前置條件:大家在開發過程中大多都是連接一個數據庫,進行數據操作,但是在同一個項目工程中,需要連接多個數據庫,進行讀寫操作,這時候就需要配置切換動態數據源。。。,f廢話少說,直接上代碼
這裏已ssm框架爲例,當然項目所需的相關依賴jar都已經集成在框架中了。。。。
1、數據源連接參數
jdbc.properties
#mysql 5.x
jdbc.driver_1=com.mysql.jdbc.Driver
jdbc.url_1=jdbc\:mysql\://127.0.01:3306/db_xedk?autoReconnect\=true&useUnicode\=true&characterEncoding\=utf8&useSSL\=false&failOverReadOnly\=false
jdbc.username_1=root
jdbc.password_1=root
#oracle 11
jdbc.driver_2=oracle.jdbc.driver.OracleDriver
jdbc.url_2=jdbc:oracle:thin:@127.0.01:1521/ORCL
jdbc.username_2=root
jdbc.password_2=root
2、自定義數據源
package com.ssm.core.util;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
/**
* 動態數據源
* */
public class DynamicDataSource extends AbstractRoutingDataSource
{
@Override
protected Object determineCurrentLookupKey() {
return DBContextHolder.getDbType();
}
}
package com.ssm.core.util;
/**
* 數據源類型
*/
public class DBContextHolder {
/**
* 注意:數據源標識保存在線程變量中,避免多線程操作數據源時互相干擾
*/
private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
// 設置當前數據源
public static void setDbType(String dbType) {
contextHolder.set(dbType);
}
// 獲取當前數據源
public static String getDbType() {
return ((String) contextHolder.get());
}
// 清空上下文數據源
public static void clearDbType() {
contextHolder.remove();
}
}
3、配置數據源
spring-dao.xml:
<!-- 配置數據源1 -->
<bean id="dataSource1" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="${jdbc.driver_1}" />
<property name="url" value="${jdbc.url_1}" />
<property name="username" value="${jdbc.username_1}" />
<property name="password" value="${jdbc.password_1}" />
<property name="maxActive" value="10" />
<property name="minIdle" value="5" />
</bean>
<!-- 配置數據源2 -->
<bean id="dataSource2" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="${jdbc.driver_2}" />
<property name="url" value="${jdbc.url_2}" />
<property name="username" value="${jdbc.username_2}" />
<property name="password" value="${jdbc.password_2}" />
<property name="maxActive" value="10" />
<property name="minIdle" value="5" />
</bean>
<!-- 配置SqlSessionFactory,同時指定數據源 -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dynamicDataSource" />
<property name="configLocation" value="classpath:mybatis/SqlMapConfig.xml"></property>
<property name="mapperLocations" value="classpath:mybatis/sqlMap/sqlMap*.xml" />
</bean>
<!-- 配置掃描包,加載mapper代理對象 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.ssm.core.*.dao" />
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />
</bean>
spring-service.xml:
<!-- 配置多數源映射關係 -->
<bean id="dynamicDataSource" class="com.ssm.core.util.DynamicDataSource">
<property name="targetDataSources">
<map key-type="java.lang.String">
<entry value-ref="dataSource1" key="dataSource1"></entry>
<entry value-ref="dataSource2" key="dataSource2"></entry>
</map>
</property>
<!-- 默認數據源1 -->
<property name="defaultTargetDataSource" ref="dataSource1"></property>
</bean>
<!--配置事務管理器 -->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<!-- 數據源 -->
<property name="dataSource" ref="dynamicDataSource" />
</bean>
<!-- 通知 -->
<tx:advice id="txAdvice"
transaction-manager="transactionManager">
<tx:attributes>
<!-- 傳播行爲 -->
<tx:method name="save*" propagation="REQUIRED" />
<tx:method name="insert*" propagation="REQUIRED" />
<tx:method name="add*" propagation="REQUIRED" />
<tx:method name="create*" propagation="REQUIRED" />
<tx:method name="delete*" propagation="REQUIRED" />
<tx:method name="update*" propagation="REQUIRED" />
<tx:method name="find*" propagation="SUPPORTS"
read-only="true" />
<tx:method name="select*" propagation="SUPPORTS"
read-only="true" />
<tx:method name="get*" propagation="SUPPORTS"
read-only="true" />
</tx:attributes>
</tx:advice>
<!-- 切面-事務管理控制在Service層 -->
<aop:config>
<aop:advisor advice-ref="txAdvice"
pointcut="execution(* com.ssm.core.*.service.*Service.*(..))" />
</aop:config>
<context:component-scan
base-package="com.ssm.core">
<context:exclude-filter type="regex"
expression="com.ssm.core.*.*.controller.*" />
</context:component-scan>
4、使用數據源
使用方式:
DBContextHolder.setDbType("dataSource1"); //設置數據源
List<UserInfo> users = userDao.getUserInfoByMap(map); //dao調用
/**
* 查詢用戶列表_mysql
*/
public List<UserInfo> getUserListByMysql()
{
Map<String, Object> map = new HashMap<String, Object>();
//調用mysql數據源
DBContextHolder.setDbType("dataSource1");
List<UserInfo> users = userDao.getUserInfoByMap(map);
return users;
}
/**
* 查詢用戶列表_oracle
*/
public List<UserEntity> getUserEntityListByOracle()
{
Map<String, Object> map = new HashMap<String, Object>();
//調用oracle數據源
DBContextHolder.setDbType("dataSource2");
List<UserEntity> users = userDao.getUserEntityByMap(map);
return users;
}
5、測試
package com.ssm.core.pc.controller;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.lang.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import com.ssm.base.BusinessException;
import com.ssm.base.Constant;
import com.ssm.core.pc.entity.UserEntity;
import com.ssm.core.pc.entity.UserInfo;
import com.ssm.core.pc.service.UserInfoService;
import com.ssm.core.util.RedisUtil;
import com.ssm.utils.SmsUtil;
import com.ssm.utils.StringHelper;
@Controller
@RequestMapping(value = "/index")
public class TestController
{
@Autowired
private UserInfoService us;
@RequestMapping(value = "testDynamicDataSource", method = RequestMethod.POST)
@ResponseBody
public Map<String, Object> getTest(String type) throws Exception
{
Map<String, Object> rspmap = new HashMap<String, Object>();
if(StringUtils.isBlank(type)) {
throw new BusinessException("type不能爲空");
}
System.err.println("測試雙數據源start。。。。.");
List<?> list = new ArrayList<>();
if("1".equals(type)) {
System.err.println("調用mysql數據源");
list = us.getUserListByMysql();
}
if("2".equals(type)) {
System.err.println("調用oracle數據源");
list = us.getUserEntityListByOracle();
}
rspmap.put("users", list);
System.err.println("測試雙數據源end。。。。.");
return rspmap;
}
}
調用:http://localhost/ssmDemo/index/testDynamicDataSource.do?type=1
以上方法,需要使用哪個就需要設置一下,太過於繁瑣,這個使用切面編程,統一的解決使用哪個數據源。。。。
實現思路:
a、對於需要使用的dao層,加上自定義的@DataSource("dataSource2")註解
b、使用aop切面,攔截@DataSource註解層,設置對應的數據源
核心代碼:
1、自定義@DataSource註解
package com.ssm.core.util;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import java.lang.annotation.ElementType;
import java.lang.annotation.RetentionPolicy;
/**自定義@DataSource註解 */
@Target({ ElementType.TYPE,ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
public @interface DataSource {
String value();
}
2、定義DataSourceAspect切面
package com.ssm.base;
import java.lang.reflect.Method;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import com.ssm.core.util.DBContextHolder;
import com.ssm.core.util.DataSource;
/**
* DataSource切面
*/
@Component
@Aspect
public class DataSourceAspect {
private static final Logger logger = LoggerFactory.getLogger(DataSourceAspect.class);
// 指定切入點表單式
@Pointcut("execution(* com.ssm.core.pc.dao..*.*(..))")
public void pointCut_() {
}
// 前置通知 : 在執行目標方法之前執行
@Before("pointCut_()")
public void begin(JoinPoint point) {
System.err.println("正在設置數據源。。。");
//獲取由@DataSource指定的數據源標識,設置到線程存儲中以便切換數據源
Class<?> target = point.getTarget().getClass();
MethodSignature signature = (MethodSignature) point.getSignature();
// 默認使用目標類型的註解,如果沒有則使用其實現接口的註解
for (Class<?> clazz : target.getInterfaces()) {
resolveDataSource(clazz, signature.getMethod());
}
resolveDataSource(target, signature.getMethod());
}
// 後置/最終通知:在執行目標方法之後執行 【無論是否出現異常最終都會執行】
@After("pointCut_()")
public void after(JoinPoint point) {
DBContextHolder.clearDbType();
System.out.println("切換默認數據源成功");
}
/**
* 提取目標對象方法註解和類型註解中的數據源標識
*
* @param clazz
* @param method
*/
private void resolveDataSource(Class<?> clazz, Method method) {
try {
Class<?>[] types = method.getParameterTypes();
// 默認使用類型註解
if (clazz.isAnnotationPresent(DataSource.class)) {
DataSource source = clazz.getAnnotation(DataSource.class);
DBContextHolder.setDbType(source.value());
}
// 方法註解可以覆蓋類型註解
Method m = clazz.getMethod(method.getName(), types);
if (m != null && m.isAnnotationPresent(DataSource.class)) {
DataSource source = m.getAnnotation(DataSource.class);
DBContextHolder.setDbType(source.value());
logger.debug("當前數據源:"+source.value());
}
} catch (Exception e) {
logger.error(clazz + ":" + e.getMessage());
}
}
}
在spring-dao.xml,
<!-- 開啓aop註解方式 -->
<aop:aspectj-autoproxy proxy-target-class="true"></aop:aspectj-autoproxy>
在對應的dao層使用
@DataSource("dataSource2")
public interface UserEntityDao {
List<UserEntity> getUserEntityByMap(Map<String, Object> map);
}
調用成功,截圖如下