好了之后,调试发现对数据库读的操作不得进入MasterSlaveAutoRoutingPlugin,而且进入了默认的库。只有写进入了MasterSlaveAutoRoutingPlugin中。当然也可以默认为从库,但是感觉就不是很好。

       于是我自定义了一个aop切面来,来完成库的选择,代码如下:

import java.lang.reflect.Method;
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.springframework.context.annotation.Lazy;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import com.baomidou.dynamic.datasource.annotation.DS;
import com.baomidou.dynamic.datasource.toolkit.DynamicDataSourceContextHolder;
import lombok.extern.java.Log;

/**
 * Copyright: Copyright (c) 2019
 * <p> 说明:动态数据源配置 </P>
 * 
 * @version: V1.0
 * @author: BianPeng
 * 
 */
@Aspect
@Component
@Order(0)
@Lazy(false)
@Log
public class DataSourceAop{

	private static final String MASTER = "master";

	private static final String SLAVE = "slave";

	
	@Pointcut("execution(* com.buybit.power.service..*.*(..)) || execution(* com.baomidou.mybatisplus.extension.service..*.*(..))")
    public void checkArgs() {
    }
	
	// 这里切到你的方法目录
	@Before("checkArgs()")
	public void process(JoinPoint joinPoint) throws NoSuchMethodException, SecurityException {
		String methodName = joinPoint.getSignature().getName();
		if (methodName.startsWith("get") 
                || methodName.startsWith("count") 
                || methodName.startsWith("find")
				|| methodName.startsWith("list") 
                || methodName.startsWith("select") 
                || methodName.startsWith("check")
				|| methodName.startsWith("page")) {

			log.info("当前执行的库:"+SLAVE);
			DynamicDataSourceContextHolder.push(SLAVE);
		} else {
			log.info("当前执行的库:"+MASTER);
			DynamicDataSourceContextHolder.push(MASTER);
		}
	}
	@After("checkArgs()")
    public void afterAdvice(){
        DynamicDataSourceContextHolder.clear();
    }
}

但是发现,baomidou/dynamic-datasource自带的@DS没失去了着用,于是我把有@DS的类和方法排除掉,代码入下:

import java.lang.reflect.Method;
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.springframework.context.annotation.Lazy;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import com.baomidou.dynamic.datasource.annotation.DS;
import com.baomidou.dynamic.datasource.toolkit.DynamicDataSourceContextHolder;
import lombok.extern.java.Log;

/**
 * Copyright: Copyright (c) 2019
 * <p> 说明:动态数据源配置 </P>
 * 
 * @version: V1.0
 * @author: BianPeng
 * 
 */
@Aspect
@Component
@Order(0)
@Lazy(false)
@Log
public class DataSourceAop{

	private static final String MASTER = "master";

	private static final String SLAVE = "slave";

	
	@Pointcut("execution(* com.buybit.power.service..*.*(..)) || execution(* com.baomidou.mybatisplus.extension.service..*.*(..))")
    public void checkArgs() {
    }
	
	// 这里切到你的方法目录
	@Before("checkArgs()")
	public void process(JoinPoint joinPoint) throws NoSuchMethodException, SecurityException {
		String methodName = joinPoint.getSignature().getName();
        Class clazz = joinPoint.getTarget().getClass();
		if(clazz.isAnnotationPresent(DS.class)){
		    //获取类上注解
			return;
		} 
		
	    String targetName = clazz.getSimpleName();
	    Class[] parameterTypes = 
        ((MethodSignature)joinPoint.getSignature()).getMethod().getParameterTypes();
	    Method methdo = clazz.getMethod(methodName,parameterTypes);
	    if (methdo.isAnnotationPresent(DS.class)) {
	    	return;
	    }
		if (methodName.startsWith("get") 
                || methodName.startsWith("count") 
                || methodName.startsWith("find")
				|| methodName.startsWith("list") 
                || methodName.startsWith("select") 
                || methodName.startsWith("check")
				|| methodName.startsWith("page")) {

			log.info("当前执行的库:"+SLAVE);
			DynamicDataSourceContextHolder.push(SLAVE);
		} else {
			log.info("当前执行的库:"+MASTER);
			DynamicDataSourceContextHolder.push(MASTER);
		}
	}
	@After("checkArgs()")
    public void afterAdvice(){
        DynamicDataSourceContextHolder.clear();
    }
}

这样可以让你有@DS的注解依然生效,而且也会根据方法名来自动切换数据源。

作者:KINBUG-BP