Spring中基于注解的动态切换数据源方法
主要思路：采用aop方式切入dao方法，为不同dao操作提供不同的数据源配置。
实现方法：
1.AOP类实现注解
a.注解接口
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Datasource {
String value();
}
b.advice
public class DataSourceAdvice implements MethodBeforeAdvice, AfterReturningAdvice, ThrowsAdvice {
private Logger logger = Logger.getLogger(this.getClass());
public void before(Method method, Object[] args, Object target) throws Throwable {
// 方法执行之前，设置数据源
Datasource d = method.getAnnotation(Datasource.class);
String methodName = method.getName();
if(d != null){
String datas = d.value();
if(datas.equals("master")){
DataSourceSwitcher.setMaster();
logger.debug("datasource advice, anotation method:" + methodName + ", database:master.");
}else if(datas.equals("slave")){
DataSourceSwitcher.setSlave();
logger.debug("datasource advice, anotation method:" + methodName + ", database:slave.");
}else if(datas.equals("secondary.master")){
DataSourceSwitcher.setSecondaryMaster();
logger.debug("datasource advice, anotation method:" + methodName + ", database:secondary.master.");
}else if(datas.equals("secondary.slave")){
DataSourceSwitcher.setSecondarySlave();
logger.debug("datasource advice, anotation method:" + methodName + ", database:secondary.slave.");
}
}else if (methodName.startsWith("add")
|| method.getName().startsWith("create")
|| method.getName().startsWith("insert")
|| method.getName().startsWith("save")
|| method.getName().startsWith("edit")
|| method.getName().startsWith("update")
|| method.getName().startsWith("delete")
|| method.getName().startsWith("remove")
|| method.getName().startsWith("replace")) {
DataSourceSwitcher.setMaster();
logger.debug("datasource advice, method:" + methodName + ", database:master.");
} else {
DataSourceSwitcher.setSlave();
logger.debug("datasource advice, method:" + methodName + ", database:slave.");
}
}
public void afterReturning(Object arg0, Method method, Object[] args, Object target) throws Throwable {
}
public void afterThrowing(Method method, Object[] args, Object target, Exception ex) throws Throwable {
DataSourceSwitcher.setSlave();
}
}c.switcher
public class DataSourceSwitcher {
@SuppressWarnings("rawtypes")
private static final ThreadLocal contextHolder = new ThreadLocal();
@SuppressWarnings("unchecked")
public static void setDataSource(String dataSource) {
contextHolder.set(dataSource);
}
public static void setMaster(){
clearDataSource();
}
public static void setSlave() {
setDataSource("slave");
}
public static void setSecondaryMaster() {
setDataSource("secondary.master");
}
public static void setSecondarySlave() {
setDataSource("secondary.slave");
}
public static String getDataSource() {
return (String) contextHolder.get();
}
public static void clearDataSource() {
contextHolder.remove();
}
}d.动态数据源选择类
public class DynamicDataSource extends AbstractRoutingDataSource {
@Override
protected Object determineCurrentLookupKey() {
return DataSourceSwitcher.getDataSource();
}
public Logger getParentLogger() throws SQLFeatureNotSupportedException {
return null;
}
}2.DAO中切入
@Datasource("secondary.master")
int insertOrUpdateTimeLine(List<TimeLine> timeLines);
3.jdbc.properties配置不同数据源
main.master.jdbc.driverClass = com.mysql.jdbc.Driver
main.master.jdbc.jdbcUrl = jdbc:mysql://db.master.url:port/dbname
main.master.jdbc.user = dbuser
main.master.jdbc.password = dbpass
main.slave.jdbc.driverClass = com.mysql.jdbc.Driver
main.slave.jdbc.jdbcUrl = jdbc:mysql://db.slave.url:port/dbname
main.slave.jdbc.user = dbuser
main.slave.jdbc.password = dbpass
secondary.master.jdbc.driverClass = com.mysql.jdbc.Driver
secondary.master.jdbc.jdbcUrl = jdbc:mysql://dbsec.master.url:port/dbname
secondary.master.jdbc.user = dbuser
secondary.master.jdbc.password = dbpass
secondary.slave.jdbc.driverClass = com.mysql.jdbc.Driver
secondary.slave.jdbc.jdbcUrl = jdbc:mysql://dbsec.slave.url:port/dbname
secondary.slave.jdbc.user = dbuser
secondary.slave.jdbc.password = dbpass
jdbc.maxPoolSize = 15
jdbc.minPoolSize = 3
jdbc.initialPoolSize = 3
jdbc.acquireIncrement = 3
jdbc.maxIdleTime = 3600
jdbc.idleConnectionTestPeriod = 604.application.xml中配置数据源选择bean
<!-- 数据库配置begin -->
<bean
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>classpath:/jdbc.properties</value>
</list>
</property>
</bean>
<bean id="parentDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="maxPoolSize" value="${jdbc.maxPoolSize}" />
<property name="minPoolSize" value="${jdbc.minPoolSize}" />
<property name="initialPoolSize" value="${jdbc.initialPoolSize}" />
<property name="acquireIncrement" value="${jdbc.acquireIncrement}" />
<property name="maxIdleTime" value="${jdbc.maxIdleTime}" />
<property name="idleConnectionTestPeriod" value="${jdbc.idleConnectionTestPeriod}" />
</bean>
<!-- main主数据源 -->
<bean id="mainMasterDataSource" parent="parentDataSource">
<property name="driverClass" value="${main.master.jdbc.driverClass}" />
<property name="jdbcUrl" value="${main.master.jdbc.jdbcUrl}" />
<property name="user" value="${main.master.jdbc.user}" />
<property name="password" value="${main.master.jdbc.password}" />
</bean>
<!-- main从数据源 -->
<bean id="mainSlaveDataSource" parent="parentDataSource">
<property name="driverClass" value="${main.slave.jdbc.driverClass}" />
<property name="jdbcUrl" value="${main.slave.jdbc.jdbcUrl}" />
<property name="user" value="${main.slave.jdbc.user}" />
<property name="password" value="${main.slave.jdbc.password}" />
</bean>
<!-- secondary主数据源 -->
<bean id="secondaryMasterDataSource" parent="parentDataSource">
<property name="driverClass" value="${secondary.master.jdbc.driverClass}" />
<property name="jdbcUrl" value="${secondary.master.jdbc.jdbcUrl}" />
<property name="user" value="${secondary.master.jdbc.user}" />
<property name="password" value="${secondary.master.jdbc.password}" />
</bean>
<!-- secondary从数据源 -->
<bean id="secondarySlaveDataSource" parent="parentDataSource">
<property name="driverClass" value="${secondary.slave.jdbc.driverClass}" />
<property name="jdbcUrl" value="${secondary.slave.jdbc.jdbcUrl}" />
<property name="user" value="${secondary.slave.jdbc.user}" />
<property name="password" value="${secondary.slave.jdbc.password}" />
</bean>
<!-- 用于动态选择主、从数据库的数据源实现 -->
<bean id="dataSource" class="com.netease.market3g.aop.DynamicDataSource">
<property name="targetDataSources">
<map key-type="java.lang.String">
<entry key="slave" value-ref="mainSlaveDataSource" />
<entry key="secondary.master" value-ref="secondaryMasterDataSource" />
<entry key="secondary.slave" value-ref="secondarySlaveDataSource" />
</map>
</property>
<property name="defaultTargetDataSource" ref="mainMasterDataSource" />
</bean>转载自：http://blog.sina.com.cn/s/blog_4c7374dd010