Spring 動態資料來源和AOP實現資料庫讀寫分離
阿新 • • 發佈:2019-01-31
網際網路架構演進中 資料庫優化是不可或缺的一環,資料庫層面優化分為兩個階段:讀寫分離、分庫分表。
今天要說的是 資料庫讀寫分離技術,其原理就是一個Master資料庫,多個Slave資料庫。Master庫負責資料更新和實時資料查詢,Slave庫當然負責非實時資料查詢。因為在實際的應用中,資料庫都是讀多寫少(讀取資料的頻率高,更新資料的頻率相對較少),而讀取資料通常耗時比較長,佔用資料庫伺服器的CPU較多,從而影響使用者體驗。
我們通常的做法就是把查詢從主庫中抽取出來,分發到多個從庫上,減輕主庫的壓力。
採用讀寫分離技術的目標:有效減輕Master庫的壓力,又可以把使用者查詢資料的請求分發到不同的Slave庫,從而保證系統的健壯性。
實現原理
在DAO實現類的方法加上@RoutingDataSource註解,然後通過Spring AOP技術在執行時攔截DAO的方法,獲取方法上的@RoutingDataSource註解值動態切換資料來源。
程式碼實現
1、Spring動態資料來源
1、spring-dao.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd"
default-lazy-init="false">
<bean id="parentDataSource" class="com.alibaba.druid.pool.DruidDataSource"
destroy-method="close" abstract="true" init-method="init" >
<!-- 初始化連線大小 -->
<property name="initialSize" value="2" />
<!-- 連線池最大使用連線數量 -->
<property name="maxActive" value="10" />
<!-- 連線池最小空閒 -->
<property name="minIdle" value="5" />
<!-- 獲取連線最大等待時間 -->
<property name="maxWait" value="30000" />
<!-- <property name="poolPreparedStatements" value="true" /> -->
<!-- <property name="maxPoolPreparedStatementPerConnectionSize" value="33" /> -->
<property name="validationQuery" value="SELECT 1" />
<property name="testOnBorrow" value="false" />
<property name="testOnReturn" value="false" />
<property name="testWhileIdle" value="true" />
<!-- 配置間隔多久才進行一次檢測,檢測需要關閉的空閒連線,單位是毫秒 -->
<property name="timeBetweenEvictionRunsMillis" value="60000" />
<!-- 配置一個連線在池中最小生存的時間,單位是毫秒 -->
<property name="minEvictableIdleTimeMillis" value="25200000" />
<!-- 開啟removeAbandoned功能 -->
<property name="removeAbandoned" value="true" />
<!-- 1800秒,也就是30分鐘 -->
<property name="removeAbandonedTimeout" value="1800" />
<!-- 關閉abanded連線時輸出錯誤日誌 -->
<property name="logAbandoned" value="true" />
<!-- 監控資料庫 -->
<!-- <property name="filters" value="stat" /> -->
<property name="filters" value="mergeStat" />
</bean>
<!-- 配置資料來源-->
<bean id="masterDataSource" parent="parentDataSource">
<property name="url" value="#{jdbc['master.jdbc.url']}" />
<property name="username" value="#{jdbc['master.jdbc.username']}" />
<property name="password" value="#{jdbc['master.jdbc.password']}" />
<property name="driverClassName" value="#{jdbc['master.jdbc.driver']}" />
<property name="maxActive" value="15" />
</bean>
<bean id="slaveDataSource" parent="parentDataSource">
<property name="url" value="#{jdbc['slave1.jdbc.url']}" />
<property name="username" value="#{jdbc['slave1.jdbc.username']}" />
<property name="password" value="#{jdbc['slave1.jdbc.password']}" />
<property name="driverClassName" value="#{jdbc['slave1.jdbc.driver']}" />
</bean>
<!--動態資料來源-->
<bean id="dataSource" class="com.bytebeats.spring4.sample.ds.DynamicRoutingDataSource">
<property name="targetDataSources">
<map key-type="com.bytebeats.spring4.sample.ds.RoutingStrategy">
<entry key="WRITE" value-ref="masterDataSource"/>
<entry key="READ" value-ref="slaveDataSource"/>
</map>
</property>
<!-- 預設目標資料來源為主庫資料來源 -->
<property name="defaultTargetDataSource" ref="masterDataSource"/>
</bean>
<!--Spring JdbcTemplate-->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"/>
</bean>
<!-- 註解方式配置事物 -->
<tx:annotation-driven transaction-manager="transactionManager" />
<!-- 配置事務管理器 -->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="masterDataSource" />
</bean>
</beans>
2、動態資料來源實現
DynamicRoutingDataSource.java
package com.bytebeats.spring4.sample.ds;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
/**
* 動態資料來源
*
* @author Ricky Fung
* @create 2016-12-30 11:12
*/
public class DynamicRoutingDataSource extends AbstractRoutingDataSource {
@Override
protected Object determineCurrentLookupKey() {
return DynamicRoutingContextHolder.getRouteStrategy();
}
}
DynamicRoutingContextHolder.java
package com.bytebeats.spring4.sample.ds;
import org.springframework.util.Assert;
/**
* ${DESCRIPTION}
*
* @author Ricky Fung
* @create 2016-12-30 11:14
*/
public class DynamicRoutingContextHolder {
private static final ThreadLocal<RoutingStrategy> contextHolder =
new ThreadLocal<>();
public static void setRouteStrategy(RoutingStrategy customerType) {
Assert.notNull(customerType, "customerType cannot be null");
contextHolder.set(customerType);
}
public static RoutingStrategy getRouteStrategy() {
return (RoutingStrategy) contextHolder.get();
}
public static void clearRouteStrategy() {
contextHolder.remove();
}
}
RoutingStrategy.java
package com.bytebeats.spring4.sample.ds;
/**
* 讀寫策略
*
* @author Ricky Fung
* @create 2016-12-30 11:14
*/
public enum RoutingStrategy {
WRITE, READ;
}
資料來源註解
package com.bytebeats.spring4.sample.annotation;
import com.bytebeats.spring4.sample.ds.RoutingStrategy;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* ${DESCRIPTION}
*
* @author Ricky Fung
* @date 2016-12-30 15:26
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface RoutingDataSource {
RoutingStrategy value();
}
Spring AOP
1、spring-aop.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
<!-- 配置AOP -->
<aop:aspectj-autoproxy />
<bean id="readWriteSeparateAspect" class="com.bytebeats.spring4.sample.aop.DBReadWriteSeparateAspect" />
<aop:config>
<aop:aspect ref="readWriteSeparateAspect">
<aop:pointcut id="rw" expression="execution(* com.bytebeats.spring4.sample.dao.*.*(..))" />
<aop:before pointcut-ref="rw" method="before" />
</aop:aspect>
</aop:config>
</beans>
2、切面類
package com.bytebeats.spring4.sample.aop;
import com.bytebeats.spring4.sample.annotation.RoutingDataSource;
import com.bytebeats.spring4.sample.ds.DynamicRoutingContextHolder;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.lang.reflect.Method;
/**
* ${DESCRIPTION}
*
* @author Ricky Fung
* @date 2016-12-30 16:59
*/
public class DBReadWriteSeparateAspect {
private final Logger logger = LoggerFactory.getLogger(getClass());
public void before(JoinPoint point) {
Object target = point.getTarget();
String methodName = point.getSignature().getName();
Class<?> clazz = target.getClass();
logger.info("before class:{} method:{} execute", clazz.getName(), methodName);
Class<?>[] parameterTypes = ((MethodSignature) point.getSignature()).getMethod().getParameterTypes();
try {
Method method = clazz.getMethod(methodName, parameterTypes);
if (method != null && method.isAnnotationPresent(RoutingDataSource.class)) {
RoutingDataSource data = method.getAnnotation(RoutingDataSource.class);
DynamicRoutingContextHolder.setRouteStrategy(data.value());
logger.info("class:{} method:{} 切換資料來源:{} 成功", clazz.getName(), methodName, data.value());
}
} catch (Exception e) {
logger.error("資料來源切換切面異常", e);
}
}
}
如何使用
假設有一個訂單庫,現在要實現訂單表的插入和查詢,IOrderDao介面定義如下:
package com.bytebeats.spring4.sample.dao;
import com.bytebeats.spring4.sample.domain.Order;
import java.util.List;
/**
* ${DESCRIPTION}
*
* @author Ricky Fung
* @create 2016-12-30 11:15
*/
public interface IOrderDao {
long insert(Order order);
List<Order> queryOrders();
}
我們期望insert路由到主庫上,queryOrders路由到從庫上,那麼我們只需要在這兩個方法上增加@RoutingDataSource註解即可,OrderDaoImpl 程式碼如下:
package com.bytebeats.spring4.sample.dao.impl;
import com.bytebeats.spring4.sample.annotation.RoutingDataSource;
import com.bytebeats.spring4.sample.dao.IOrderDao;
import com.bytebeats.spring4.sample.domain.Order;
import com.bytebeats.spring4.sample.ds.RoutingStrategy;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;
import javax.annotation.Resource;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
/**
* ${DESCRIPTION}
*
* @author Ricky Fung
* @create 2016-12-30 11:16
*/
@Repository("orderDao")
public class OrderDaoImpl implements IOrderDao {
@Resource(name = "jdbcTemplate")
private JdbcTemplate jdbcTemplate;
@RoutingDataSource(RoutingStrategy.WRITE)
@Override
public long insert(Order order) {
String sql = "INSERT INTO tb_order(customer_name,total_price,amount,address) VALUES (?,?,?,?)";
return jdbcTemplate.update(sql, order.getCustomerName(),
order.getTotalPrice(), order.getAmount(), order.getAddress());
}
@RoutingDataSource(RoutingStrategy.READ)
@Override
public List<Order> queryOrders(){
return jdbcTemplate.query("SELECT * FROM tb_order", new RowMapper<Order>() {
@Override
public Order mapRow(ResultSet rs, int i) throws SQLException {
Order order = new Order();
order.setId(rs.getLong("id"));
order.setCustomerName(rs.getString("customer_name"));
order.setTotalPrice(rs.getDouble("total_price"));
order.setAmount(rs.getInt("amount"));
order.setAddress(rs.getString("address"));
return order;
}
});
}
}