druid多数据源配置+Datasurce动态切换
AbstractRoutingDataSource 数据源动态切换
spring 使用AbstractRoutingDataSource自定义动态数据源时的事务处理, 需要继承spring的AbstractRoutingDataSource定义自己的动态数据源，可以根据需要动态的切换不同数据库的数据源，使用起来非常方便。
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public class ChooseDataSource extends AbstractRoutingDataSource { /** * 获取与数据源相关的key * 此key是Map<String,DataSource> resolvedDataSources 中与数据源绑定的key值 * 在通过determineTargetDataSource获取目标数据源时使用 */ @Override protected Object determineCurrentLookupKey() { return RouteHolder.getRouteKey(); } } |
通过容器RouteHolder存储当前线程使用的数据源的key
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/** * 保存当前线程数据源的key */ public class RouteHolder { private static ThreadLocal<String> routeKey = new ThreadLocal<String>();
/** * 获取当前线程的数据源路由的key * @return */ public static String getRouteKey() { String key = routeKey.get(); return key; } /** * 绑定当前线程数据源路由的key * 在使用完成之后，必须调用removeRouteKey()方法删除 * @param key */ public static void setRouteKey(String key) { routeKey.set(key); }
/** * 删除与当前线程绑定的数据源路由的key */ public static void removeRouteKey() { routeKey.remove(); } } |
使用spring 的aop编程在业务逻辑方法运行前将当前方法使用数据源的key从业务逻辑方法上自定义注解@DataSource中解析数据源key并添加到RouteHolder中
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/** * 执行dao方法之前的切面 * 获取datasource对象之前往RouteHolder中指定当前线程数据源路由的key * */ public class DataSourceAspect { /** * 在dao层方法之前获取datasource对象之前在切面中指定当前线程数据源路由的key */ public void before(JoinPoint point) { Object target = point.getTarget(); String method = point.getSignature().getName(); Class<?>[] classz = target.getClass().getInterfaces(); Class<?>[] parameterTypes = ((MethodSignature) point.getSignature()) .getMethod().getParameterTypes(); try { if (classz != null && classz.length > 0 ) { Method m = classz[ 0 ].getMethod(method, parameterTypes); if (m != null && m.isAnnotationPresent(DataSource. class )) { DataSource data = m.getAnnotation(DataSource. class ); RouteHolder.setRouteKey(data.value()); } } } catch (Exception e) { e.printStackTrace(); } } } |
解释：
DataSourceAspect 这个切面类，应该针对的被代理类应该是service的实现类（serviceImpl）,因为dao层用的mybatis只有一个dao层的接口，所以放在service上做处理比较好。
业务逻辑方法
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@Named ( "userService" ) public class UserService { @Inject private UserDao userDao;
@DataSource ( "master" ) @Transactional (propagation=Propagation.REQUIRED) public void updatePasswd( int userid,String passwd) { User user = new User(); user.setUserid(userid); user.setPassword(passwd); userDao.updatePassword(user); } @DataSource ( "slave" ) @Transactional (propagation=Propagation.REQUIRED) public User getUser( int userid) { User user = userDao.getUserById(userid); System.out.println( "username------:" +user.getUsername()); return user; } } |
注解类
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import java.lang.annotation.ElementType; import java.lang.annotation.Target; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; /** * RUNTIME * 编译器将把注释记录在类文件中，在运行时 VM 将保留注释，因此可以反射性地读取。 * @author jiangxm * */ @Retention (RetentionPolicy.RUNTIME) @Target (ElementType.METHOD) public @interface DataSource { String value(); } |
spring的配置文件
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< bean id = "dataSource" class = "com.westone.datasource.DbRouteDataSource" > < property name = "targetDataSources" > < map > <!-- write --> < entry key = "master" value-ref = "master" ></ entry > <!-- read --> < entry key = "slave" value-ref = "slave" ></ entry > </ map > </ property > </ bean >
< bean id = "master" class = "org.apache测试数据mons.dbcp.BasicDataSource" > < property name = "driverClassName" value = "${jdbc.driverclass}" /> < property name = "url" value = "${jdbc.masterurl}" /> < property name = "username" value = "${jdbc.username}" /> < property name = "password" value = "${jdbc.password}" /> < property name = "maxActive" value = "${jdbc.maxActive}" ></ property > < property name = "maxIdle" value = "${jdbc.maxIdle}" ></ property > < property name = "maxWait" value = "${jdbc.maxWait}" ></ property > </ bean >
< bean id = "slave" class = "org.apache测试数据mons.dbcp.BasicDataSource" > < property name = "driverClassName" value = "${jdbc.driverclass}" /> < property name = "url" value = "${jdbc.slaveurl}" /> < property name = "username" value = "${jdbc.username}" /> < property name = "password" value = "${jdbc.password}" /> < property name = "maxActive" value = "${jdbc.maxActive}" ></ property > < property name = "maxIdle" value = "${jdbc.maxIdle}" ></ property > < property name = "maxWait" value = "${jdbc.maxWait}" ></ property > </ bean >
< bean id = "sqlSessionTemplate" class = "org.mybatis.spring.SqlSessionTemplate" > < constructor-arg index = "0" ref = "sqlSessionFactory" /> </ bean > < bean id = "sqlSessionFactory" class = "org.mybatis.spring.SqlSessionFactoryBean" > < property name = "configLocation" value = "classpath:config/mybatis/mybatis.cfg.xml" ></ property > < property name = "dataSource" ref = "dataSource" /> </ bean >
<!-- 配置mapper的映射扫描器 根据包中定义的接口自动生成dao的实现类--> < bean class = "org.mybatis.spring.mapper.MapperScannerConfigurer" > < property name = "basePackage" value = "com.westone.dao" ></ property > </ bean >
<!-- 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 = "aspectBean" class = "com.westone.datasource.aspect.DataSourceAspect" ></ bean >
< aop:config > < aop:aspect id = "dataSourceAspect" ref = "aspectBean" > < aop:pointcut id = "dataSourcePoint" expression = "execution(public * com.westone.service.*.*(..))" /> < aop:before method = "beforeDaoMethod" pointcut-ref = "dataSourcePoint" /> </ aop:aspect > </ aop:config >
<!-- 事务管理器配置 --> < bean id = "transactionManager" class = "org.springframework.jdbc.datasource.DataSourceTransactionManager" > < property name = "dataSource" ref = "dataSource" /> </ bean > <!-- 开启事务注解驱动 在业务逻辑层上使用@Transactional 注解 为业务逻辑层管理事务--> < tx:annotation-driven transaction-manager = "transactionManager" /> |
事务管理配置一定要配置在往RouteHolder中注入数据源key之前 否则会报
Could not open JDBC Connection for transaction; nested exception is java.lang.IllegalStateException: Cannot determine target DataSource for lookup key [null] 找不到数据源错误。
由此就可以根据方法上的@DataSource([master]) 注解配置不同的数据源key 使用动态数据源。
解释：
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java.lang.reflect.Method.getAnnotation(Class annotationClass) |
参数：
annotationClass - Class对象对相应的注解类型，比如Datasource.class 。
返回值：
如果存在于此元素，则返回该元素注解指定的注解对象，否则返回为null
例子
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import java.lang.annotation.Annotation; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.reflect.Method; public class MethodDemo { public static void main(String[] args) { Method[] methods = SampleClass. class .getMethods(); Annotation annotation = methods[ 0 ].getAnnotation(CustomAnnotation. class ); if (annotation instanceof CustomAnnotation){ CustomAnnotation customAnnotation = (CustomAnnotation) annotation; System.out.println( "name: " + customAnnotation.name()); System.out.println( "value: " + customAnnotation.value()); } } } @CustomAnnotation (name= "SampleClass" , value = "Sample Class Annotation" ) class SampleClass { private String sampleField; @CustomAnnotation (name= "getSampleMethod" , value = "Sample Method Annotation" ) public String getSampleField() { return sampleField; } public void setSampleField(String sampleField) { this .sampleField = sampleField; } } @Retention (RetentionPolicy.RUNTIME) @interface CustomAnnotation { public String name(); public String value(); } |
编译并运行上面的程序，这将产生以下结果
-name: getSampleMethod
value: Sample Method Annotation
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getInterfaces() |
能够获得这个对象所实现的接口
配置多数据源并实现Druid自动切换
Spring Boot配置多数据源
配置yml文件
这里并没有对spring.datasource配置数据源，因为增加新数据源后，系统会覆盖由spring.datasource自动配置的内容。
这里自定义了两个数据源spring.datasource.cmmi和spring.datasource.zentao
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spring: datasource: type: com.alibaba.druid.pool.DruidDataSource base: type: com.alibaba.druid.pool.DruidDataSource driver- class -name: com.mysql.cj.jdbc.Driver initialize: true #指定初始化数据源，是否用data.sql来初始化，默认: true name: cmmi url: jdbc:mysql: //127.0.0.1:3306/cmmi?useUnicode=true&characterEncoding=utf-8&useSSL=false&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC&zeroDateTimeBehavior=convertToNull username: root password: root zentao: type: com.alibaba.druid.pool.DruidDataSource driver- class -name: com.mysql.cj.jdbc.Driver initialize: true name: zentaopro url: jdbc:mysql: //127.0.0.1:3306/zentaopro?useUnicode=true&characterEncoding=utf-8&useSSL=false&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC&zeroDateTimeBehavior=convertToNull username: root password: root |
主数据源配置
注意，配置类需要对DataSource、DataSourceTransactionManager、SqlSessionFactory 、SqlSessionTemplate四个数据项进行配置；DataSource类型需要引入javax.sql.DataSource；当系统中有多个数据源时，必须有一个数据源为主数据源，使用@Primary修饰。
@MapperScan对指定dao包建立映射，确保在多个数据源下，自动选择合适的数据源，而在service层里不需要做特殊说明。
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@Configuration @MapperScan (basePackages = "cmmi.dao.base" , sqlSessionTemplateRef = "baseSqlSessionTemplate" ) public class BaseDataSourceConfig { @Bean (name = "baseDataSource" ) @ConfigurationProperties (prefix = "spring.datasource.base" ) @Primary public DataSource setDataSource() { return DataSourceBuilder.create().build(); } @Bean (name = "baseTransactionManager" ) @Primary public DataSourceTransactionManager setTransactionManager( @Qualifier ( "baseDataSource" ) DataSource dataSource) { return new DruidDataSource(); } @Bean (name = "baseSqlSessionFactory" ) @Primary public SqlSessionFactory setSqlSessionFactory( @Qualifier ( "baseDataSource" ) DataSource dataSource) throws Exception { SqlSessionFactoryBean bean = new SqlSessionFactoryBean(); bean.setDataSource(dataSource); bean.setMapperLocations( new PathMatchingResourcePatternResolver().getResources( "classpath:mapper/base/*.xml" )); return bean.getObject(); } @Bean (name = "baseSqlSessionTemplate" ) @Primary public SqlSessionTemplate setSqlSessionTemplate( @Qualifier ( "baseSqlSessionFactory" ) SqlSessionFactory sqlSessionFactory) throws Exception { return new SqlSessionTemplate(sqlSessionFactory); } } |
从数据源配置
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@Configuration @MapperScan (basePackages = "cmmi.dao.zentao" , sqlSessionTemplateRef = "zentaoSqlSessionTemplate" ) public class ZentaoDataSourceConfig { @Bean (name = "zentaoDataSource" ) @ConfigurationProperties (prefix = "spring.datasource.zentao" ) public DataSource setDataSource() { return new DruidDataSource(); } @Bean (name = "zentaoTransactionManager" ) public DataSourceTransactionManager setTransactionManager( @Qualifier ( "zentaoDataSource" ) DataSource dataSource) { return new DataSourceTransactionManager(dataSource); } @Bean (name = "zentaoSqlSessionFactory" ) public SqlSessionFactory setSqlSessionFactory( @Qualifier ( "zentaoDataSource" ) DataSource dataSource) throws Exception { SqlSessionFactoryBean bean = new SqlSessionFactoryBean(); bean.setDataSource(dataSource); bean.setMapperLocations( new PathMatchingResourcePatternResolver().getResources( "classpath:mapper/zentao/*.xml" )); return bean.getObject(); } @Bean (name = "zentaoSqlSessionTemplate" ) public SqlSessionTemplate setSqlSessionTemplate( @Qualifier ( "zentaoSqlSessionFactory" ) SqlSessionFactory sqlSessionFactory) throws Exception { return new SqlSessionTemplate(sqlSessionFactory); } } |
使用dao
这里只需要正常使用dao就可以了，spring会根据数据源配置的映射自动选择相应数据源，而不需要在service做特殊说明。
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@Service public class TestService { private final ZtUserMapper ztUserMapper; private final LevelDic levelDic; @Autowired public TestService(ZtUserMapper ztUserMapper, LevelDic levelDic) { this .ztUserMapper = ztUserMapper; this .levelDic = levelDic; } public void test() { ztUserMapper.selectByPrimaryKey( 1 ); levelDic.setDicId( new Integer( 1 ).byteValue()); } } |
日志
o.a.c.c.C.[Tomcat].[localhost].[/cmmi] : Initializing Spring FrameworkServlet ‘dispatcherServlet'
o.s.web.servlet.DispatcherServlet : FrameworkServlet ‘dispatcherServlet': initialization started
o.s.web.servlet.DispatcherServlet : FrameworkServlet ‘dispatcherServlet': initialization completed in 23 ms
com.alibaba.druid.pool.DruidDataSource : {dataSource-1,cmmi} inited
com.alibaba.druid.pool.DruidDataSource : {dataSource-2,zentaopro} inited
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。
原文链接：https://blog.csdn.net/fragrant_no1/article/details/87803041
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