springboot2.0动态多数据源切换

2018-06-27 09:45:18来源：博客园阅读 ()

摘要：springboot1.x到springboot2.0配置变化有一点变化，网上关于springboot2.0配置多数据源的资料也比较少，为了让大家配置多数据源从springboot1.x升级到springboot2.0少踩写坑，博主在此介绍用springboot2.0来进行动态数据源切换。（在博客的最后会给大家提供源码的下载地址）

一、引入依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.heshouyou</groupId>
    <artifactId>dynamic-datasource</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>dynamic-datasource</name>
    <description>dynamic-datasource project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

二、编辑application.yml

server.port=8080
#数据源配置（默认）
#useSSL=false MySQL在高版本需要指明是否进行SSL连接（不加第一次连接数据库会有警告信息）
spring.datasource.driver=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/test?useSSL=false
spring.datasource.username=root
spring.datasource.password=123456
#ds1,ds2 其他两个数据源
slave.datasource.names=ds1,ds2
#ds1
slave.datasource.ds1.driver=com.mysql.jdbc.Driver
slave.datasource.ds1.url=jdbc:mysql://localhost:3306/test1?useSSL=false
slave.datasource.ds1.username=root
slave.datasource.ds1.password=123456
#ds2
slave.datasource.ds2.driver=com.mysql.jdbc.Driver
slave.datasource.ds2.url=jdbc:mysql://localhost:3306/test2?useSSL=false
slave.datasource.ds2.username=root
slave.datasource.ds2.password=123456
#mapper.xml文件
mybatis.mapper-locations=classpath:mapper/*.xml
#实体类包
mybatis.type-aliases-package=datasource.springboot_datasource.entity

三、DataSource工具类

动态切换类

package com.chaoqi.springboot_datasource.config;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

/**
 * @Author caiChaoqi
 * @Date 2018-06-23
 * @Description 动态数据源
 * AbstractRoutingDataSource(每执行一次数据库，动态获取DataSource)
 */
public class DynamicDataSource extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        return DynamicDataSourceContextHolder.getDataSourceType();
    }
}

动态数据源上下文管理

package com.chaoqi.springboot_datasource.config;

import org.apache.log4j.Logger;

import java.util.ArrayList;
import java.util.List;

/**
 * @Author caiChaoqi
 * @Date 2018-06-23
 * @Description 动态数据源上下文管理
 */
public class DynamicDataSourceContextHolder {

    private Logger logger = Logger.getLogger(DynamicDataSourceContextHolder.class);
    //存放当前线程使用的数据源类型信息
    private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
    //存放数据源id
    public static List<String> dataSourceIds = new ArrayList<String>();

    //设置数据源
    public static void setDataSourceType(String dataSourceType) {
        contextHolder.set(dataSourceType);
    }

    //获取数据源
    public static String getDataSourceType() {
        return contextHolder.get();
    }

    //清除数据源
    public static void clearDataSourceType() {
        contextHolder.remove();
    }

    //判断当前数据源是否存在
    public static boolean isContainsDataSource(String dataSourceId) {
        return dataSourceIds.contains(dataSourceId);
    }
}

初始化数据源和提供了执行动态切换数据源的工具类

package com.chaoqi.springboot_datasource.config;

import org.apache.log4j.Logger;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.env.Environment;
import org.springframework.core.type.AnnotationMetadata;

import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

/**
 * @Author caiChaoqi
 * @Date 2018-06-23
 * @Description 注册动态数据源
 * 初始化数据源和提供了执行动态切换数据源的工具类
 * EnvironmentAware（获取配置文件配置的属性值）
 */

public class DynamicDataSourceRegister implements ImportBeanDefinitionRegistrar, EnvironmentAware {

    private Logger logger = Logger.getLogger(DynamicDataSourceRegister.class);

    //指定默认数据源(springboot2.0默认数据源是hikari如何想使用其他数据源可以自己配置)
    private static final String DATASOURCE_TYPE_DEFAULT = "com.zaxxer.hikari.HikariDataSource";
    //默认数据源
    private DataSource defaultDataSource;
    //用户自定义数据源
    private Map<String, DataSource> slaveDataSources = new HashMap<>();

    @Override
    public void setEnvironment(Environment environment) {
        initDefaultDataSource(environment);
        initslaveDataSources(environment);
    }

    private void initDefaultDataSource(Environment env) {
        // 读取主数据源
        Map<String, Object> dsMap = new HashMap<>();
        dsMap.put("driver", env.getProperty("spring.datasource.driver"));
        dsMap.put("url", env.getProperty("spring.datasource.url"));
        dsMap.put("username", env.getProperty("spring.datasource.username"));
        dsMap.put("password", env.getProperty("spring.datasource.password"));
        defaultDataSource = buildDataSource(dsMap);
    }


    private void initslaveDataSources(Environment env) {
        // 读取配置文件获取更多数据源
        String dsPrefixs = env.getProperty("slave.datasource.names");
        for (String dsPrefix : dsPrefixs.split(",")) {
            // 多个数据源
            Map<String, Object> dsMap = new HashMap<>();
            dsMap.put("driver", env.getProperty("slave.datasource." + dsPrefix + ".driver"));
            dsMap.put("url", env.getProperty("slave.datasource." + dsPrefix + ".url"));
            dsMap.put("username", env.getProperty("slave.datasource." + dsPrefix + ".username"));
            dsMap.put("password", env.getProperty("slave.datasource." + dsPrefix + ".password"));
            DataSource ds = buildDataSource(dsMap);
            slaveDataSources.put(dsPrefix, ds);
        }
    }

    @Override
    public void registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry beanDefinitionRegistry) {
        Map<Object, Object> targetDataSources = new HashMap<Object, Object>();
        //添加默认数据源
        targetDataSources.put("dataSource", this.defaultDataSource);
        DynamicDataSourceContextHolder.dataSourceIds.add("dataSource");
        //添加其他数据源
        targetDataSources.putAll(slaveDataSources);
        for (String key : slaveDataSources.keySet()) {
            DynamicDataSourceContextHolder.dataSourceIds.add(key);
        }

        //创建DynamicDataSource
        GenericBeanDefinition beanDefinition = new GenericBeanDefinition();
        beanDefinition.setBeanClass(DynamicDataSource.class);
        beanDefinition.setSynthetic(true);
        MutablePropertyValues mpv = beanDefinition.getPropertyValues();
        mpv.addPropertyValue("defaultTargetDataSource", defaultDataSource);
        mpv.addPropertyValue("targetDataSources", targetDataSources);
        //注册 - BeanDefinitionRegistry
        beanDefinitionRegistry.registerBeanDefinition("dataSource", beanDefinition);

        logger.info("Dynamic DataSource Registry");
    }

    public DataSource buildDataSource(Map<String, Object> dataSourceMap) {
        try {
            Object type = dataSourceMap.get("type");
            if (type == null) {
                type = DATASOURCE_TYPE_DEFAULT;// 默认DataSource
            }
            Class<? extends DataSource> dataSourceType;
            dataSourceType = (Class<? extends DataSource>) Class.forName((String) type);
            String driverClassName = dataSourceMap.get("driver").toString();
            String url = dataSourceMap.get("url").toString();
            String username = dataSourceMap.get("username").toString();
            String password = dataSourceMap.get("password").toString();
            // 自定义DataSource配置
            DataSourceBuilder factory = DataSourceBuilder.create().driverClassName(driverClassName).url(url)
                    .username(username).password(password).type(dataSourceType);
            return factory.build();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }
}

自定义注解

package com.chaoqi.springboot_datasource.config;

import java.lang.annotation.*;

/**
 * @Author caiChaoqi
 * @Date 2018-06-23
 * @Description 作用于类、接口或者方法上
 */
@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {

    String name();
}

动态数据源通知

package com.chaoqi.springboot_datasource.config;

import org.apache.log4j.Logger;
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.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

/**
 * @Author caiChaoqi
 * @Description 动态数据源通知
 * @Date 2018-06-23
 */
@Aspect
@Order(-1)//保证在@Transactional之前执行
@Component
public class DynamicDattaSourceAspect {

    private Logger logger = Logger.getLogger(DynamicDattaSourceAspect.class);

    //改变数据源
    @Before("@annotation(targetDataSource)")
    public void changeDataSource(JoinPoint joinPoint, TargetDataSource targetDataSource) {
        String dbid = targetDataSource.name();

        if (!DynamicDataSourceContextHolder.isContainsDataSource(dbid)) {
            //joinPoint.getSignature() ：获取连接点的方法签名对象
            logger.error("数据源 " + dbid + " 不存在使用默认的数据源 -> " + joinPoint.getSignature());
        } else {
            logger.debug("使用数据源：" + dbid);
            DynamicDataSourceContextHolder.setDataSourceType(dbid);
        }
    }

    @After("@annotation(targetDataSource)")
    public void clearDataSource(JoinPoint joinPoint, TargetDataSource targetDataSource) {
        logger.debug("清除数据源 " + targetDataSource.name() + " !");
        DynamicDataSourceContextHolder.clearDataSourceType();
    }
}