spring管理数据源的动态更换

    
    
    
    <bean id="dataSource" class="com.chnedu.common.util.MultiDataSource">
        <property name="dataSource" ref="dataSource_a"/><!-- 默认连接数据库a -->
    </bean>	

    






import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.SQLException;

import javax.sql.DataSource;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;


public class MultiDataSource implements DataSource,ApplicationContextAware{
    private ApplicationContext applicationContext=null;
    private DataSource dataSource = null;
	
	@Override
	public PrintWriter getLogWriter() throws SQLException {
		return getDataSource().getLogWriter();
	}

	@Override
	public int getLoginTimeout() throws SQLException {
		return getDataSource().getLoginTimeout();
	}

	@Override
	public void setLogWriter(PrintWriter arg0) throws SQLException {
		getDataSource().setLogWriter(arg0);
	}

	@Override
	public void setLoginTimeout(int arg0) throws SQLException {
		getDataSource().setLoginTimeout(arg0);
	}

	@Override
	public boolean isWrapperFor(Class<?> arg0) throws SQLException {
		return getDataSource().isWrapperFor(arg0);
	}

	@Override
	public <T> T unwrap(Class<T> arg0) throws SQLException {
		return getDataSource().unwrap(arg0);
	}

	@Override
	public void setApplicationContext(ApplicationContext arg0)
			throws BeansException {
		this.applicationContext = arg0;
	}

	@Override
	public Connection getConnection() throws SQLException {
		return getDataSource().getConnection();
	}

	@Override
	public Connection getConnection(String arg0, String arg1)
			throws SQLException {
		return getDataSource().getConnection(arg0, arg1);
	}
    
	public DataSource getDataSource() {
		//根据session 中变量更换数据源
		Object siteId = StrutsUtil.getSession().get( Constants.SESSION_SITE_ID  );
		if(siteId==null || "".equals( siteId)){
			return dataSource;
		}else if( Constants.ACC_SITE_ID.equals( siteId)){
			dataSource = (DataSource) this.applicationContext.getBean("dataSource_a"); 
		}else {
			dataSource = (DataSource) this.applicationContext.getBean( "dataSource_b") ;
		}
		return dataSource;
	}

	public void setDataSource(DataSource dataSource) {
		this.dataSource = dataSource;
	}
 

}