多数据源配置（Oracle+MySql），拿来即用

前言

        此次配置使用Druid数据源

1、pom文件

<!-- druid -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.9</version>
</dependency>
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.9</version>
</dependency>
<!-- aspect -->
<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
</dependency>
<!-- oracle驱动1 此驱动不需要授权 -->
<dependency>
    <groupId>com.oracle</groupId>
    <artifactId>ojdbc6</artifactId>
    <version>11.2.0.4.0-atlassian-hosted</version>
</dependency>
<!-- oracle驱动2 此驱动需要授权 -->
<!--  <dependency>
          <groupId>com.oracle</groupId>
          <artifactId>ojdbc6</artifactId>
          <version>11.2.0.1.0</version>
      </dependency>  -->

2、application.yml

spring:
  datasource:
    druid:
      first:
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://localhost:3306/liujianming?characterEncoding=utf-8&serverTimezone=Hongkong&useSSL=true&zeroDateTimeBehavior=convertToNull
        username: root
        password: 123456
      second:
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://localhost:3306/test?characterEncoding=utf-8&serverTimezone=Hongkong&useSSL=true&zeroDateTimeBehavior=convertToNull
        username: root
        password: 123456
# Oracle也可以配置
#third:
#  type: com.zaxxer.hikari.HikariDataSource
#  driver-class-name: oracle.jdbc.driver.OracleDriver  # oracle数据源需要pom.xml引入oracle驱动
#  url: #############
#  username: ######
#  password: #####

3、DataSource注解

import java.lang.annotation.*;

/**
 * @author liujianming
 * @version 1.0
 * @describe  1、@Target(ElementType.METHOD): 用于描述方法；
 *            2、@Retention(RetentionPolicy.RUNTIME)：在运行时有效（即运行时保留），编译在class文件中
 *            3、@Documented：将注解包含在javadoc文档中
 * @date 2022/8/24 8:58
 */
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
    String name() default "";
}

4、DataSourceNames接口

/**
 * @author liujianming
 * @version 1.0
 * @describe 配置的数据源名称 配置多少个数据源就写几个
 * @date 2022/8/24 9:03
 */
public interface DataSourceNames {
    String FIRST = "first";
    String SECOND = "second";
}

5、DynamicDataSourceConfig配置类

import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
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 javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

/**
 * @author liujianming
 * @version 1.0
 * @describe
 * @date 2022/8/24 9:04
 */
@Configuration
public class DynamicDataSourceConfig {

    @Bean
    @ConfigurationProperties("spring.datasource.druid.first")
    public DataSource firstDataSource() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties("spring.datasource.druid.second")
    public DataSource secondDataSource() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @Primary
    public DynamicDataSource dataSource(DataSource firstDataSource, DataSource secondDataSource) {
        Map<Object,Object> targetDataSources = new HashMap<>(16);
        targetDataSources.put(DataSourceNames.FIRST,firstDataSource);
        targetDataSources.put(DataSourceNames.SECOND,secondDataSource);
        return new DynamicDataSource(firstDataSource,targetDataSources);
    }
}

6、DynamicDataSource动态数据源

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

import javax.sql.DataSource;
import java.util.Map;

/**
 * @author liujianming
 * @version 1.0
 * @describe 存放DataSource到ThreadLocal中
 * @date 2022/8/24 9:23
 */
public class DynamicDataSource extends AbstractRoutingDataSource {
    private static final ThreadLocal<String> CONTEXT_HOLDER = new ThreadLocal<>();

    public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object,Object> targetDataSources) {
        super.setDefaultTargetDataSource(defaultTargetDataSource);
        super.setTargetDataSources(targetDataSources);
        super.afterPropertiesSet();
    }


    @Override
    protected Object determineCurrentLookupKey() {
        return getDataSource();
    }

    public static void setDataSource(String dataSource) {
        CONTEXT_HOLDER.set(dataSource);
    }

    public static String getDataSource() {
        return CONTEXT_HOLDER.get();
    }

    public static void clearDataSource() {
        CONTEXT_HOLDER.remove();
    }
}

7、DataSourceAspect

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.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.Ordered;
import org.springframework.stereotype.Component;

import java.lang.reflect.Method;

/**
 * @author liujianming
 * @version 1.0
 * @describe 数据源切面扫描
 * @date 2022/8/24 9:32
 */
@Component
@Aspect
public class DataSourceAspect implements Ordered {

    protected Logger logger = LoggerFactory.getLogger(getClass());

    @Pointcut("@annotation(com.ljm.thewaytogod.aspect.dynamic.DataSource)")
    public void dataSourcePointCut() {

    }

    @Around("dataSourcePointCut()")
    public Object around(ProceedingJoinPoint point) throws Throwable {
        MethodSignature signature = (MethodSignature) point.getSignature();
        Method method = signature.getMethod();
        DataSource dataSource = method.getAnnotation(DataSource.class);
        if (dataSource == null) {
            DynamicDataSource.setDataSource(DataSourceNames.FIRST);
        } else {
            DynamicDataSource.setDataSource(dataSource.name());
        }

        try {
            return point.proceed();
        } finally {
            DynamicDataSource.clearDataSource();
        }
    }

    @Override
    public int getOrder() {
        return 1;
    }
}

8、使用

import com.ljm.thewaytogod.aspect.dynamic.DataSource;
import com.ljm.thewaytogod.aspect.dynamic.DataSourceNames;
import com.ljm.thewaytogod.dao.TestMapper;
import com.ljm.thewaytogod.po.SysUser;
import com.ljm.thewaytogod.po.User;
import com.ljm.thewaytogod.service.TestService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

/**
 * @author liujianming
 * @version 1.0
 * @describe
 * @date 2022/8/24 15:48
 */
@Service
public class TestServiceImpl implements TestService {

    @Resource
    private TestMapper testMapper;

    @Override
    @DataSource   // 可以省略，默认是first
    public List<SysUser> selectFromFirst() {
        return testMapper.selectSysUser();
    }

    @Override
    @DataSource(name = DataSourceNames.SECOND)
    public List<User> selectFromSecond() {
        return testMapper.selectUser();
    }
}