java多数据源切换

开发中会出现多数据源切换的需求，
方案1：
jdbc方式，建立多个数据源连接

private static String driver;

	private static String url;

	private static String username;

	private static String password;

	static {
		try {
			Properties props = new Properties();
			InputStream is = ConnectionUtils.class.getClassLoader().getResourceAsStream("tools/db/jdbc/db.properties");
			props.load(is);
			driver = props.getProperty("driver");
			url = props.getProperty("url");
			username = props.getProperty("username");
			password = props.getProperty("password");
			
			Class.forName(driver);

		} catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException("", e);
		}
	}

	/**
	 * 
	 */
	public static Connection openConnection() throws SQLException {
		return DriverManager.getConnection(url, username, password);
	}

方案2：使用hibernate连接oracle为例,在实体中添加表空间的注解
需要在space1的为当前用户授权访问

grant select on 表空间.表名 to 访问用户的表空间;

@Entity
@Table(name = "T_ORDER", schema = "space1")
public class TOrder implements java.io.Serializable {
......
｝

方案3：
使用spring的多数据源切换

<bean name="dataSourceA" class="com.alibaba.druid.pool.DruidDataSource">
</bean>
<bean name="dataSourceB" class="com.alibaba.druid.pool.DruidDataSource">
</bean>
 <bean id="dynamicDataSource" class="ps.frank.moreDB.service.dynamic.DynamicDataSource">  
      <property name="targetDataSources">  
            <map key-type="java.lang.String">  
                <entry value-ref="dataSourceA" key="dataSourceA"></entry>  
                <entry value-ref="dataSourceB" key="dataSourceB"></entry>  
            </map>  
        </property>  
        <property name="defaultTargetDataSource" ref="dataSourceA">  
        </property>  
    </bean>

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

public class DynamicDataSource extends AbstractRoutingDataSource{

	@Override
	protected Object determineCurrentLookupKey() {
		return DBContextHolder.getDBType(); 
	}

}