#主數(shù)據(jù)源
druid.master.url=jdbc:mysql://url/masterdb?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull
druid.master.username=xxx
druid.master.password=123
druid.master.driver-class-name=com.mysql.jdbc.Driver
druid.master.max-wait=5000
druid.master.max-active=100
druid.master.test-on-borrow=true
druid.master.validation-query=SELECT 1

#從數(shù)據(jù)源
druid.slave.url=jdbc:mysql://url/slavedb?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull
druid.slave.username=xxx
druid.slave.password=123
druid.slave.driver-class-name=com.mysql.jdbc.Driver
druid.slave.max-wait=5000
druid.slave.max-active=100
druid.slave.test-on-borrow=true
druid.slave.validation-query=SELECT 1

<!-- master數(shù)據(jù)源 -->
<bean primary="true" id="masterdb" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
  <!-- 基本屬性 url、user、password -->
  <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
  <property name="url" value="${druid.master.url}"/>
  <property name="username" value="${druid.master.username}"/>
  <property name="password" value="${druid.master.password}"/>
  <!-- 配置初始化最大 -->
  <property name="maxActive" value="${druid.master.max-active}"/>
  <!-- 配置獲取連接等待超時(shí)的時(shí)間 -->
  <property name="maxWait" value="${druid.master.max-wait}"/>
  <property name="validationQuery" value="${druid.master.validation-query}"/>
  <property name="testOnBorrow" value="${druid.master.test-on-borrow}"/>

</bean>

<!-- slave數(shù)據(jù)源 -->
<bean primary="true" id="slavedb" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
  <!-- 基本屬性 url、user、password -->
  <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
  <property name="url" value="${druid.slave.url}"/>
  <property name="username" value="${druid.slave.username}"/>
  <property name="password" value="${druid.slave.password}"/>

  <!-- 配置初始化大小、最小、最大 -->
  <property name="maxActive" value="${druid.slave.max-active}"/>
  <!-- 配置獲取連接等待超時(shí)的時(shí)間 -->
  <property name="maxWait" value="${druid.slave.max-wait}"/>
  <property name="validationQuery" value="${druid.slave.validation-query}"/>
  <property name="testOnBorrow" value="${druid.slave.test-on-borrow}"/>
</bean>

<!-- 動(dòng)態(tài)數(shù)據(jù)源，根據(jù)service接口上的注解來決定取哪個(gè)數(shù)據(jù)源 -->
<bean id="dataSource" class="datasource.DynamicDataSource">
  <property name="targetDataSources">
    <map key-type="java.lang.String">
      <entry key="slave" value-ref="slavedb"/>
      <entry key="master" value-ref="masterdb"/>
    </map>
  </property>
  <property name="defaultTargetDataSource" ref="masterdb"/>
</bean>

<!-- Spring JdbcTemplate -->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
  <property name="dataSource" ref="dataSource" />
</bean>

<!-- Spring事務(wù)管理器 -->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
  <property name="dataSource" ref="dataSource" />
</bean>

<bean id="transactionTemplate" class="org.springframework.transaction.support.TransactionTemplate">
  <property name="transactionManager" ref="transactionManager"/>
</bean>

<tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="true" order="2" />

<!-- depositdbSqlSessionFactory -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
  <property name="dataSource" ref="dataSource" />
  <property name="mapperLocations" value="classpath*:mapper-xxdb/*Mapper*.xml" />
</bean>

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
  <property name="basePackage" value="xxdb.mapper"/>
  <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
</bean>

public class DynamicDataSource extends AbstractRoutingDataSource {
  private Logger logger = LoggerFactory.getLogger(this.getClass());

  @Override
  protected Object determineCurrentLookupKey() {
    String dataSource = JdbcContextHolder.getDataSource();
    logger.info("數(shù)據(jù)源為{}",dataSource);
    return dataSource;
  }
}

@Aspect
@Order(1)  //設(shè)置AOP執(zhí)行順序(需要在事務(wù)之前，否則事務(wù)只發(fā)生在默認(rèn)庫中)
@Component
public class DataSourceAspect {

  private Logger logger = LoggerFactory.getLogger(this.getClass());
  //切點(diǎn)
  @Pointcut("execution(* com.xxx.service.*.*(..))")
  public void aspect() { }

  @Before("aspect()")
  private void before(JoinPoint point) {
    Object target = point.getTarget();
    String method = point.getSignature().getName();
    Class<?> classz = target.getClass();// 獲取目標(biāo)類
    Class<?>[] parameterTypes = ((MethodSignature) point.getSignature())
        .getMethod().getParameterTypes();
    try {
      Method m = classz.getMethod(method, parameterTypes);
      if (m != null && m.isAnnotationPresent(MyDataSource.class)) {
        MyDataSource data = m.getAnnotation(MyDataSource.class);
        logger.info("method :{},datasource:{}",m.getName() ,data.value().getName());
        JdbcContextHolder.putDataSource(data.value().getName());// 數(shù)據(jù)源放到當(dāng)前線程中
      }
    } catch (Exception e) {
      logger.error("get datasource error ",e);
      //默認(rèn)選擇master
      JdbcContextHolder.putDataSource(DataSourceType.Master.getName());// 數(shù)據(jù)源放到當(dāng)前線程中
    }

  }

  @AfterReturning("aspect()")
  public void after(JoinPoint point) {
    JdbcContextHolder.clearDataSource();
  }
}

public class JdbcContextHolder {

  private final static ThreadLocal<String> local = new ThreadLocal<>();

  public static void putDataSource(String name) {
    local.set(name);
  }

  public static String getDataSource() {
    return local.get();
  }

  public static void clearDataSource() {
    local.remove();
  }
}

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface MyDataSource {

  DataSourceType value();

}
public enum DataSourceType {
  // 主表
  Master("master"),
  // 從表
  Slave("slave");

  private String name;

  private DataSourceType(String name) {
    this.name = name;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }
}

@Component
public class xxxServiceImpl {
  @Resource
  private XxxMapperExt xxxMapperExt;

  @MyDataSource(value= DataSourceType.Slave)
  public List<Object> getAll(){
    return xxxMapperExt.getAll();
  }
}