Springbooot +Mybaties 配置数据库多数据源

前言

在实际项目中，我们可能会碰到在一个项目中会访问多个数据库的情况。针对这种情况，我们就需要配置动态的数据源了。一般按照以下步骤即可

一、在启动类上添加注解

二、在application.properties文件中

#默认数据源

spring.datasource.driver-class-name= com.mysql.jdbc.Driver
spring.datasource.url = jdbc:mysql://127.0.0.1:3306/tianxi_mall?useUnicode=true&characterEncoding=UTF8&serverTimezone=GMT%2B8&allowMultiQueries=true

spring.datasource.username = root
spring.datasource.password =

#其他数据源.sqlserver
custom.datasource.names = ds1
custom.datasource.ds1.driver-class-name = com.mysql.jdbc.Driver
custom.datasource.ds1.url = jdbc:mysql://192.168.2.2:3306/wechat?useUnicode=true&characterEncoding=UTF8&serverTimezone=GMT%2B8&allowMultiQueries=true
custom.datasource.ds1.username = root
custom.datasource.ds1.password =

注：假如其他的数据源不是mysql，请自行百度其他数据的连接驱动

三、配置

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

/**
* AbstractRoutingDataSource获取数据源之前会先调用determineCurrentLookupKey方法查找当前的lookupKey，这个lookupKey就是数据源标识。
因此通过重写这个查找数据源标识的方法就可以让spring切换到指定的数据源了
* @author mayn
*
*/
public class DynamicDataSource extends AbstractRoutingDataSource{
protected Object determineCurrentLookupKey() {
//从自定义位置获取数据源标识
return DynamicDataSourceContextHolder.getDataSourceType();
}
}

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

@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());
}
}

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

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

/**
* 用于持有当前线程中使用的数据源标识
* @author mayn
*
*/
public class DynamicDataSourceContextHolder {
private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
public static List<String> dataSourceIds = new ArrayList<>();

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 * */
public static boolean containsDataSource(String dataSourceId){
return dataSourceIds.contains(dataSourceId);
}
}

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<>();

@Override
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<>();
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<>(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);
}
}
}

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;

/**
* 自定义注解
* @author mayn
*
*/
@Target({ElementType.METHOD, ElementType.TYPE })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {
String name();
}

四、配置完成后，只需在要切换数据源的映射接口上添加注解@TargetDataSource(name="ds1") 即可。注意，ds1是自定义的，对应了配置application.properties中的ds1，如下

/**
* 切换数据源查询
*/
@TargetDataSource(name="ds1")
public List<CardInfoResponse> cardInfo(String card_id) {
return cardMapper.cardInfo(card_id);
}

五、至此，完成，亲测有效。假如需要拓展更多的数据源，则相应继续往下配置即可。