Druid动态数据源配置

上文已经讲了单个数据源的Druid的配置（http://www.cnblogs.com/nbfujx/p/7686634.html）

Druid动态数据源配置 主要是继承AbstractRoutingDataSource再通过AOP来实现动态数据源切换

Druid动态数据源的使用（基于原先的程序调整）

使用步骤：

1.调整配置属性文件:mybatis.properties (增加DataSource连接参数)

 master.driver=com.mysql.jdbc.Driver
 master.url=jdbc:mysql://127.0.0.1:3306/jawavesys
 master.username=root
 master.password=jawave88
 #定义初始连接数
 master.initialSize=0
 #定义最大连接数
 master.maxActive=20
 #定义最大空闲
 master.maxIdle=20
 #定义最小空闲
 master.minIdle=1
 #定义最长等待时间
 master.maxWait=60000

 slave.driver=com.mysql.jdbc.Driver
 slave.url=jdbc:mysql://127.0.0.1:3306/jawave_eform
 slave.username=root
 slave.password=jawave88
 #定义初始连接数
 slave.initialSize=0
 #定义最大连接数
 slave.maxActive=20
 #定义最大空闲
 slave.maxIdle=20
 #定义最小空闲
 slave.minIdle=1
 #定义最长等待时间
 slave.maxWait=60000

2.调整SPRING配置文件：spring-base.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:p="http://www.springframework.org/schema/p"
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:tx="http://www.springframework.org/schema/tx"
        xmlns:aop="http://www.springframework.org/schema/aop"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
                         http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                         http://www.springframework.org/schema/context
                         http://www.springframework.org/schema/context/spring-context-3.1.xsd
                         http://www.springframework.org/schema/tx
                         http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
                         http://www.springframework.org/schema/aop
                         http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
                         http://www.springframework.org/schema/mvc
                         http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">

     <context:component-scan base-package="com.goku.druid.demo">
         <context:exclude-filter type="annotation"
                                 expression="org.springframework.stereotype.Controller" />
     </context:component-scan>

     <!-- 引入配置文件 -->
     <bean id="propertyConfigurer"
           class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
         <property name="location" value="classpath:mybatis.properties" />
     </bean>

     <bean id="masterDataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
         <property name="driverClassName" value="${master.driver}" />
         <property name="url" value="${master.url}" />
         <property name="username" value="${master.username}" />
         <property name="password" value="${master.password}" />
         <!-- 初始化连接大小 -->
         <property name="initialSize" value="${master.initialSize}"></property>
         <!-- 连接池最大数量 -->
         <property name="maxActive" value="${master.maxActive}"></property>
         <!-- 连接池最大空闲 -->
         <property name="maxIdle" value="${master.maxIdle}"></property>
         <!-- 连接池最小空闲 -->
         <property name="minIdle" value="${master.minIdle}"></property>
         <!-- 获取连接最大等待时间 -->
         <property name="maxWait" value="${master.maxWait}"></property>
         <!-- 这里配置提交方式，默认就是TRUE，可以不用配置 -->
         <property name="defaultAutoCommit" value="true" />
         <!-- 验证连接有效与否的SQL，不同的数据配置不同 -->
         <property name="validationQuery" value="select 1 " />
         <!--通过别名的方式配置扩展插件,监控统计用的filter:stat  日志用的filter:log4j  防御sql注入的filter:wall-->
         <property name="filters" value="stat,log4j" />
         <property name="proxyFilters">
             <list>
                 <ref bean="stat-filter" />
                 <ref bean="log-filter"/>
             </list>
         </property>
     </bean>

     <bean id="slaveDataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
         <property name="driverClassName" value="${slave.driver}" />
         <property name="url" value="${slave.url}" />
         <property name="username" value="${slave.username}" />
         <property name="password" value="${slave.password}" />
         <!-- 初始化连接大小 -->
         <property name="initialSize" value="${slave.initialSize}"></property>
         <!-- 连接池最大数量 -->
         <property name="maxActive" value="${slave.maxActive}"></property>
         <!-- 连接池最大空闲 -->
         <property name="maxIdle" value="${slave.maxIdle}"></property>
         <!-- 连接池最小空闲 -->
         <property name="minIdle" value="${slave.minIdle}"></property>
         <!-- 获取连接最大等待时间 -->
         <property name="maxWait" value="${slave.maxWait}"></property>
         <!-- 这里配置提交方式，默认就是TRUE，可以不用配置 -->
         <property name="defaultAutoCommit" value="true" />
         <!-- 验证连接有效与否的SQL，不同的数据配置不同 -->
         <property name="validationQuery" value="select 1 " />
         <!--通过别名的方式配置扩展插件,监控统计用的filter:stat  日志用的filter:log4j  防御sql注入的filter:wall-->
         <property name="filters" value="stat,log4j" />
         <property name="proxyFilters">
             <list>
                 <ref bean="stat-filter" />
                 <ref bean="log-filter"/>
             </list>
         </property>
     </bean>

     <bean id="dataSource" class="com.goku.druid.demo.util.DynamicDataSource">
         <property name="targetDataSources">
             <map key-type="java.lang.String">
                 <!-- master -->
                 <entry key="master" value-ref="masterDataSource"/>
                 <!-- slave -->
                 <entry key="slave" value-ref="slaveDataSource"/>
             </map>
         </property>
         <property name="defaultTargetDataSource" ref="masterDataSource"/>
     </bean>

     <!-- spring和MyBatis完美整合，不需要mybatis的配置映射文件 -->
     <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
         <property name="dataSource" ref="dataSource" />
         <!-- 自动扫描mapping.xml文件 -->
         <property name="mapperLocations" value="classpath:mapping/**/*.xml"></property>
     </bean>

     <!-- DAO接口所在包名，Spring会自动查找其下的类 -->
     <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
         <property name="basePackage" value="com.goku.druid.demo.mapper" />
         <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
     </bean>

     <!-- (事务管理)transaction manager, use JtaTransactionManager for global tx -->
     <bean id="transactionManager"
           class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
         <property name="dataSource" ref="dataSource" />
     </bean>

     <!-- 开启事务注解驱动 -->
     <tx:annotation-driven  transaction-manager="transactionManager"/>

     <!-- 为业务逻辑层的方法解析@DataSource注解  为当前线程的routeholder注入数据源key -->
     <bean id="dataSourceAspect" class="com.goku.druid.demo.util.DataSourceAspect" />
     <aop:config proxy-target-class="true">
         <aop:aspect id="dataSourceAspect" ref="dataSourceAspect" order="1">
             <aop:pointcut id="tx" expression="execution(* com.goku.druid.demo.service..*.*(..)) "/>
             <aop:before pointcut-ref="tx" method="before" />
         </aop:aspect>
     </aop:config>

     <!--监控统计-->
     <bean id="stat-filter" class="com.alibaba.druid.filter.stat.StatFilter">
         <property name="slowSqlMillis" value="10000" />
         <property name="logSlowSql" value="true" />
     </bean>

     <!--日志-->
     <bean id="log-filter" class="com.alibaba.druid.filter.logging.Log4jFilter">
         <property name="statementExecutableSqlLogEnable" value="true" />
     </bean>

 </beans>

3.接下写AbstractRoutingDataSource继承类

package com.goku.druid.demo.util;

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

/**
 * Created by nbfujx on 2017/10/18.
 */
public class DynamicDataSource extends AbstractRoutingDataSource  {

    @Override
    protected Object determineCurrentLookupKey() {
        return DataSourceHolder.getDataSource();
    }

}

4.接下来写切面实现类

package com.goku.druid.demo.util;

import java.lang.reflect.Method;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.reflect.MethodSignature;

/**
 *  Created by nbfujx on 2017/10/18.
 */
public class DataSourceAspect {

    /**
     * 在dao层方法之前获取datasource对象之前在切面中获取数据源
     */
    public void before(JoinPoint point)
    {
        Object target = point.getTarget();
        System.out.println(target.toString());
        String method = point.getSignature().getName();
        System.out.println(method);
        Class<?>[] classz = target.getClass().getInterfaces();
        Class<?>[] parameterTypes = ((MethodSignature) point.getSignature())
                .getMethod().getParameterTypes();
        try {
            Method m = classz[0].getMethod(method, parameterTypes);
            System.out.println("method"+ m.getName());
            if (m != null && m.isAnnotationPresent(DataSource.class)) {
                DataSource data = m.getAnnotation(DataSource.class);
                System.out.println("dataSource："+data.value());
                DataSourceHolder.putDataSource(data.value());
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

5.还有拿到数据元的类

package com.goku.druid.demo.util;

/**
 * Created by nbfujx on 2017/10/18.
 */
public class DataSourceHolder {
    public static final ThreadLocal<String> holder = new ThreadLocal<String>();

    /**
     * 设置数据源
     */
    public static void putDataSource(String datasource) {
        holder.set(datasource);
    }

    /**
     * 获取数据源
     */
    public static String getDataSource() {
        return holder.get();
    }

    /**
     * 清除数据源
     */
    public static void clearDataSource() {
        holder.remove();
    }
}

6.DataSource数据源注解类

package com.goku.druid.demo.util;

import java.lang.annotation.ElementType;
import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

/**
 * Created by nbfujx on 2017/10/18.
 */

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface DataSource {
    String value();
}

7.在service层进行数据源注解切换

package com.goku.druid.demo.service;

import com.goku.druid.demo.model.FormElement;
import com.goku.druid.demo.model.UserWithBLOBs;
import com.goku.druid.demo.util.DataSource;

/**
 * Created by nbfujx on 2017-10-18.
 */
public interface UserService {
    @DataSource("master")
    UserWithBLOBs selectByPrimaryKey(String id);

    @DataSource("slave")
    FormElement selectByPrimaryKey2(Integer id);
}

GITHUB

github :  https://github.com/nbfujx/learn-java-demo/tree/master/Goku.Dynamic.DruidDemo