数维图SSM框架后端技术帖：多个数据源的配置

jdbc.user=root
jdbc.password=root
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssm_base?characterEncoding=utf8
 
jdbc.r1.user=root
jdbc.r1.password=root
jdbc.r1.driver=com.mysql.jdbc.Driver
jdbc.r1.url=jdbc:mysql://localhost:3306/etravel?characterEncoding=utf8

<context:property-placeholder location="classpath:applicationContext-jdbc.properties"/>
     
    <!-- 配置数据库连接池 c3p0   -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
       <!-- 配置链接数据库的基本属性 -->
        <property name="user" value="${jdbc.user}" />
        <property name="password" value="${jdbc.password}" />
        <property name="jdbcUrl" value="${jdbc.url}" />
        <property name="driverClass" value="${jdbc.driver}" />
        <!-- 配置 c3p0 的数据源自身的属性 -->
        <property name="minPoolSize" value="${jdbc.minPoolSize}" />
        <property name="initialPoolSize" value="${jdbc.initialPoolSize}" />
        <property name="maxPoolSize" value="${jdbc.maxPoolSize}" />
        <property name="acquireIncrement" value="${jdbc.acquireIncrement}" />
        <property name="maxIdleTime" value="${jdbc.maxIdleTime}"></property>
        <property name="acquireRetryAttempts" value="${jdbc.acquireRetryAttempts}" />
        <property name="autoCommitOnClose" value="${jdbc.autoCommitOnClose}" />
        <property name="breakAfterAcquireFailure" value="${jdbc.breakAfterAcquireFailure}" />
        <property name="checkoutTimeout" value="${jdbc.checkoutTimeout}" />
        <property name="maxStatements" value="${jdbc.maxStatements}"></property>
        <property name="maxStatementsPerConnection" value="${jdbc.maxStatementsPerConnection}"></property>
        <property name="numHelperThreads" value="${jdbc.numHelperThreads}"></property>
       <property name="idleConnectionTestPeriod" value="${jdbc.idleConnectionTestPeriod}"></property>
     </bean>
    <!--  -->
    <bean id="dataSourceR1" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="user" value="${jdbc.r1.user}" />
        <property name="password" value="${jdbc.r1.password}" />
        <property name="jdbcUrl" value="${jdbc.r1.url}" />
        <property name="driverClass" value="${jdbc.r1.driver}" />
        <property name="minPoolSize" value="${jdbc.minPoolSize}" />
        <property name="initialPoolSize" value="${jdbc.initialPoolSize}" />
        <property name="maxPoolSize" value="${jdbc.maxPoolSize}" />
        <property name="acquireIncrement" value="${jdbc.acquireIncrement}" />
        <property name="maxIdleTime" value="${jdbc.maxIdleTime}"></property>
        <property name="acquireRetryAttempts" value="${jdbc.acquireRetryAttempts}" />
        <property name="autoCommitOnClose" value="${jdbc.autoCommitOnClose}" />
        <property name="breakAfterAcquireFailure" value="${jdbc.breakAfterAcquireFailure}" />
        <property name="checkoutTimeout" value="${jdbc.checkoutTimeout}" />
        <property name="maxStatements" value="${jdbc.maxStatements}"></property>
        <property name="maxStatementsPerConnection" value="${jdbc.maxStatementsPerConnection}"></property>
        <property name="numHelperThreads" value="${jdbc.numHelperThreads}"></property>
       <property name="idleConnectionTestPeriod" value="${jdbc.idleConnectionTestPeriod}"></property>
     </bean>

package com.sovitjs.manager.base;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
/**
 * @author 
 *
 */
public class DBContextHolder {
     
    /*
     * 程threadlocal 
    */  
    private static ThreadLocal<String> contextHolder = new ThreadLocal<String>(); 
     
    public static String DB_TYPE_W = "dataSourceKey";
    public static String DB_TYPE_R1 = "dataSourceKeyR1";
     
    public static boolean DB_TYPE_W_VALID = true;
    public static boolean DB_TYPE_R1_VALID = false;
     
    public static final Map<String,String> mysqlIpMap = new HashMap<String,String>(){{
        put(DB_TYPE_W,"192.168.1.109");
        //put(DB_TYPE_R1,"192.168.1.108");
    }};
     
    public static String getDbType() {
        String db = contextHolder.get();
        if(db == null) {
            db = DB_TYPE_W;
        }
        return db;
    }
     
    public static void setDbType(String str) {  
        contextHolder.set(str);  
    }
     
    public static void setDbType(int wrType) {
        if(wrType == 1) {
            contextHolder.set(DBContextHolder.DB_TYPE_W);
        }else if(wrType == 2) {
            Map<String,String> rMap = new HashMap<String,String>();
            System.out.println("-------------------DB_TYPE_R1_VALID:"+DB_TYPE_R1_VALID);
            List<String> idList = new ArrayList<String>();
            if(DB_TYPE_R1_VALID == true) {
                rMap.put("1", DBContextHolder.DB_TYPE_R1);
                idList.add("1");
            }
            System.out.println("-------------------DB_TYPE_W_VALID:"+DB_TYPE_W_VALID);
            if(DB_TYPE_W_VALID == true) {
                rMap.put("2", DBContextHolder.DB_TYPE_W);
                idList.add("2");
            }
            String[] ids = (String[])idList.toArray(new String[0]);
            Random rnd = new Random();
            Integer startNum = rnd.nextInt(ids.length);
            String theId = ids[startNum];
            System.out.println("-------------------rMap.get(theId):"+rMap.get(theId));
            contextHolder.set(rMap.get(theId));
        }
    }
     
    public static void clearDBType() {
        contextHolder.remove();
    }
}

import java.sql.SQLFeatureNotSupportedException;
import java.util.logging.Logger;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
/**
 * @author c
 *
 */
public class DynamicDataSource extends AbstractRoutingDataSource {
    /* (non-Javadoc)
     * @see org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource#determineCurrentLookupKey()
     */
    @Override
    protected Object determineCurrentLookupKey() {
        // TODO Auto-generated method stub
         return DBContextHolder.getDbType();
    }
    @Override
    public Logger getParentLogger() throws SQLFeatureNotSupportedException {
        // TODO Auto-generated method stub
        return null;
    }
}

<!-- 动态数据源 -->  
   <bean id="dynamicDataSource" class="com.sovitjs.manager.base.DynamicDataSource">  
       <!-- 通过key-value关联数据源 -->  
       <property name="targetDataSources">  
           <map>  
               <entry value-ref="dataSource" key="dataSourceKey"></entry>  
               <entry value-ref="dataSourceR1" key="dataSourceKeyR1"></entry>
           </map>  
       </property>  
       <property name="defaultTargetDataSource" ref="dataSource" />      
   </bean>
     
    <!-- 开启事务支持 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager" p:dataSource-ref="dynamicDataSource"/>
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> 
        <!--dataSource属性指定要用到的连接池--> 
        <property name="dataSource" ref="dynamicDataSource"/>
         
        <property name="mapperLocations" value="classpath:com.sovitjs.**.xml"  />
        <!--configLocation属性指定mybatis的核心配置文件 -->
        <property name="configLocation" value="classpath:Configuration.xml" /> 
    </bean>

//设置用哪个数据源
DBContextHolder.setDbType(DBContextHolder.DB_TYPE_W);
DBContextHolder.setDbType(DBContextHolder.DB_TYPE_R1);
//设置随机使用数据源
DBContextHolder.setDbType(2);//1为默认数据源