spring-spring mvc-mybatis 实现主从数据库配置

一、配置文件

1、spring-mybatis.xml

master_driverUrl=jdbc:mysql://localhost:3306/shiro?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&transformedBitIsBoolean=truemaster_username=rootmaster_password=12345slave_driverUrl=jdbc:mysql://localhost:3306/wechat?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&transformedBitIsBoolean=trueslave_username=rootslave_password=12345

2、spring-mybatis.xml

<!-- 多数据源aop datasource -->    <context:component-scan base-package="com.wangzhixuan.commons.datasource" />    <!-- base dataSource -->    <bean name="baseDataSource" class="com.alibaba.druid.pool.DruidDataSource"        destroy-method="close">        <property name="initialSize" value="5" />        <property name="maxActive" value="100" />        <property name="minIdle" value="10" />        <property name="maxWait" value="60000" />        <property name="validationQuery" value="SELECT 'x'" />        <property name="testOnBorrow" value="true" />        <property name="testOnReturn" value="true" />        <property name="testWhileIdle" value="true" />        <property name="timeBetweenEvictionRunsMillis" value="60000" />        <property name="minEvictableIdleTimeMillis" value="300000" />        <property name="removeAbandoned" value="true" />        <property name="removeAbandonedTimeout" value="1800" />        <property name="logAbandoned" value="true" />        <property name="filters" value="mergeStat" />    </bean>    <!-- 主库 -->    <bean name="master-dataSource" parent="baseDataSource"        init-method="init">        <property name="url" value="${master_driverUrl}" />        <property name="username" value="${master_username}" />        <property name="password" value="${master_password}" />    </bean>    <!-- 从库 -->    <bean name="slave-dataSource" parent="baseDataSource" init-method="init">        <property name="url" value="${slave_driverUrl}" />        <property name="username" value="${slave_username}" />        <property name="password" value="${slave_password}" />    </bean>        <!--主从库选择 -->    <bean id="dynamicDataSource" class="com.wangzhixuan.commons.datasource.DynamicDataSource">        <property name="master" ref="master-dataSource" />        <property name="slaves">            <list>                <ref bean="slave-dataSource" />            </list>        </property>    </bean>

二、通用类

package com.wangzhixuan.commons.datasource;import com.wangzhixuan.commons.annotation.DataSourceChange;import com.wangzhixuan.commons.exception.DataSourceAspectException;import org.aspectj.lang.ProceedingJoinPoint;import org.aspectj.lang.annotation.Around;import org.aspectj.lang.annotation.Aspect;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.stereotype.Component;/** * 有{@link com.wangzhixuan.commons.annotation.DataSourceChange}注解的方法，调用时会切换到指定的数据源 * * @author tanghd */@Aspect@Componentpublic class DataSourceAspect {    private static final Logger LOGGER = LoggerFactory.getLogger(DataSourceAspect.class);    @Around("@annotation(dataSourceChange)")    public Object doAround(ProceedingJoinPoint pjp, DataSourceChange dataSourceChange) {        Object retVal = null;        boolean selectedDataSource = false;        try {            if (null != dataSourceChange) {                selectedDataSource = true;                if (dataSourceChange.slave()) {                    DynamicDataSource.useSlave();                } else {                    DynamicDataSource.useMaster();                }            }            retVal = pjp.proceed();        } catch (Throwable e) {            LOGGER.warn("数据源切换错误", e);            throw new DataSourceAspectException("数据源切换错误", e);        } finally {            if (selectedDataSource) {                DynamicDataSource.reset();            }        }        return retVal;    }}

package com.wangzhixuan.commons.datasource;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;import javax.sql.DataSource;import java.util.HashMap;import java.util.LinkedList;import java.util.List;import java.util.Map;import java.util.concurrent.atomic.AtomicLong;/** * 继承{@link org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource} * 配置主从数据源后，根据选择，返回对应的数据源。多个从库的情况下，会平均的分配从库，用于负载均衡。 * * @author tanghd */public class DynamicDataSource extends AbstractRoutingDataSource {    private static final Logger LOGGER = LoggerFactory.getLogger(DynamicDataSource.class);    private DataSource master; // 主库，只允许有一个    private List<DataSource> slaves; // 从库，允许有多个    private AtomicLong slaveCount = new AtomicLong();    private int slaveSize = 0;    private Map<Object, Object> dataSources = new HashMap<Object, Object>();    private static final String DEFAULT = "master";    private static final String SLAVE = "slave";    private static final ThreadLocal<LinkedList<String>> datasourceHolder = new ThreadLocal<LinkedList<String>>() {        @Override        protected LinkedList<String> initialValue() {            return new LinkedList<String>();        }    };    /**     * 初始化     */    @Override    public void afterPropertiesSet() {        if (null == master) {            throw new IllegalArgumentException("Property 'master' is required");        }        dataSources.put(DEFAULT, master);        if (null != slaves && slaves.size() > 0) {            for (int i = 0; i < slaves.size(); i++) {                dataSources.put(SLAVE + (i + 1), slaves.get(i));            }            slaveSize = slaves.size();        }        this.setDefaultTargetDataSource(master);        this.setTargetDataSources(dataSources);        super.afterPropertiesSet();    }    /**     * 选择使用主库，并把选择放到当前ThreadLocal的栈顶     */    public static void useMaster() {        if (LOGGER.isDebugEnabled()) {            LOGGER.debug("use datasource :" + datasourceHolder.get());        }        LinkedList<String> m = datasourceHolder.get();        m.offerFirst(DEFAULT);    }    /**     * 选择使用从库，并把选择放到当前ThreadLocal的栈顶     */    public static void useSlave() {        if (LOGGER.isDebugEnabled()) {            LOGGER.debug("use datasource :" + datasourceHolder.get());        }        LinkedList<String> m = datasourceHolder.get();        m.offerFirst(SLAVE);    }    /**     * 重置当前栈     */    public static void reset() {        LinkedList<String> m = datasourceHolder.get();        if (LOGGER.isDebugEnabled()) {            LOGGER.debug("reset datasource {}", m);        }        if (m.size() > 0) {            m.poll();        }    }    /**     * 如果是选择使用从库，且从库的数量大于1，则通过取模来控制从库的负载,     * 计算结果返回AbstractRoutingDataSource     */    @Override    protected Object determineCurrentLookupKey() {        LinkedList<String> m = datasourceHolder.get();        String key = m.peekFirst() == null ? DEFAULT : m.peekFirst();        if (LOGGER.isDebugEnabled()) {            LOGGER.debug("currenty datasource :" + key);        }        if (null != key) {            if (DEFAULT.equals(key)) {                return key;            } else if (SLAVE.equals(key)) {                if (slaveSize > 1) {// Slave loadBalance                    long c = slaveCount.incrementAndGet();                    c = c % slaveSize;                    return SLAVE + (c + 1);                } else {                    return SLAVE + "1";                }            }            return null;        } else {            return null;        }    }    public DataSource getMaster() {        return master;    }    public List<DataSource> getSlaves() {        return slaves;    }    public void setMaster(DataSource master) {        this.master = master;    }    public void setSlaves(List<DataSource> slaves) {        this.slaves = slaves;    }}

package com.wangzhixuan.commons.annotation;import java.lang.annotation.ElementType;import java.lang.annotation.Inherited;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;@Inherited@Target(ElementType.METHOD)@Retention(RetentionPolicy.RUNTIME)public @interface DataSourceChange {    boolean slave() default false;}

三、在服务层调用时加入数据源标识，DataSourceChange注解，设置数据源为从库（这里只写出了接口的实现，dao和mapper，请自行添加）

package com.wangzhixuan.service.impl;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import com.wangzhixuan.commons.annotation.DataSourceChange;import com.wangzhixuan.mapper.SlaveMapper;import com.wangzhixuan.service.SlaveService;@Servicepublic class SlaveServiceImpl implements SlaveService {    @Autowired    private SlaveMapper slaveMapper;    @Override    @DataSourceChange(slave = true)    public Integer count() {        return slaveMapper.count();    }    @Override    @DataSourceChange(slave = true)    public Integer count2() {        return slaveMapper.count2();    }}

四、测试类（这里是查询从库里的一张表的记录总数），将原来的主库切换到从库。

   @Test    public void testFindAllShop() {        Integer count = slaveService.count();        //Integer count2 = slaveService.count2();        System.out.println("#######1:"+count);    }