SpringBoot从数据库读取数据数据源配置信息，动态切换数据源

准备多个数据库

首先准备多个数据库，主库smiling-datasource，其它库test1、test2、test3

接下来，我们在主库smiling-datasource中，创建表databasesource，用于存储多数据源相关信息。表结构设计如下

创建好表之后，向表databasesource中存储test1、test2、test3三个数据库的相关配置信息

在主库的表databasesource中存储好数据源信息后，接下来分别在test1、test2、test3以及主库smiling-datasource中都创建sys_user数据表，用于后续测试数据源切换是否正常。sys_user的表结构如下所示

创建好sys_user之后，分别向sys_user表中添加一条数据，添加的数据中分表用不同的内容表示属于哪个库，方便后续测试。

依赖

该实现主要用到JDK1.8、spring-boot-starter-parent的版本为2.2.0.RELEASE，除此之外需要用到mysql、druid以及mybatis-plus的依赖

配置

在配置文件application.yml中主要配置主库的数据源信息，配置如下

spring:aop:proxy-target-class: true   #true为使用CGLIB代理datasource:url: jdbc:mysql://localhost:3306/smiling-datasource?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8&zeroDateTimeBehavior=convertToNullusername: rootpassword: zhangpei@123driver-class-name: com.mysql.cj.jdbc.Drivertype: com.alibaba.druid.pool.DruidDataSourcedruid:initial-size: 5 #初始化大小min-idle: 5 #最小连接数max-active: 20  #最大连接数time-between-eviction-runs-millis: 60000  #配置间隔多久进行一次检测，检测需要关闭的空闲连接,单位毫秒min-evictable-idle-time-millis: 300000  #配置一个连接在池中最小生存的时间，单位毫秒validation-query: SELECT 1 FROM DUALtest-while-idle: truetest-on-borrow: falsetest-on-return: falsepool-prepared-statements: truemax-pool-prepared-statement-per-connection-size: 20filters: stat,wall,log4j  #配置监控统计拦截的filters，去掉后监控界面sql无法统计，wall用于防火墙connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000 #通过该属性打开mergeSQl功能：慢sql记录功能use-global-data-source-stat: true #合并多个DruidDataSource的监控数据max-wait: 60000 #配置获取连接等待超时时间
mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImplmapper-locations: classpath*:/mapping/*.xml

基类DataSource

创建类DataSource，用于数据源信息的装配

@Data
@ToString
public class DataSource {String datasourceId;String url;String username;String password;String code;String databasetype;String driverclass;String key;}

DruidDBConfig配置类

该配置类主要用于配置默认的主数据源信息，配置Druid数据库连接池，配置sql工厂加载mybatis的文件，扫描实体类等

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
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;
import javax.sql.DataSource;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;/*** 配置默认数据源* 配置Druid数据库连接池* 配置sql工厂加载mybatis的文件，扫描实体等** @author smiling* @date 2023/10/7 19:04*/
@Slf4j
@Configuration
@EnableTransactionManagement
public class DruilDBConfig {@Value("${spring.datasource.url}")private String dbUrl;@Value("${spring.datasource.username}")private String username;@Value("${spring.datasource.password}")private String password;@Value("${spring.datasource.driver-class-name}")private String driverClassName;// 连接池连接信息@Value("${spring.datasource.druid.initial-size}")private int initialSize;@Value("${spring.datasource.druid.min-idle}")private int minIdle;@Value("${spring.datasource.druid.max-active}")private int maxActive;@Value("${spring.datasource.druid.max-wait}")private int maxWait;@Bean@Primary@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);dataSource.setPoolPreparedStatements(true); //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.setMaxPoolPreparedStatementPerConnectionSize(20);//  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");//对于耗时长的查询sql，会受限于ReadTimeout的控制，单位毫秒dataSource.setTestOnBorrow(true); //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.setTestWhileIdle(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。String validationQuery = "select 1 from dual";dataSource.setValidationQuery(validationQuery); //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.setFilters("stat,wall");//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.setTimeBetweenEvictionRunsMillis(60000); //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.setMinEvictableIdleTimeMillis(180000); //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.setKeepAlive(true); //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.setRemoveAbandoned(true); //是否移除泄露的连接/超过时间限制是否回收。dataSource.setRemoveAbandonedTimeout(3600); //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.setLogAbandoned(true); //移除泄露连接发生是是否记录日志return dataSource;}/*** 注册一个statViewServlet druid监控页面配置* 账号密码配置** @return*/@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();// Resource mybatisConfigXml = resolver.getResource("classpath:mybatis/mybatis-config.xml");//  sqlSessionFactoryBean.setConfigLocation(mybatisConfigXml);// 设置别名包//  sqlSessionFactoryBean.setTypeAliasesPackage("com.testdb.dbsource.pojo");//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:/mapping/*.xml"));return sqlSessionFactoryBean.getObject();}/*** 读取驼峰命名设置** @return*/@Bean@ConfigurationProperties(prefix = "mybatis-plus.configuration")public org.apache.ibatis.session.Configuration configuration() {return new org.apache.ibatis.session.Configuration();}}

DBContextHolder类

该类主要用于手动切换数据源

import lombok.extern.slf4j.Slf4j;/*** @author smiling* @date 2023/10/7 19:16*/
@Slf4j
public class DBContextHolder {//对当前线程的操作-线程安全的private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();//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");}}

DynamicDataSource类

该类实现手动加载默认数据源、创建数据源连接、检查数据源连接、删除数据源连接等

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.stat.DruidDataSourceStatManager;
import com.smiling.datasource.model.DataSource;
import lombok.extern.slf4j.Slf4j;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import org.springframework.util.ObjectUtils;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Map;
import java.util.Set;/*** 手动加载默认数据源* 创建数据源连接* 检查数据源连接* 删除数据源连接等** @author smiling* @date 2023/10/8 11:03*/
@Slf4j
public class DynamicDataSource extends AbstractRoutingDataSource {private boolean debug = true;private Map<Object, Object> dynamicTargetDataSources;private Object dynamicDefaultTargetDataSource;@Overrideprotected Object determineCurrentLookupKey() {String datasource = DBContextHolder.getDataSource();if (!ObjectUtils.isEmpty(datasource)) {Map<Object, Object> targetDataSource = this.dynamicTargetDataSources;if (targetDataSource.containsKey(datasource)) {log.info("当前数据源:" + datasource);} else {log.info("不存在的数据源");return null;}} 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 {try {Class.forName(driveClass);DriverManager.getConnection(url, username, password);} catch (Exception e) {return false;}@SuppressWarnings("resource")DruidDataSource druidDataSource = new DruidDataSource();druidDataSource.setName(key);druidDataSource.setDriverClassName(driveClass);druidDataSource.setUrl(url);druidDataSource.setUsername(username);druidDataSource.setPassword(password);druidDataSource.setInitialSize(1); //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.setMaxActive(20); //最大连接池数量druidDataSource.setMaxWait(60000); //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.setMinIdle(5); //最小连接池数量String validationQuery = "select 1 from dual";druidDataSource.setTestOnBorrow(true); //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.setTestWhileIdle(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.setValidationQuery(validationQuery); //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.setFilters("stat");//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.setTimeBetweenEvictionRunsMillis(60000); //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.setMinEvictableIdleTimeMillis(180000); //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.setKeepAlive(true); //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.setRemoveAbandoned(true); //是否移除泄露的连接/超过时间限制是否回收。druidDataSource.setRemoveAbandonedTimeout(3600); //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.setLogAbandoned(true); //移除泄露连接发生是是否记录日志druidDataSource.init();this.dynamicTargetDataSources.put(key, druidDataSource);setTargetDataSources(this.dynamicTargetDataSources);// 将map赋值给父类的TargetDataSourcessuper.afterPropertiesSet();// 将TargetDataSources中的连接信息放入resolvedDataSources管理log.info(key + "数据源初始化成功");return true;} catch (Exception e) {log.error(e + "");return false;}}//删除数据源public boolean delDatasources(String datasourceid) {Map<Object, Object> targetDataSource = this.dynamicTargetDataSources;if (targetDataSource.containsKey(datasourceid)) {Set<DruidDataSource> druidDataSourceInstances = DruidDataSourceStatManager.getDruidDataSourceInstances();for (DruidDataSource source : druidDataSourceInstances) {if (datasourceid.equals(source.getName())) {targetDataSource.remove(datasourceid);DruidDataSourceStatManager.removeDataSource(source);setTargetDataSources(targetDataSource);// 将map赋值给父类的TargetDataSourcessuper.afterPropertiesSet();// 将TargetDataSources中的连接信息放入resolvedDataSources管理return true;}}return false;} else {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;}public void setDebug(boolean debug) {this.debug = debug;}public boolean isDebug() {return debug;}public Map<Object, Object> getDynamicTargetDataSources() {return dynamicTargetDataSources;}public void setDynamicTargetDataSources(Map<Object, Object> dynamicTargetDataSources) {this.dynamicTargetDataSources = dynamicTargetDataSources;}public Object getDynamicDefaultTargetDataSource() {return dynamicDefaultTargetDataSource;}public void setDynamicDefaultTargetDataSource(Object dynamicDefaultTargetDataSource) {this.dynamicDefaultTargetDataSource = dynamicDefaultTargetDataSource;}public void createDataSourceWithCheck(DataSource dataSource) throws Exception {String datasourceId = dataSource.getDatasourceId();log.info("正在检查数据源：" + datasourceId);Map<Object, Object> targetDataSources = this.dynamicTargetDataSources;if (targetDataSources.containsKey(datasourceId)) {log.info("数据源" + datasourceId + "之前已经创建，准备测试数据源是否正常...");//DataSource druidDataSource = (DataSource) dynamicTargetDataSources2.get(datasourceId);DruidDataSource druidDataSource = (DruidDataSource) targetDataSources.get(datasourceId);boolean rightFlag = true;Connection connection = null;try {log.info(datasourceId + "数据源的概况->当前闲置连接数：" + druidDataSource.getPoolingCount());long activeCount = druidDataSource.getActiveCount();log.info(datasourceId + "数据源的概况->当前活动连接数：" + activeCount);if (activeCount > 0) {log.info(datasourceId + "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" + datasourceId + "正常");} catch (Exception e) {log.error(e.getMessage(), e); //把异常信息打印到日志文件rightFlag = false;log.info("缓存数据源" + datasourceId + "已失效，准备删除...");if (delDatasources(datasourceId)) {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);}}private void createDataSource(DataSource dataSource) throws Exception {String datasourceId = dataSource.getDatasourceId();log.info("准备创建数据源" + datasourceId);String databasetype = dataSource.getDatabasetype();String username = dataSource.getUsername();String password = dataSource.getPassword();String url = dataSource.getUrl();String driveClass = "com.mysql.cj.jdbc.Driver";if (testDatasource(datasourceId, driveClass, url, username, password)) {boolean result = this.createDataSource(datasourceId, driveClass, url, username, password, databasetype);if (!result) {log.error("数据源" + datasourceId + "配置正确，但是创建失败");}} else {log.error("数据源配置有错误");}}}

切换数据源使用的方法

首先获取主数据源的表databasesource里面的所有西悉尼，然后根据我们传入对应的数据源id进行数据源的切换

DataSourceMapper

@Mapper
public interface DataSourceMapper {@Select("select * from databasesource")List<DataSource> get();    }

DBChangeService

public interface DBChangeService {List<DataSource> get();boolean changeDb(String datasourceId) throws Exception;}

DBChangeServiceImpl

@Service
public class DBChangeServiceImpl implements DBChangeService {private DataSourceMapper dataSourceMapper;private DynamicDataSource dynamicDataSource;public DBChangeServiceImpl(DataSourceMapper dataSourceMapper,DynamicDataSource dynamicDataSource){this.dataSourceMapper = dataSourceMapper;this.dynamicDataSource = dynamicDataSource;}    @Overridepublic List<DataSource> get() { return dataSourceMapper.get(); }@Overridepublic boolean changeDb(String datasourceId) throws Exception {//默认切换到主数据源，进行整体资源的查找DBContextHolder.clearDataSource();List<DataSource> dataSourceList = dataSourceMapper.get();for(DataSource source : dataSourceList){if(source.getDatasourceId().equals(datasourceId)){System.out.println("需要使用的数据源已经找到，datasourceId是："+source.getDatasourceId());//创建数据源连接&检查，若存在则不需要重新创建dynamicDataSource.createDataSourceWithCheck(source);//切换到该数据源DBContextHolder.setDataSource(source.getDatasourceId());return true;}}return false;}}