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首先在配置文件中配置多个数据源
<!--数据库配置一-->
<bean id="dataSource1" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="${jdbc.driver}" />
<property name="url" value="${dataSource1.jdbc.conn.url}" />
<property name="username" value="${dataSource1.jdbc.conn.username}" />
<property name="password" value="${dataSource1.jdbc.conn.password}" />
<property name="initialSize" value="${jdbc.dbcp.initialSize}" />
<property name="minIdle" value="${dataSource1.jdbc.dbcp.minIdle}" />
<property name="maxIdle" value="${dataSource1.jdbc.dbcp.maxIdle}" />
<property name="maxActive" value="${dataSource1.jdbc.dbcp.maxActive}" />
<property name="maxWait" value="${jdbc.dbcp.maxWait}" />
</bean>
<!--数据库配置二-->
<bean id="dataSource2" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="${jdbc.driver}" />
<property name="url" value="${dataSource2.jdbc.conn.url}" />
<property name="username" value="${dataSource2.jdbc.conn.username}" />
<property name="password" value="${dataSource2.jdbc.conn.password}" />
<property name="initialSize" value="${jdbc.dbcp.initialSize}" />
<property name="minIdle" value="${dataSource2.jdbc.dbcp.minIdle}" />
<property name="maxIdle" value="${dataSource2.jdbc.dbcp.maxIdle}" />
<property name="maxActive" value="${dataSource2.jdbc.dbcp.maxActive}" />
<property name="maxWait" value="${jdbc.dbcp.maxWait}" />
</bean>
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自定义数据源MyDataSource ,用一个Map属性存储多个数据源,实现DataSource接口
public class MyDataSource implements DataSource {
private Map<String, DataSource> dataSourceMap = new HashMap();
public void setDataSourceMap(Map<String, DataSource> dataSourceMap) {
this.dataSourceMap = dataSourceMap;
}
public Connection getConnection() throws SQLException {
return this.getMyDataSource().getConnection();
}
public DataSource getMyDataSource() {
String which = MyDataSourceContext.getContext().getWhich();
if(StringUtils.equals(which, "dataSource1")) {
return (DataSource)this.dataSourceMap.get("dataSource1");
} else {
return (DataSource)this.dataSourceMap.get("dataSource2");
}
}
}
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加载自定义数据源,注入到数据库操作Session工厂
<!-- 自定义数据源 -->
<bean id="myDataSource" class="xxx.xxx.MyDataSource">
<property name="dataSourceMap">
<map>
<entry key="dataSource1" value-ref="dataSource1"></entry>
<entry key="dataSource2" value-ref="dataSource2"></entry>
</map>
</property>
</bean>
<!-- 数据库操作Session工厂 -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="myDataSource"/>
<property name="configLocation" value="classpath:/mybatis-config.xml"/>
<property name="mapperLocations" value="classpath:/sqlMap/*Mapper.xml"/>
</bean>
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用线程本地变量(ThreadLocal)来支持每个线程可选择自己的数据源
public class MyDataSourceContext {
private static final ThreadLocal<MyDataSourceContext> localContext = new ThreadLocal();
private String which = "dataSource2";
private MyDataSourceContext() {
localContext.set(this);
}
public String getWhich() {
return this.which;
}
public String setWhich(String which) {
this.which = which;
}
public static MyDataSourceContext getContext() {
MyDataSourceContext context = (MyDataSourceContext)localContext.get();
return context == null ? new MyDataSourceContext() : context;
}
}
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提供一个工具类,在每个线程执行数据库操作之前,用工具类来修改自己的数据源。
public class DatasourceUtils {
public static void switchDatasource(String datasource){
MyDataSourceContext.getContext().setWhich(datasource);
}
}
因为每个线程的本地变量localContext 存的是MyDataSourceContext 的实例,也就是说每个线程都有自己的MyDataSourceContext 实例,所以调用setWhich()方法可以修改线程内实例的which 属性值,这样在执行数据库操作时调用sqlSessionFactory中配置的dataSource(也就是myDataSource)的getConnection()时,根据线程的本地变量的属性值选择想要的数据源。