动态更改Spring数据源 [英] dynamically change Spring data source

问题描述

我有一个Spring应用程序，我想动态更改数据源，即。当输入DS URL时，Spring bean和所有依赖项将自动更新。我知道这有点奇怪，但无论如何我想实现这一点。
My Spring配置如下：

I have a Spring application, i want to change the data source dynamically,ie. when input a DS URL, the Spring beans and all dependency will get updated automatically.I know this is somewhat strange, but anyway i want to achieve that. My Spring configuration as following:

<bean id="majorDataSource" class="org.postgresql.ds.PGSimpleDataSource">
    <property name="serverName" value="${jdbc.serverName}" />
    <property name="portNumber" value="${jdbc.portNumber}" />
    <property name="user" value="${jdbc.username}" />
    <property name="password" value="${jdbc.password}" />
    <property name="databaseName" value="${jdbc.databaseName}" />
</bean>
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="majorDataSource"/>
</bean>

<tx:annotation-driven transaction-manager="transactionManager"/>

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="majorDataSource"/>
    <property name="configLocation" value="classpath:sqlmap-config.xml"/>
</bean>

问题是：

1. JDBC URL存储在属性中，可以在运行时更改。

1. The JDBC URL is stored in properties, which could be changed runtime.

更改URL后，我需要重新启动 - 创建数据源，也可以创建依赖对象。我无法弄清楚如何在Spring中优雅地做到这一点？

Once the URL is changed, i need to re-create the data source and maybe the dependent objects. I could not figure out how to do it elegantly in Spring?

我知道Spring确实可以动态路由数据源基于一个键，但数据源URL是在Spring中预定义的，不会更改运行时。这不是我的情况。

I have known that Spring did could dynamically route data source based on one key, but the data source URL is predefined in Spring and will not change runtime. It is not my case.

推荐答案

你可以使用spring的 AbstractRoutingDataSource 通过扩展它并覆盖方法 determineCurrentLookupKey（）应该返回引用要使用的数据源的spring bean的键。

You can use spring's AbstractRoutingDataSource by extending it and overriding the method determineCurrentLookupKey() that should return the key referencing the datasource's spring bean to be used.

看看这个关于spring source博客的博客文章，它将向您展示如何使用该功能的示例。

Take a look at this blog article on spring source's blog which will show you an example of how to use that feature.

基本上回答你的问题，你需要做的是在XML配置中将两个数据源定义为不同的spring bean。无需动态创建一个，spring将同时加载两个，并根据 determineCurrentLookupKey（）方法中的条件动态使用其中一个。

Basically to answer your questions, what you will need to do is to define the two datasources as different spring bean in your XML config. There is no need to create one dynamically, spring will load both, and use one or the other dynamically depending on your criteria in the determineCurrentLookupKey() method.

这会导致类似：

XML配置

<!-- first data source -->
<bean id="majorDataSource" class="org.postgresql.ds.PGSimpleDataSource">
    <property name="serverName" value="${jdbc.major.serverName}" />
    <property name="portNumber" value="${jdbc.major.portNumber}" />
    <property name="user" value="${jdbc.major.username}" />
    <property name="password" value="${jdbc.major.password}" />
    <property name="databaseName" value="${jdbc.major.databaseName}" />
</bean>
<!-- second data source -->
<bean id="minorDataSource" class="org.postgresql.ds.PGSimpleDataSource">
    <property name="serverName" value="${jdbc.minor.serverName}" />
    <property name="portNumber" value="${jdbc.minor.portNumber}" />
    <property name="user" value="${jdbc.minor.username}" />
    <property name="password" value="${jdbc.minor.password}" />
    <property name="databaseName" value="${jdbc.minor.databaseName}" />
</bean>
<!-- facade data source -->
<bean id="dataSource" class="blog.datasource.CustomerRoutingDataSource">
   <property name="targetDataSources">
      <map>
         <entry key="MINOR" value-ref="minorDataSource"/>
         <entry key="MAJOR" value-ref="majorDataSource"/>
      </map>
   </property>
   <property name="defaultTargetDataSource" ref="majorDataSource"/>
</bean>
<!-- wiring up -->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dataSource"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <property name="configLocation" value="classpath:sqlmap-config.xml"/>
</bean>

Java

public class MyRoutingDataSource extends AbstractRoutingDataSource {
   @Override
   protected Object determineCurrentLookupKey() {
      // get the current url
      HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest();
      if (request.getRequestURL().toString().endsWith("/minor"))
          return "MINOR";
      else
          return "MAJOR";
   }
}

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