一、Springboot 动态数据源

把文章下半部分的代码复制到项目包中，然后按下面步骤处理就能实现多数据源的切换。

1、启动类注册动态数据源

@SpringBootApplication @Import({DynamicDataSourceRegister.class}) public class SpringBootSampleApplication {}

2、配置文件application.properties

#JDBC配置
#默认数据源
#spring.datasource.type=com.alibaba.druid.pool.DruidDataSource type可以修改连接池，默认采用Tomcat的连接池
spring.datasource.url=jdbc:mysql://localhost:3306/consult
spring.datasource.username=myConsult
spring.datasource.password=123456
spring.datasource.driver-class-name=org.gjt.mm.mysql.Driver
# 更多数据源 
custom.datasource.names=ds1,ds2 
custom.datasource.ds1.driver-class-name=com.mysql.jdbc.Driver
custom.datasource.ds1.url=jdbc:mysql://localhost:3306/test1
custom.datasource.ds1.username=root 
custom.datasource.ds1.password=123456 
custom.datasource.ds2.driver-class-name=com.mysql.jdbc.Driver 
custom.datasource.ds2.url=jdbc:mysql://localhost:3306/test2
custom.datasource.ds2.username=root 
custom.datasource.ds2.password=123456

3、配置文件中加上配置

mybatis.typeAliasesPackage=com.dongnao.jack.bean
mybatis.mapperLocations=classpath:com/dongnao/jack/xml/*Mapper.xml

补充：mybatis引入后mapper的映射接口不用添加注解，其他用法一样。

4、动态切换数据源

使用时用@TargetDataSource(name = “ds1”)指明数据源即可。

@TargetDataSource(name = "ds1")
public User findUserByName(String username) {
    List<User> users = userMapper.findByUserName(username);
    return users.size() > 0 ? users.get(0) : null;
}

@Transactional
@TargetDataSource(name = "ds2")
public int saveArea(ConsultConfigArea area) {
    int cout = mapper.saveArea(area);
    //        throw new RuntimeException();
    return cout;
}

下面贴上完整的处理代码：

1、DynamicDataSourceRegister

package com.dongnao.jack.dynamicDataSource;

import java.util.HashMap;
import java.util.Map;

import javax.sql.DataSource;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.PropertyValues;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.bind.RelaxedDataBinder;
import org.springframework.boot.bind.RelaxedPropertyResolver;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.support.DefaultConversionService;
import org.springframework.core.env.Environment;
import org.springframework.core.type.AnnotationMetadata;

public class DynamicDataSourceRegister implements
        ImportBeanDefinitionRegistrar, EnvironmentAware {
    private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceRegister.class);

    private ConversionService conversionService = new DefaultConversionService();

    private PropertyValues dataSourcePropertyValues;

    // 如配置文件中未指定数据源类型，使用该默认值
    private static final Object DATASOURCE_TYPE_DEFAULT = "org.apache.tomcat.jdbc.pool.DataSource";

    // private static final Object DATASOURCE_TYPE_DEFAULT =
    // "com.zaxxer.hikari.HikariDataSource";

    // 数据源
    private DataSource defaultDataSource;

    private Map<String, DataSource> customDataSources = new HashMap<String, DataSource>();

    public void registerBeanDefinitions(
            AnnotationMetadata importingClassMetadata,
            BeanDefinitionRegistry registry) {
        Map<Object, Object> targetDataSources = new HashMap<Object, Object>();
        // 将主数据源添加到更多数据源中
        targetDataSources.put("dataSource", defaultDataSource);
        DynamicDataSourceContextHolder.dataSourceIds.add("dataSource");
        // 添加更多数据源
        targetDataSources.putAll(customDataSources);
        for (String key : customDataSources.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);
        registry.registerBeanDefinition("dataSource", beanDefinition);

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

    /**
     * 创建DataSource
     *
     * @param type
     * @param driverClassName
     * @param url
     * @param username
     * @param password
     * @return
     * @author SHANHY
     * @create 2016年1月24日
     */
    @SuppressWarnings("unchecked")
    public DataSource buildDataSource(Map<String, Object> dsMap) {
        try {
            Object type = dsMap.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 = dsMap.get("driver-class-name").toString();
            String url = dsMap.get("url").toString();
            String username = dsMap.get("username").toString();
            String password = dsMap.get("password").toString();

            DataSourceBuilder factory = DataSourceBuilder.create()
                    .driverClassName(driverClassName)
                    .url(url)
                    .username(username)
                    .password(password)
                    .type(dataSourceType);
            return factory.build();
        }
        catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 加载多数据源配置
     */
    public void setEnvironment(Environment env) {
        initDefaultDataSource(env);
        initCustomDataSources(env);
    }

    /**
     * 初始化主数据源
     *
     * @author SHANHY
     * @create 2016年1月24日
     */
    private void initDefaultDataSource(Environment env) {
        // 读取主数据源
        RelaxedPropertyResolver propertyResolver = new RelaxedPropertyResolver(
                env, "spring.datasource.");
        Map<String, Object> dsMap = new HashMap<String, Object>();
        dsMap.put("type", propertyResolver.getProperty("type"));
        dsMap.put("driver-class-name",
                propertyResolver.getProperty("driver-class-name"));
        dsMap.put("url", propertyResolver.getProperty("url"));
        dsMap.put("username", propertyResolver.getProperty("username"));
        dsMap.put("password", propertyResolver.getProperty("password"));

        defaultDataSource = buildDataSource(dsMap);

        dataBinder(defaultDataSource, env);
    }

    /**
     * 为DataSource绑定更多数据
     *
     * @param dataSource
     * @param env
     * @author SHANHY
     * @create  2016年1月25日
     */
    private void dataBinder(DataSource dataSource, Environment env) {
        RelaxedDataBinder dataBinder = new RelaxedDataBinder(dataSource);
        //dataBinder.setValidator(new LocalValidatorFactory().run(this.applicationContext));
        dataBinder.setConversionService(conversionService);
        dataBinder.setIgnoreNestedProperties(false);//false
        dataBinder.setIgnoreInvalidFields(false);//false
        dataBinder.setIgnoreUnknownFields(true);//true
        if (dataSourcePropertyValues == null) {
            Map<String, Object> rpr = new RelaxedPropertyResolver(env,
                    "spring.datasource").getSubProperties(".");
            Map<String, Object> values = new HashMap<String, Object>(rpr);
            // 排除已经设置的属性
            values.remove("type");
            values.remove("driver-class-name");
            values.remove("url");
            values.remove("username");
            values.remove("password");
            dataSourcePropertyValues = new MutablePropertyValues(values);
        }
        dataBinder.bind(dataSourcePropertyValues);
    }

    /**
     * 初始化更多数据源
     *
     * @author SHANHY
     * @create 2016年1月24日
     */
    private void initCustomDataSources(Environment env) {
        // 读取配置文件获取更多数据源，也可以通过defaultDataSource读取数据库获取更多数据源
        RelaxedPropertyResolver propertyResolver = new RelaxedPropertyResolver(
                env, "custom.datasource.");
        String dsPrefixs = propertyResolver.getProperty("names");
        for (String dsPrefix : dsPrefixs.split(",")) {// 多个数据源
            Map<String, Object> dsMap = propertyResolver.getSubProperties(dsPrefix
                    + ".");
            DataSource ds = buildDataSource(dsMap);
            customDataSources.put(dsPrefix, ds);
            dataBinder(ds, env);
        }
    }
}

2、TargetDataSource

package com.dongnao.jack.dynamicDataSource;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {
    String name();
}

3、DynamicDataSource

package com.dongnao.jack.dynamicDataSource;

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

public class DynamicDataSource extends AbstractRoutingDataSource {

    @Override
    protected Object determineCurrentLookupKey() {
        // TODO Auto-generated method stub
        return DynamicDataSourceContextHolder.getDataSourceType();
    }
}

4、DynamicDataSourceAspect

package com.dongnao.jack.dynamicDataSource;

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.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Aspect
//保证该AOP在@Transactional之前执行
@Order(-1)
@Component
public class DynamicDataSourceAspect {
    private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceAspect.class);

    /** 
     * @Description 在方法执行之前执行  @annotation(ds) 会拦截有ds这个注解的方法即有 TargetDataSource这个注解的
     * @param @param point
     * @param @param ds
     * @param @throws Throwable 参数 
     * @return void 返回类型  
     * @throws 
     */
    @Before("@annotation(ds)")
    public void changeDataSource(JoinPoint point, TargetDataSource ds)
            throws Throwable {
        String dsId = ds.name();
        if (!DynamicDataSourceContextHolder.containsDataSource(dsId)) {
            logger.error("数据源[{}]不存在，使用默认数据源 > {}",
                    ds.name(),
                    point.getSignature());
        }
        else {
            logger.debug("Use DataSource : {} > {}",
                    ds.name(),
                    point.getSignature());
            DynamicDataSourceContextHolder.setDataSourceType(ds.name());
        }
    }

    /** 
     * @Description 在方法执行之后执行  @annotation(ds) 会拦截有ds这个注解的方法即有 TargetDataSource这个注解的 
     * @param @param point
     * @param @param ds 参数 
     * @return void 返回类型  
     * @throws 
     */

    @After("@annotation(ds)")
    public void restoreDataSource(JoinPoint point, TargetDataSource ds) {
        logger.debug("Revert DataSource : {} > {}",
                ds.name(),
                point.getSignature());
        DynamicDataSourceContextHolder.clearDataSourceType();
    }
}

5、DynamicDataSourceContextHolder

package com.dongnao.jack.dynamicDataSource;

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

public class DynamicDataSourceContextHolder {
    private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();

    public static List<String> dataSourceIds = new ArrayList<String>();

    public static void setDataSourceType(String dataSourceType) {
        contextHolder.set(dataSourceType);
    }

    public static String getDataSourceType() {
        return contextHolder.get();
    }

    public static void clearDataSourceType() {
        contextHolder.remove();
    }

    /**
     * 判断指定DataSrouce当前是否存在
     *
     * @param dataSourceId
     * @return
     * @author SHANHY
     * @create  2016年1月24日
     */
    public static boolean containsDataSource(String dataSourceId) {
        return dataSourceIds.contains(dataSourceId);
    }
}