springboot，druid动态数据源切换-编程知识

关键字：springboot，druid数据库连接池，两个数据源（可以切换成多个），事务管理

关于druid简介传送门：https://github.com/alibaba/druid/wiki/%E5%B8%B8%E8%A7%81%E9%97%AE%E9%A2%98
在这里插入图片描述

具体分为四步：

1，ThreadLocal维护分支信息，

/*** @ClassName DataSourceContextHolder* @Description: 设置threadlocal数据元信息* @Author gjq* @Date 2024/2/29* @Version V1.0**/
public class DataSourceContextHolder {/**使用Threadlocal维护变量，threadlocal为每个使用该变量的现成提供独立的变量副本，所以每一个线程可以独立的改变自己的副本，而不会影响其他线程使用对应的副本**/private static final ThreadLocal<String> HOLDER = new InheritableThreadLocal<>();public static void setDataSource(String key) {HOLDER.set(key);}public static String getDataSource() {return HOLDER.get();}public static void clearDataSource() {HOLDER.remove();}}

2，创建数据源设置方法，初始化数据源信息

package com.pg.ga.datasource;import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;import javax.sql.DataSource;
import java.util.Map;/*** @ClassName DynamicDataSource* @Description:* @Author gjq* @Date 2024/2/29* @Version V1.0**/
public class DynamicDataSource extends AbstractRoutingDataSource {public DynamicDataSource(DataSource dataSource, Map<Object, Object> targetDataSources) {super.setDefaultTargetDataSource(dataSource);super.setTargetDataSources(targetDataSources);super.afterPropertiesSet();}@Overrideprotected Object determineCurrentLookupKey() {return DataSourceContextHolder.getDataSource();}}

3，多数据源配置，及枚举值定义

枚举值定义：

package com.pg.ga.datasource;public enum DataSourceType {MASTER,SLAVE
}

package com.pg.ga.conf;import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import com.pg.ga.datasource.DataSourceType;
import com.pg.ga.datasource.DynamicDataSource;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;import javax.sql.DataSource;
import java.io.IOException;
import java.util.*;/*** @ClassName PgConfig* @Description:类描述* @Author gjq* @Date 2024/2/29* @Version V1.0**/
@Configuration
@MapperScan({"com.pg.ga.dao"})
public class PgConfig {@Bean@ConfigurationProperties("spring.datasource.druid.master")public DruidDataSource masterDataSource() {return DruidDataSourceBuilder.create().build();}@Bean@ConfigurationProperties("spring.datasource.druid.slave")// @ConditionalOnProperty(prefix = "spring.datasource.druid.slave", name = "enable", havingValue = "true")public DataSource slaveDataSource() {return DruidDataSourceBuilder.create().build();}@Bean(name = "dynamicDataSource")@Primarypublic DynamicDataSource dataSource(DataSource masterDataSource, DataSource slaveDataSource) {Map<Object, Object> targetDataSource = new HashMap<>();targetDataSource.put(DataSourceType.MASTER.name(), masterDataSource);targetDataSource.put(DataSourceType.SLAVE.name(), slaveDataSource);return new DynamicDataSource(masterDataSource(), targetDataSource);}@Beanpublic SqlSessionFactory sqlSessionFactory(DynamicDataSource dynamicDataSource) throws Exception {//核心就是这个，替换原始的SqlSessionFactoryBean 用mybatisSqlSessionFactoryBean即可MybatisSqlSessionFactoryBean factoryBean = new MybatisSqlSessionFactoryBean();factoryBean.setDataSource(dynamicDataSource);//设置mapper.xml位置路径factoryBean.setMapperLocations(resolveMapperLocations());return factoryBean.getObject();}public Resource[] resolveMapperLocations() {ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();List<String> mapperLocations = new ArrayList<>();mapperLocations.add("classpath*:mapper/*.xml");List<Resource> resourceList = new ArrayList<>();if (null != mapperLocations) {for (String mapperLocation : mapperLocations) {try {Resource[] mappers = resourcePatternResolver.getResources(mapperLocation);resourceList.addAll(Arrays.asList(mappers));} catch (IOException e) {e.printStackTrace();}}}return resourceList.toArray(new Resource[resourceList.size()]);}/*** @MethodName:* @Description: 配置@Transactional注解事务* @Param:* @Return:* @Author: gjq* @Date: 2024/2/29**/@Beanpublic PlatformTransactionManager transactionManager(DynamicDataSource dynamicDataSource) {return new DataSourceTransactionManager(dynamicDataSource);}}

4，动态切换注解定义

package com.pg.ga.datasource;import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface DataSource {/**@MethodName:@Description: 切换数据源名称@Param:@Return:@Author: gjq@Date: 2024/2/29**/DataSourceType value() default DataSourceType.MASTER;
}

切面实现

package com.pg.ga.datasource;import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;import java.lang.reflect.Method;/*** @ClassName DataSourceAspect* @Description:类描述* @Author gjq* @Date 2024/2/29* @Version V1.0**/
@Aspect
@Component
@Order(1)
public class DataSourceAspect {//先声明切点@Pointcut("@annotation(com.pg.ga.datasource.DataSource)")public void dsPointCut() {System.out.println(11111);}@Around("dsPointCut()")public Object around(ProceedingJoinPoint point) throws Throwable{MethodSignature signature = (MethodSignature) point.getSignature();Method method = signature.getMethod();DataSource dataSource = method.getAnnotation(DataSource.class);if(null!=dataSource){DataSourceContextHolder.setDataSource(dataSource.value().name());}try{return point.proceed();}finally {DataSourceContextHolder.clearDataSource();}}
}

数据库配置信息.yaml文件配置

server :port : 8090##项目名字配置#servlet :#  context-path : /demotomcat :uri-encoding : UTF-8#xx 报错修改的地方max-connections: 200000max-http-form-post-size: 9000000threads:max: 128min-spare: 5
spring :# 环境 dev|test|prodprofiles :active : dev#引入其他配置文件，例如ftpHX 未配置文件application-ftpHX.yml#include: ftpHX,ftpCloudservlet:multipart:#设置总上传的数据大小max-request-size: 100MB#单个文件大小maxFileSize : 30MB#xx 报错修改的地方max-connections: 200000max-http-post-size: 9000000#热部署模块devtools:restart:#热部署开关enabled: true#指定热部署的目录additional-paths: src/main/java#指定目录不更新exclude: test/**mvc:   #静态文件static-path-pattern : /static/**pathmatch:matching-strategy: ant_path_matcher#模板引擎thymeleaf:model: HTML5prefix: classpath:/templates/suffix: .html#指定编码encoding: utf-8#禁用缓存 默认falsecache: falsejackson:time-zone: GMT+8date-format: yyyy-MM-dd HH:mm:ssredis:ssl: falsedatabase: 0host: 127.0.0.1port: 6379password: timeout: 1000lettuce:pool:max-active: 200max-wait: -1max-idle: 10min-idle: 0# 控制台输出sql、下划线转驼峰
mybatis-plus:mapper-locations: classpath:/mapper/*.xmltypeAliasesPackage: com.pg.ga.model# 控制台输出sql、下划线转驼峰configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImplmap-underscore-to-camel-case: true#pagehelper分页插件
pagehelper:helperDialect: mysqlreasonable: truesupportMethodsArguments: trueparams: count=countSql

application-dev.yaml配置信息

#dev环境  mysql7.0
spring:datasource:type: com.alibaba.druid.pool.DruidDataSourcedriverClassName: org.postgresql.Driver#druid连接池配置druid:#主库数据源master:url: jdbc:postgresql://X.X.X.X:30811/ticketusername: postgrespassword: postgres#备数据源 #关闭slave:enabled: falseurl: jdbc:postgresql://X.X.X.X:30811/ticketusername: postgrespassword: postgres#配置初始化连接数大小initial-size: 10# 最大连接数maxActive: 50#最小连接数minIdle: 10#获取连接等待超时时间maxWait: 5000poolPreparedStatements: 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。maxPoolPreparedStatementPerConnection-size: 20validationQuery: SELECT 1 FROM DUALvalidationQueryTimeout: 20000testOnBorrow: false #申请连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能。testOnReturn: false #归还连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能。testWhileIdle: 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。timeBetweenEvictionRunsMillis: 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minEvictableIdleTimeMillis: 300000  #一个连接在池中最小生存的时间，单位是毫秒maxEvictableIdleTimeMillis: 900000  # 配置一个连接在池中最大生存的时间，单位是毫秒#StatViewServlet配置。（因为暴露的监控信息比较敏感，支持密码加密和访问ip限定）webStatFilter:enabled: truestatViewServlet:enabled: trueurlPattern: /druid/*#可以增加访问账号密码【去掉注释就可以】#login-username: admin#login-password: adminfilter:stat:enabled: true# 慢SQL记录log-slow-sql: trueslow-sql-millis: 1000merge-sql: truewall:config:multi-statement-allow: true

测试controller

package com.pg.ga.controller;import com.alibaba.fastjson.JSONObject;
import com.pg.ga.model.TicketBall;
import com.pg.ga.service.TickService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;@RestController
@RequestMapping("/crud")
public class Crud {@AutowiredTickService tickService;@GetMapping("/master")public String master() {TicketBall ticketBall = tickService.selectMaster();System.out.println(JSONObject.toJSON(ticketBall));return null;}@GetMapping("/slave")public String create() {TicketBall ticketBall = tickService.selectSlave();System.out.println(JSONObject.toJSON(ticketBall));return null;}
}