spring 更换数据库

spring 解析之切换数据源-mysql实现版本

java探案

2017-06-08 13:13:26

主要思想：自定义一个注解,此注解标注在办法上,通过反射解析出办法所在的类,遍历这个类里的所有办法,找到注解所对应的那个办法,调用invoke,执行办法的过程中,用threadLocal存储的数据源名字进行动态切换.下面进行详细讲解：

1. 自定义一个注解,作用是标注办法

1. package com.tiangou.annotation;

2. import java.lang.annotation.Documented;

3. import java.lang.annotation.ElementType;

4. import java.lang.annotation.Retention;

5. import java.lang.annotation.RetentionPolicy;

6. import java.lang.annotation.Target;

7. @Documented

8. @Retention(RetentionPolicy.RUNTIME)

9. @Target(ElementType.METHOD)

10. public @interface DataSource {

11. String name() default "";

12. }

2.ThreadLocal保留数据库

1. package com.tiangou.dataSource;

2. public class DataSourceContextHolder {

1. private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();

2. public static void setDbType(String dbType) {

3.AbstractRoutingDataSource spring动态切换数据源

1. contextHolder.set(dbType);

2. }

3. public static String getDbType() {

4. return ((String) contextHolder.get());

5. }

6. public static void clearDbType() {

7. contextHolder.remove();

8. }

9. }

10. package com.tiangou.dataSource;

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

12. public class DynamicDataSource extends AbstractRoutingDataSource{

13. @Override

14. protected Object determineCurrentLookupKey() {

15. System.out.println(DataSourceContextHolder.getDbType());

16. return DataSourceContextHolder.getDbType();

17. }

18. }

4.配置文件中配置aop切面

<?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:aop="http://www.springframework.org/schema/aop"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:jee="http://www.springframework.org/schema/jee"

xmlns:tx="http://www.springframework.org/schema/tx"

xsi:schemaLocation="

http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd

http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd

http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd

http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-4.0.xsd

http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

<!-- 配置数据源 -->

<import resource="classpath*:mongodb.xml" />

<import resource="classpath*:redis.xml" />

<!-- <import resource="classpath*:rabbitMq.xml" /> -->

<aop:aspectj-autoproxy proxy-target-class="true"/>

<!-- 使用注解的包,包含子集 -->

<bean id="db1"

class="com.alibaba.druid.pool.DruidDataSource">

<property name="url" value="jdbc:mysql://localhost:3306/tiangou?useUnicode=true&amp;characterEncoding=UTF-8"/>

<property name="username" value="root"/>

<property name="password" value="root"/>

</bean>

<bean id="db2"

class="com.alibaba.druid.pool.DruidDataSource">

<property name="url" value="jdbc:mysql://localhost:3306/tiangou2?useUnicode=true&amp;characterEncoding=UTF-8"/>

<property name="username" value="root"/>

<property name="password" value="root"/>

</bean>

<bean id="dataSource" class="com.tiangou.dataSource.DynamicDataSource">

<property name="targetDataSources">

<map key-type="java.lang.String">

<entry key="db1" value-ref="db1" />

<entry key="db2" value-ref="db2" />

</map>

</property>

<property name="defaultTargetDataSource" ref="db1" />

</bean>

<!-- 配置mybatis的sqlSessionFactory -->

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">

<property name="dataSource" ref="dataSource" />

<!-- 自动扫描mappers.xml文件 -->

<property name="mapperLocations" value="classpath:com/tiangou/mapper/*.xml"></property>

<!-- mybatis配置文件 -->

<property name="configLocation" value="classpath:mybatis-config.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.tiangou.mapper" />

<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>

</bean>

<!-- 开启事务注解驱动 -->

<tx:annotation-driven proxy-target-class="true" order="2" />

<!-- (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>

<!-- 配置事务通知属性 -->

<tx:advice id="txAdvice" transaction-manager="transactionManager">

<!-- 定义事务传播属性 -->

<tx:attributes>

<tx:method name="insert*" propagation="REQUIRED" />

<tx:method name="update*" propagation="REQUIRED" />

<tx:method name="edit*" propagation="REQUIRED" />

<tx:method name="save*" propagation="REQUIRED" />

<tx:method name="add*" propagation="REQUIRED" />

<tx:method name="new*" propagation="REQUIRED" />

<tx:method name="set*" propagation="REQUIRED" />

<tx:method name="remove*" propagation="REQUIRED" />

<tx:method name="delete*" propagation="REQUIRED" />

<tx:method name="change*" propagation="REQUIRED" />

<tx:method name="check*" propagation="REQUIRED" />

<tx:method name="get*" propagation="REQUIRED"/>

<tx:method name="find*" propagation="REQUIRED" />

<tx:method name="load*" propagation="REQUIRED"/>

<tx:method name="*" propagation="REQUIRED" />

</tx:attributes>

</tx:advice>

<!-- SpringMVC在超出上传文件限制时,会抛出

org.springframework.web.multipart.MaxUploadSizeExceededException -->

<!-- 该异常是SpringMVC在检查上传的文件信息时抛出来的,而且此时还没有进入到Controller办法中 -->

<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">

<property name="exceptionMappings">

<props>

<!-- 遇到

MaxUploadSizeExceededException异常时,自动跳转到

/WEB-INF/error_fileupload.jsp页面 -->

<prop key="org.springframework.web.multipart.MaxUploadSizeExceededException">WEB-INF/error_fileupload</prop>

<!-- 处理其它异常(包含Controller抛出的) -->

<prop key="java.lang.Throwable">WEB-INF/500</prop>

</props>

</property>

</bean>

<!-- 配置事务切面 -->

<aop:config>

<aop:pointcut id="serviceOperation"

expression="execution(* com.tiangou.service.*.*(..))" />

<aop:advisor advice-ref="txAdvice" pointcut-ref="serviceOperation" />

</aop:config>

<!--

shiroQUANXIAN

-->

<!-- 继承自AuthorizingRealm的自定义Realm,即指定Shiro验证用户登录的类为自定义的ShiroDbRealm.java -->

<!-- <bean id="myRealm" class="com.tiangou.realm.MyRealm"/> -->

<!-- Shiro默认会使用Servlet容器的Session,可通过sessionMode属性来指定使用Shiro原生Session -->

<!-- 即<property name="sessionMode" value="native"/>,详细说明见官方文档 -->

<!-- 这里主要是设置自定义的单Realm应用,若有多个Realm,可使用'realms'属性代替 -->

<!-- <bean id="securityManager" class="org.apache.shiro.web.mgt.DefaultWebSecurityManager"> -->

<!-- <property name="realm" ref="myRealm"/> -->

<!-- </bean> -->

<!-- Shiro主过滤器自己功能十分强大,其强大之处就在于它支持任何基于URL路径表达式的、自定义的过滤器的执行 -->

<!-- Web应用中,Shiro可控制的Web哀求必须经过Shiro主过滤器的拦截,Shiro对基于Spring的Web应用提供了完美的支持 -->

<!-- <bean id="shiroFilter" class="org.apache.shiro.spring.web.ShiroFilterFactoryBean"> -->

<!-- Shiro的核心平安接口,这个属性是必须的 -->

<!-- <property name="securityManager" ref="securityManager"/> -->

<!-- 要求登录时的链接(可根据项目的URL进行替换),非必需的属性,默认会自动寻找Web工程根目录下的"/login.jsp"页面 -->

<!-- <property name="loginUrl" value="/"/> -->

<!-- 登录成功后要跳转的连接(本例中此属性用不到,因为登录成功后的处理逻辑在LoginController里硬编码为main.jsp了) -->

<!-- <property name="successUrl" value="/system/main"/> -->

<!-- 用户拜访未对其授权的资源时,所显示的连接 -->

<!-- 若想更明显的测试此属性可以修改它的值,如unauthor.jsp,然后用[玄玉]登录后拜访/admin/listUser.jsp就看见浏览器会显示unauthor.jsp -->

<!-- <property name="unauthorizedUrl" value="/"/> -->

<!-- Shiro连接约束配置,即过滤链的定义 -->

<!-- 此处可配合我的这篇文章来理解各个过滤连的作用

http://blog.csdn.net/jadyer/article/details/12172839 -->

<!-- 下面value值的第一个'/'代表的路径是相对于

HttpServletRequest.getContextPath()的值来的 -->

<!-- anon：它对应的过滤器里面是空的,什么都没做,这里.do和.jsp后面的*表示参数,比喻说login.jsp?main这种 -->

<!-- authc：该过滤器下的页面必须验证后才能拜访,它是Shiro内置的一个拦截器

org.apache.shiro.web.filter.authc.FormAuthenticationFilter -->

<!-- <property name="filterChainDefinitions"> -->

<!-- <value> -->

<!-- /mydemo/login=anon -->

<!-- /mydemo/getVerifyCodeImage=anon -->

<!-- /main**=authc -->

<!-- /user/info**=authc -->

<!-- /admin/listUser**=authc,perms[admin:manage] -->

<!-- </value> -->

<!-- </property> -->

<!-- </bean> -->

<!-- 保证实现了Shiro内部lifecycle函数的bean执行 -->

<!-- <bean id="lifecycleBeanPostProcessor" class="org.apache.shiro.spring.LifecycleBeanPostProcessor"/> -->

<!-- 开启Shiro的注解(如@RequiresRoles,@RequiresPermissions),需借助SpringAOP扫描使用Shiro注解的类,并在必要时进行平安逻辑验证 -->

<!-- 配置以下两个bean即可实现此功能 -->

<!-- Enable Shiro Annotations for Spring-configured beans. Only run after the lifecycleBeanProcessor has run -->

<!-- 由于本例中并未使用Shiro注解,故注释掉这两个bean(个人觉得将权限通过注解的方式硬编码在程序中,查看起来不是很方便,没需要使用) -->

<!--

<bean class="org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyCreator" depends-on="lifecycleBeanPostProcessor"/>

<bean class="org.apache.shiro.spring.security.interceptor.AuthorizationAttributeSourceAdvisor">

<property name="securityManager" ref="securityManager"/>

</bean> -->

<!-- 自动扫描 -->

<context:component-scan base-package="com.tiangou.service,com.tiangou.aop" />

<context:component-scan base-package="com.tiangou.websocket" />

</beans>

5.对调用的办法上进行辨别,切换数据源

以上就是动态切换数据源的讲解,必要源码的私信我,喜欢小编的给我一波关注,谢谢.