spring boot 动态切换数据源（数据源信息从数据库中读取）

项目要求从多个源库(oracle,haha,pg)里面读取schema,table，字段等信息，spring提供了AbstractRoutingDataSource类实现动态数据源，下面就简单介绍一下如何实现的。

首先给出数据源信息表如下所示：

ID	NAME	DATABASE_TYPE	CON_STR	ACCOUNT	PASSWORD	CREATOR	CREATE_TIME	MODIFIER	MODIFY_TIME	DEL_FLAG
2	xxx2	HANA	jdbc:sap://1.1.1.1:30015	xxx	xxx	xxx	2021/11/10 20:35	xxx	2021/11/9 20:35	0
3	xxx3	oracle	jdbc:oracle:thin:@1.1.1.1:1521:xxx	xxx	xxx	xxx	2021/11/10 20:35	xxx	2021/11/10 20:35	0
4	xxx4	oracle	jdbc:oracle:thin:@1.1.1.1:1521:xxx	xxx	xxx	xxx	2021/11/11 20:35	xxx	2021/11/11 20:35	0
5	xxx5	HANA	jdbc:sap://1.1.1.1:30015	xxx	xxx	xxx	2021/11/12 20:35	xxx	2021/11/12 20:35	0
6	xxx6	oracle	jdbc:oracle:thin:@1.1.1.1:1521:xxx	xxx	xxx	xxx	2021/11/13 20:35	xxx	2021/11/13 20:35	0
7	xxx7	HANA	jdbc:sap://1.1.1.1:30015	xxx	xxx	xxx	2021/11/14 20:35	xxx	2021/11/14 20:35	0

在项目中可以通过上表读取数据源信息进行数据源的实时切换,对于的entity对象为：

package com.xxx.entity;import lombok.Data;
import lombok.ToString;/*** @Author : lgq* @CreateTime : 2021/11/16* @Description :**/
@Data
@ToString
public class DataSource {String datasourceId;String url;String userName;String passWord;String dataSourceName;String databaseType;
}

DynamicDataSource继承AbstractRoutingDataSource用来创建和维护数据源。

package com.xxx.datasource;import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Map;
import java.util.Set;import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.stat.DruidDataSourceStatManager;
import com.xxx.common.errorcode.ErrorCode;
import com.xxx.common.exception.BusinessException;
import com.xxx.entity.DataSource;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import org.springframework.util.StringUtils;public class DynamicDataSource extends AbstractRoutingDataSource {private boolean debug = true;public static final Logger log = LoggerFactory.getLogger(DynamicDataSource.class);private Map<Object, Object> dynamicTargetDataSources;private Object dynamicDefaultTargetDataSource;@Overrideprotected Object determineCurrentLookupKey() {String datasource = DBContextHolder.getDataSource();if (!StringUtils.isEmpty(datasource)) {Map<Object, Object> dynamicTargetDataSources2 = this.dynamicTargetDataSources;if (dynamicTargetDataSources2.containsKey(datasource)) {log.info("---当前数据源：" + datasource + "---");} else {log.info("不存在的数据源：");throw new BusinessException(ErrorCode.DATA_SOURCE_NOT_EXIST, "数据源：" + datasource + "不存在！");}} else {log.info("---当前数据源：默认数据源---");}return datasource;}@Overridepublic void setTargetDataSources(Map<Object, Object> targetDataSources) {super.setTargetDataSources(targetDataSources);this.dynamicTargetDataSources = targetDataSources;}// 创建数据源public boolean createDataSource(String key, String driveClass, String url, String username, String password, String databaseType) {try {/*** 排除连接不上的错误*/try {Class.forName(driveClass);DriverManager.getConnection(url, username, password);// 相当于连接数据库} catch (Exception e) {log.error("数据源：" + key + "连接数据库失败！");return false;}@SuppressWarnings("resource")
//            HikariDataSource druidDataSource = new HikariDataSource();DruidDataSource druidDataSource = new DruidDataSource();druidDataSource.setName(key);druidDataSource.setDriverClassName(driveClass);druidDataSource.setUrl(url);druidDataSource.setUsername(username);druidDataSource.setPassword(password);//初始化时建立物理连接的个数。初始化发生在显示调用init方法，或者第一次getConnection时druidDataSource.setInitialSize(1);//最大连接池数量druidDataSource.setMaxActive(20);//获取连接时最大等待时间，单位毫秒。当链接数已经达到了最大链接数的时候，应用如果还要获取链接就会出现等待的现象，// 等待链接释放并回到链接池，如果等待的时间过长就应该踢掉这个等待，不然应用很可能出现雪崩现象druidDataSource.setMaxWait(60000);//最小连接池数量druidDataSource.setMinIdle(5);//默认的验证语句String validationQuery = "select 1 from dual";if("mysql".equalsIgnoreCase(databaseType)) {validationQuery = "select 1";} else if("oracle".equalsIgnoreCase(databaseType)){//是否缓存preparedStatement，也就是PSCache。PSCache对支持游标的数据库性能提升巨大，比如说oracle。在mysql下建议关闭。druidDataSource.setPoolPreparedStatements(true);druidDataSource.setMaxPoolPreparedStatementPerConnectionSize(50);int sqlQueryTimeout = 6000;//对于耗时长的查询sql，会受限于ReadTimeout的控制，单位毫秒druidDataSource.setConnectionProperties("oracle.net.CONNECT_TIMEOUT=6000;oracle.jdbc.ReadTimeout="+sqlQueryTimeout);} else if("sqlserver2000".equalsIgnoreCase(databaseType)){validationQuery = "select 1";} else if("sqlserver".equalsIgnoreCase(databaseType)){validationQuery = "select 1";} else if("hana".equalsIgnoreCase(databaseType)){validationQuery = "select 1 from dummy";} else if("pg".equalsIgnoreCase(databaseType)){validationQuery = "select version()";}//申请连接时执行validationQuery检测连接是否有效，这里建议配置为TRUE，防止取到的连接不可用druidDataSource.setTestOnBorrow(true);//建议配置为true，不影响性能，并且保证安全性。申请连接的时候检测，如果空闲时间大于timeBetweenEvictionRunsMillis，执行validationQuery检测连接是否有效。druidDataSource.setTestWhileIdle(true);//用来检测连接是否有效的sql，要求是一个查询语句。如果validationQuery为null，testOnBorrow、testOnReturn、testWhileIdle都不会起作用。druidDataSource.setValidationQuery(validationQuery);//属性类型是字符串，通过别名的方式配置扩展插件，常用的插件有：监控统计用的filter:stat日志用的filter:log4j防御sql注入的filter:walldruidDataSource.setFilters("stat");//配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒druidDataSource.setTimeBetweenEvictionRunsMillis(60000);//配置一个连接在池中最小生存的时间，单位是毫秒，这里配置为3分钟180000druidDataSource.setMinEvictableIdleTimeMillis(180000);//打开druid.keepAlive之后，当连接池空闲时，池中的minIdle数量以内的连接，空闲时间超过minEvictableIdleTimeMillis，则会执行keepAlive操作，// 即执行druid.validationQuery指定的查询SQL，一般为select * from dual，只要minEvictableIdleTimeMillis设置的小于防火墙切断连接时间，// 就可以保证当连接空闲时自动做保活检测，不会被防火墙切断druidDataSource.setKeepAlive(true);//是否移除泄露的连接/超过时间限制是否回收。druidDataSource.setRemoveAbandoned(true);//泄露连接的定义时间(要超过最大事务的处理时间)；单位为秒。这里配置为1小时druidDataSource.setRemoveAbandonedTimeout(3600);//移除泄露连接发生是是否记录日志druidDataSource.setLogAbandoned(true);druidDataSource.init();this.dynamicTargetDataSources.put(key, druidDataSource);// 将map赋值给父类的TargetDataSourcessetTargetDataSources(this.dynamicTargetDataSources);// 将TargetDataSources中的连接信息放入resolvedDataSources管理super.afterPropertiesSet();log.info(key + "数据源初始化成功");//log.info(key+"数据源的概况："+druidDataSource.dump());return true;} catch (Exception e) {log.error(e + "");throw new BusinessException(ErrorCode.DATA_SOURCE_INIT_ERROR, "数据源：" + key + "初始化失败！");}}// 删除数据源public boolean delDataSource(String dataSourceId) {Map<Object, Object> dynamicTargetDataSources2 = this.dynamicTargetDataSources;if (dynamicTargetDataSources2.containsKey(dataSourceId)) {Set<DruidDataSource> druidDataSourceInstances = DruidDataSourceStatManager.getDruidDataSourceInstances();for (DruidDataSource ds : druidDataSourceInstances) {if (dataSourceId.equals(ds.getName())) {dynamicTargetDataSources2.remove(dataSourceId);DruidDataSourceStatManager.removeDataSource(ds);// 将map赋值给父类的TargetDataSourcessetTargetDataSources(dynamicTargetDataSources2);// 将TargetDataSources中的连接信息放入resolvedDataSources管理super.afterPropertiesSet();return true;}}}return false;}// 测试数据源连接是否有效public boolean testDatasource(String key, String driveClass, String url, String username, String password) {try {Class.forName(driveClass);DriverManager.getConnection(url, username, password);return true;} catch (Exception e) {return false;}}@Overridepublic void setDefaultTargetDataSource(Object defaultTargetDataSource) {super.setDefaultTargetDataSource(defaultTargetDataSource);this.dynamicDefaultTargetDataSource = defaultTargetDataSource;}/*** @param debug the debug to set*/public void setDebug(boolean debug) {this.debug = debug;}/*** @return the debug*/public boolean isDebug() {return debug;}/*** @return the dynamicTargetDataSources*/public Map<Object, Object> getDynamicTargetDataSources() {return dynamicTargetDataSources;}/*** @param dynamicTargetDataSources the dynamicTargetDataSources to set*/public void setDynamicTargetDataSources(Map<Object, Object> dynamicTargetDataSources) {this.dynamicTargetDataSources = dynamicTargetDataSources;}/*** @return the dynamicDefaultTargetDataSource*/public Object getDynamicDefaultTargetDataSource() {return dynamicDefaultTargetDataSource;}/*** @param dynamicDefaultTargetDataSource the dynamicDefaultTargetDataSource to set*/public void setDynamicDefaultTargetDataSource(Object dynamicDefaultTargetDataSource) {this.dynamicDefaultTargetDataSource = dynamicDefaultTargetDataSource;}/*** 检查数据源状态，没有创建或失效时重新创建* @param dataSource 数据源* @throws Exception*/public void createDataSourceWithCheck(DataSource dataSource) throws Exception {String datasourceName = dataSource.getDataSourceName();log.info("正在检查数据源：" + datasourceName);Map<Object, Object> dynamicTargetDataSources2 = this.dynamicTargetDataSources;if (dynamicTargetDataSources2.containsKey(datasourceName)) {log.info("数据源" + datasourceName + "之前已经创建，准备测试数据源是否正常...");DruidDataSource druidDataSource = (DruidDataSource) dynamicTargetDataSources2.get(datasourceName);boolean rightFlag = true;Connection connection = null;try {log.info(datasourceName + "数据源的概况->当前闲置连接数：" + druidDataSource.getPoolingCount());long activeCount = druidDataSource.getActiveCount();log.info(datasourceName + "数据源的概况->当前活动连接数：" + activeCount);if (activeCount > 0) {log.info(datasourceName + "数据源的概况->活跃连接堆栈信息：" + druidDataSource.getActiveConnectionStackTrace());}log.info("准备获取数据库连接...");connection = druidDataSource.getConnection();log.info("数据源" + datasourceName + "正常");} catch (Exception e) {//把异常信息打印到日志文件log.error(e.getMessage(), e);rightFlag = false;log.info("缓存数据源" + datasourceName + "已失效，准备删除...");if (delDataSource(datasourceName)) {log.info("缓存数据源删除成功");} else {log.info("缓存数据源删除失败");}} finally {if (null != connection) {connection.close();}}if (rightFlag) {log.info("不需要重新创建数据源");return;} else {log.info("准备重新创建数据源...");createDataSource(dataSource);log.info("重新创建数据源完成");}} else {createDataSource(dataSource);}}/*** 创建数据源* @param dataSource 数据源*/private void createDataSource(DataSource dataSource) {String datasourceName = dataSource.getDataSourceName();log.info("准备创建数据源" + datasourceName);String databaseType = dataSource.getDatabaseType();String username = dataSource.getUserName();String password = dataSource.getPassWord();String url = dataSource.getUrl();// 默认的驱动类String driveClass = "oracle.jdbc.driver.OracleDriver";if ("mysql".equalsIgnoreCase(databaseType)) {driveClass = "com.mysql.jdbc.Driver";} else if ("gp".equalsIgnoreCase(databaseType)) {driveClass = "org.postgresql.Driver";} else if ("sqlserver2000".equalsIgnoreCase(databaseType)) {driveClass = "com.microsoft.jdbc.sqlserver.SQLServerDriver";} else if ("sqlserver".equalsIgnoreCase(databaseType)) {driveClass = "com.microsoft.sqlserver.jdbc.SQLServerDriver";} else if ("hana".equalsIgnoreCase(databaseType)) {driveClass = "com.sap.db.jdbc.Driver";}if (testDatasource(datasourceName, driveClass, url, username, password)) {boolean result = this.createDataSource(datasourceName, driveClass, url, username, password, databaseType);if (!result) {log.error("数据源" + datasourceName + "配置正确，但是创建失败");throw new BusinessException(ErrorCode.DATA_SOURCE_CREATE_ERROR, "数据源 "+ datasourceName +" 配置正确，但是创建失败");}} else {log.error("数据源配置有错误");throw new BusinessException(ErrorCode.DATA_SOURCE_CONFIG_ERROR, "数据源 "+ datasourceName +" 配置错误");}}}

DruidDBConfig类用来注入动态数据源对象并创建主数据源。

package com.xxx.config;import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;import javax.sql.DataSource;import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import com.xxx.datasource.DynamicDataSource;import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.transaction.annotation.EnableTransactionManagement;/*** @Author : lgq* @CreateTime : 2021/11/15* @Description :**/
@Configuration
@EnableTransactionManagement
public class DruidDBConfig {private final Logger log = LoggerFactory.getLogger(getClass());// 数据库连接信息@Value("${spring.datasource.url}")private String dbUrl;@Value("${spring.datasource.username}")private String username;@Value("${spring.datasource.password}")private String password;@Value("${spring.datasource.driverClassName}")private String driverClassName;// 连接池连接信息@Value("${spring.datasource.initialSize}")private int initialSize;@Value("${spring.datasource.minIdle}")private int minIdle;@Value("${spring.datasource.maxActive}")private int maxActive;@Value("${spring.datasource.maxWait}")private int maxWait;@Bean // 声明其为Bean实例@Primary // 在同样的DataSource中，首先使用被标注的DataSource@Qualifier("mainDataSource")public DataSource dataSource() throws SQLException {DruidDataSource datasource = new DruidDataSource();// 基础连接信息datasource.setUrl(this.dbUrl);datasource.setUsername(username);datasource.setPassword(password);datasource.setDriverClassName(driverClassName);// 连接池连接信息datasource.setInitialSize(initialSize);datasource.setMinIdle(minIdle);datasource.setMaxActive(maxActive);datasource.setMaxWait(maxWait);//是否缓存preparedStatement，也就是PSCache。PSCache对支持游标的数据库性能提升巨大，比如说oracle。在mysql下建议关闭。datasource.setPoolPreparedStatements(true);datasource.setMaxPoolPreparedStatementPerConnectionSize(20);// 对于耗时长的查询sql，会受限于ReadTimeout的控制，单位毫秒//  datasource.setConnectionProperties("oracle.net.CONNECT_TIMEOUT=6000;oracle.jdbc.ReadTimeout=60000");//对于耗时长的查询sql，会受限于ReadTimeout的控制，单位毫秒datasource.setConnectionProperties("druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000");//申请连接时执行validationQuery检测连接是否有效，这里建议配置为TRUE，防止取到的连接不可用datasource.setTestOnBorrow(true);//建议配置为true，不影响性能，并且保证安全性。申请连接的时候检测，如果空闲时间大于timeBetweenEvictionRunsMillis，执行validationQuery检测连接是否有效。datasource.setTestWhileIdle(true);String validationQuery = "select 1 from dual";//用来检测连接是否有效的sql，要求是一个查询语句。如果validationQuery为null，testOnBorrow、testOnReturn、testWhileIdle都不会起作用。datasource.setValidationQuery(validationQuery);//属性类型是字符串，通过别名的方式配置扩展插件，常用的插件有：监控统计用的filter:stat日志用的filter:log4j防御sql注入的filter:walldatasource.setFilters("stat,wall");//配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒datasource.setTimeBetweenEvictionRunsMillis(60000);//配置一个连接在池中最小生存的时间，单位是毫秒，这里配置为3分钟180000datasource.setMinEvictableIdleTimeMillis(180000);//打开druid.keepAlive之后，当连接池空闲时，池中的minIdle数量以内的连接，空闲时间超过minEvictableIdleTimeMillis，则会执行keepAlive操作，// 即执行druid.validationQuery指定的查询SQL，一般为select * from dual，只要minEvictableIdleTimeMillis设置的小于防火墙切断连接时间，// 就可以保证当连接空闲时自动做保活检测，不会被防火墙切断datasource.setKeepAlive(true);//是否移除泄露的连接/超过时间限制是否回收。datasource.setRemoveAbandoned(true);//泄露连接的定义时间(要超过最大事务的处理时间)；单位为秒。这里配置为1小时datasource.setRemoveAbandonedTimeout(3600);//移除泄露连接发生是是否记录日志datasource.setLogAbandoned(true);return datasource;}/*** 注册一个StatViewServlet    druid监控页面配置1-帐号密码配置** @return servlet registration bean*/@Beanpublic ServletRegistrationBean druidStatViewServlet() {ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");servletRegistrationBean.addInitParameter("loginUsername", "admin");servletRegistrationBean.addInitParameter("loginPassword", "123456");servletRegistrationBean.addInitParameter("resetEnable", "false");return servletRegistrationBean;}/*** 注册一个：filterRegistrationBean   druid监控页面配置2-允许页面正常浏览** @return filter registration bean*/@Beanpublic FilterRegistrationBean druidStatFilter() {FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new WebStatFilter());// 添加过滤规则.filterRegistrationBean.addUrlPatterns("/*");// 添加不需要忽略的格式信息.filterRegistrationBean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");return filterRegistrationBean;}@Bean(name = "dynamicDataSource")@Qualifier("dynamicDataSource")public DynamicDataSource dynamicDataSource() throws SQLException {DynamicDataSource dynamicDataSource = new DynamicDataSource();dynamicDataSource.setDebug(false);//配置缺省的数据源// 默认数据源配置 DefaultTargetDataSourcedynamicDataSource.setDefaultTargetDataSource(dataSource());Map<Object, Object> targetDataSources = new HashMap<Object, Object>();//额外数据源配置 TargetDataSourcestargetDataSources.put("mainDataSource", dataSource());dynamicDataSource.setTargetDataSources(targetDataSources);return dynamicDataSource;}@Beanpublic SqlSessionFactory sqlSessionFactory() throws Exception {SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();sqlSessionFactoryBean.setDataSource(dynamicDataSource());//解决手动创建数据源后字段到bean属性名驼峰命名转换失效的问题sqlSessionFactoryBean.setConfiguration(configuration());// 设置mybatis的主配置文件ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();// 设置别名包sqlSessionFactoryBean.setTypeAliasesPackage("com.xxx.mapper");//手动配置mybatis的mapper.xml资源路径,如果单纯使用注解方式,不需要配置该行sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath:mapper/*.xml"));return sqlSessionFactoryBean.getObject();}/*** 读取驼峰命名设置** @return*/@Bean@ConfigurationProperties(prefix = "mybatis.configuration")public org.apache.ibatis.session.Configuration configuration() {return new org.apache.ibatis.session.Configuration();}}

配置文件application.properties内容如下：

server.port = xxxx
server.address = 0.0.0.0
mybatis.mapper-locations = classpath:mapper/*.xml,classpath:mapper/*/*.xml,classpath:mapper/*/*/*.xmlspring.datasource.druid.url = jdbc:oracle:thin:@1.1.1.1:1521:xxx
spring.datasource.druid.username = xxx
spring.datasource.druid.password = xxx
spring.datasource.druid.driver-class-name = oracle.jdbc.driver.OracleDriver
spring.datasource.druid.type = com.alibaba.druid.pool.DruidDataSource
spring.datasource.druid.initial-size = 20
spring.datasource.druid.max-active = 20
spring.datasource.druid.min-idle = 10
spring.datasource.druid.max-wait = 100#redis配置
purist.redis.enable = true
purist.redis.database = 0
purist.redis.host = 127.0.0.1
purist.redis.port = 6379
purist.redis.password =
purist.redis.timeout = 60000
purist.redis.pool.maxActive = 8
purist.redis.pool.maxIdle = 8
purist.redis.pool.maxWait = -1
purist.redis.pool.minIdle = 0#采用驼峰标识，解决 Mybatis resultType返回结果为null的问题
mybatis.configuration.map-underscore-to-camel-case = true

DBContextHolder使用ThreadLocal将数据源连接存储在当前线程的threadlocals(ThreadLocalMap)中，在连接数据库时自动获取当前线程对于的数据源。

package com.xxx.datasource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;/*** @Author : lgq* @CreateTime : 2021/11/16* @Description :**/
public class DBContextHolder {private final static Logger log = LoggerFactory.getLogger(DBContextHolder.class);// 对当前线程的操作-线程安全的private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();// 调用此方法，切换数据源public static void setDataSource(String dataSource) {contextHolder.set(dataSource);log.info("已切换到数据源:{}",dataSource);}// 获取数据源public static String getDataSource() {return contextHolder.get();}// 删除数据源public static void clearDataSource() {contextHolder.remove();log.info("已切换到主数据源");}}

DBChangeService提供方法手动实现数据库切换。

package com.xxx.service.sourcesystem;import java.util.List;import com.xxx.entity.DataSource;/*** @Author : lgq* @CreateTime : 2021/11/15* @Description :**/public interface DBChangeService {List<DataSource> get();boolean changeDb(String datasourceId) throws Exception;}package com.xxx.service.sourcesystem.impl;import java.util.List;import javax.annotation.Resource;import com.xxx.datasource.DBContextHolder;
import com.xxx.datasource.DynamicDataSource;
import com.xxx.entity.DataSource;
import com.xxx.mapper.DataSourceMapper;
import com.xxx.service.sourcesystem.DBChangeService;import org.springframework.stereotype.Service;/*** @Author : lgq* @CreateTime : 2021/11/16* @Description :**/
@Service
public class DBChangeServiceImpl implements DBChangeService {@ResourceDataSourceMapper dataSourceMapper;@Resourceprivate DynamicDataSource dynamicDataSource;@Overridepublic List<DataSource> get() {return dataSourceMapper.getAllDataSources();}@Overridepublic boolean changeDb(String datasourceName) throws Exception {//默认切换到主数据源,进行整体资源的查找DBContextHolder.clearDataSource();List<DataSource> dataSourcesList = dataSourceMapper.getAllDataSources();for (DataSource dataSource : dataSourcesList) {if (dataSource.getDataSourceName().equals(datasourceName)) {DynamicDataSource.log.info("需要使用的的数据源已经找到,datasourceName是：" + dataSource.getDataSourceName());//创建数据源连接&检查 若存在则不需重新创建dynamicDataSource.createDataSourceWithCheck(dataSource);//切换到该数据源DBContextHolder.setDataSource(dataSource.getDataSourceName());return true;}}return false;}}

在impl类里面的查询操作前后只要切换数据源即可完成查询。

dbChangeService.changeDb(sourceSystemName);/*
* 各种逻辑处理和查询操作
*///切回主数据源
DBContextHolder.clearDataSource();

最后，给出再贴出hana,gp,oracle查询schema和table等相关信息的语句。

<!-- gp --><!-- gp查询schema -->
<select id="getSchemaNameList"  resultType="java.lang.String">SELECT DISTINCT SCHEMA_NAME FROM "SYS"."M_TABLES"limit #{pageSize,jdbcType=DECIMAL} offset #{pageNo,jdbcType=DECIMAL}
</select>
<select id="getSchemaNameTotal"  resultType="java.lang.Long">SELECT count(DISTINCT SCHEMA_NAME) FROM "SYS"."M_TABLES"
</select><!-- gp查询table-->
<select id="getTableNameList"  resultType="java.lang.String">SELECT TABLE_NAME FROM "SYS"."M_TABLES" WHERE SCHEMA_NAME = #{schemaName}
</select>
<select id="getTableNameTotal"  resultType="java.lang.Long">SELECT count(TABLE_NAME) FROM "SYS"."M_TABLES"
</select><!-- oracle --><!-- oracle查询schema -->
<select id="getSchemaNameList" resultType="java.lang.String">SELECT owner FROM (SELECT r.*, ROWNUM ROW_ID FROM (SELECT DISTINCT owner FROM ALL_TABLES) r)WHERE ROW_ID &lt;= #{pageSize,jdbcType=DECIMAL}AND ROW_ID >= #{pageNo,jdbcType=DECIMAL}
</select>
<select id="getSchemaNameTotal" resultType="java.lang.Long">SELECT count(DISTINCT owner)FROM ALL_TABLES
</select><!-- oracle查询table-->
<select id="getTableNameList"  resultType="java.lang.String" >SELECT table_name FROM (SELECT r.*, ROWNUM ROW_ID FROM (SELECT table_name  FROM ALL_TABLES WHERE owner = #{schemaName, jdbcType=VARCHAR})r) WHERE ROW_ID &lt;= #{pageSize, jdbcType=DECIMAL} AND ROW_ID >= #{pageNo, jdbcType=DECIMAL}
</select>
<select id="getTableNameTotal"  resultType="java.lang.Long" >SELECT count(table_name)  FROM ALL_TABLES WHERE owner = #{schemaName, jdbcType=VARCHAR}
</select><!-- hana--><!-- hana查询schema-->
<select id="getSchemaNameList"  resultType="java.lang.String">SELECT DISTINCT SCHEMA_NAME FROM "SYS"."M_TABLES"limit #{pageSize,jdbcType=DECIMAL} offset #{pageNo,jdbcType=DECIMAL}
</select>
<select id="getSchemaNameTotal"  resultType="java.lang.Long">SELECT count(DISTINCT SCHEMA_NAME) FROM "SYS"."M_TABLES"
</select><!-- hana查询table-->
<select id="getTableNameList"  resultType="java.lang.String">SELECT TABLE_NAME FROM "SYS"."M_TABLES" WHERE SCHEMA_NAME = #{schemaName, jdbcType=VARCHAR}limit #{pageSize,jdbcType=DECIMAL} offset #{pageNo,jdbcType=DECIMAL}
</select>
<select id="getTableNameTotal"  resultType="java.lang.Long">SELECT count(TABLE_NAME) FROM "SYS"."M_TABLES" WHERE SCHEMA_NAME = #{schemaName}
</select>

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