Springboot整合Mybatis實現多數據源動態切換

                     Springboot整合Mybatis實現多數據源動態切換

 

1 業務背景

最近一個項目中需要在oracle數據庫中讀取用戶信息，需要在mysql中讀取業務數據。

2 解決方案

• 多數據源配置

在比較大型的項目中，數據庫可能會分佈在多臺服務器上，例如有若干個數據庫服務是專門存放日誌數據的，又有若干個數據庫服務是專門存放業務數據、讀寫分離的等等....這時候應用程序如果需要對這兩種類型的數據進行處理的話，就需要配置多數據源了。

• 微服務化

在如今微服務大行其道的今天，沒有啥是爲服務解決不了的，既然需要在不同的數據庫讀取信息，那麼我們就可以將業務拆分爲二，獨立一個服務出來專門負責oracle數據庫的連接查詢，獨立一個服務負責mysql數據庫的業務處理。再新建一個工程調用這兩個服務問題就迎刃而解。

由於該項目是存在已久的老項目，目前不具備微服務化得能力而且時間也不允許。因此只能退而求其次在項目中引進多數據源。

達到按照需求動態切換的目的。

 

3  具體實現

    pom文件配置

    

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <artifactId>spring-boot-mybatis-multiple-datasource</artifactId>
    <packaging>jar</packaging>

    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot-mybatis-multiple-datasource</name>
    <description>Demo Multiple Datasource for Spring Boot</description>

    <parent>
        <groupId>com.along</groupId>
        <artifactId>spring-boot-all</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>
        <!-- 分頁插件 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.10</version>
        </dependency>
        <!-- mybatis-generator-core 反向生成java代碼-->
        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>1.3.5</version>
        </dependency>
        <!-- alibaba的druid數據庫連接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <!--mybatis逆向工程maven插件-->
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.5</version>
                <configuration>
                    <!--允許移動生成的文件-->
                    <verbose>true</verbose>
                    <!--允許覆蓋生成的文件-->
                    <overwrite>true</overwrite>
                    <!--配置文件的路徑 默認resources目錄下-->
                    <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
                </configuration>
                <!--插件依賴的jar包-->
                <dependencies>
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>8.0.13</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>

    </build>
</project>

   application.properties文件

   

spring.application.name=springboot-datasource
server.port=8081



## mysql database
spring.datasource.local.url=****
spring.datasource.local.username=****
spring.datasource.local.password=****
spring.datasource.local.driver-class-name=com.mysql.jdbc.Driver
## oracle database
spring.datasource.oracle.url=****
spring.datasource.oracle.username=****
spring.datasource.oracle.password****
spring.datasource.oracle.driver-class-name=****

  實際配置以實際爲準，以上僅供參考：

• 基於分包方式實現

       配置mysql數據庫的datasource

      

package com.lb.api.config;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
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.support.PathMatchingResourcePatternResolver;

@Configuration
//開啓事務管理
@MapperScan(basePackages = "com.lb.api.dao.local", sqlSessionFactoryRef = "test1SqlSessionFactory")
public class LocalDataSourceConfig  {

  //這裏必須要要加 @Qualifier(value = "localDatasource")註解
  //否則Spring將不會知道用哪個Bean
	 @Bean(name = "localDatasource")
	    @Qualifier(value = "localDatasource")
	    @ConfigurationProperties(prefix = "spring.datasource.local")
	    public DataSource localDatasource() {
	        return DataSourceBuilder.create().build();
	    }

  @Bean(name = "test1SqlSessionFactory")
  // 表示這個數據源是默認數據源
  @Primary
  // @Qualifier表示查找Spring容器中名字爲test1DataSource的對象
  public SqlSessionFactory test1SqlSessionFactory(@Qualifier("localDatasource") DataSource datasource)
          throws Exception {
      SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
      bean.setDataSource(datasource);
      bean.setMapperLocations(
              // 設置mybatis的xml所在位置
              new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/test01/*.xml"));
      return bean.getObject();
  }
  @Bean("test1SqlSessionTemplate")
  // 表示這個數據源是默認數據源
  @Primary
  public SqlSessionTemplate test1sqlsessiontemplate(
          @Qualifier("test1SqlSessionFactory") SqlSessionFactory sessionfactory) {
      return new SqlSessionTemplate(sessionfactory);
  }

}

 1:@MapperScan(basePackages = "com.lb.api.dao.local", sqlSessionFactoryRef = "test1SqlSessionFactory")

其中basePackages配置是你需要連接mysql數據庫的mapper文件存放的路徑。

 2：@ConfigurationProperties(prefix = "spring.datasource.local")

prefix 配置讀取以local開頭的數據庫配置屬性

3：@Primary一定要加，並且只能加在一個datasource上，因爲它代表默認配置，加在你需要設置的默認datasource上。

4:    new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/test02/*.xml"));

配置你需要掃描的mapper.xml文件的路徑，記得不同數據源需要區分開來。

 

 配置oracle數據庫的datasource

  

package com.lb.api.config;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
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.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.TransactionManagementConfigurer;

@Configuration
//配置mybatis的接口類放的地方
@MapperScan(basePackages = "com.lb.api.dao.oracle", sqlSessionFactoryRef = "test2SqlSessionFactory")
public class OracleDatasourceConfig {
	
	
	 @Bean(name = "oracleDatasource")
	    @Qualifier(value = "oracleDatasource")
	    @ConfigurationProperties(prefix = "spring.datasource.oracle")
	    public DataSource oracleDatasource() {
	        return DataSourceBuilder.create().build();
	    }

	    @Bean(name = "test2SqlSessionFactory")
	    // 表示這個數據源是默認數據源
	    // @Qualifier表示查找Spring容器中名字爲test1DataSource的對象
	    public SqlSessionFactory test1SqlSessionFactory(@Qualifier("oracleDatasource") DataSource datasource)
	            throws Exception {
	        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
	        bean.setDataSource(datasource);
	        bean.setMapperLocations(
	                // 設置mybatis的xml所在位置
	                new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/test02/*.xml"));
	        return bean.getObject();
	    }
	    @Bean("test2SqlSessionTemplate")
	    // 表示這個數據源是默認數據源
	    public SqlSessionTemplate test1sqlsessiontemplate(
	            @Qualifier("test2SqlSessionFactory") SqlSessionFactory sessionfactory) {
	        return new SqlSessionTemplate(sessionfactory);
	    }


}

至此一個雙數據源的服務就搭建好了，當你調用相應mapper文件裏的數據庫操作時會調用不同的數據庫。 

• 基於AOP方式的動態切換

 

1. 數據源配置類 MultipleDataSourceConfig.java

package com.lb.api.config;

import java.util.HashMap;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
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.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

@Configuration
public class DataSourceConfig {
	
	    @Bean(name = "localDatasource")
	    @Qualifier(value = "localDatasource")
	    @ConfigurationProperties(prefix = "spring.datasource.local")
	    public DataSource localDatasource() {
	        return DataSourceBuilder.create().build();
	    }

	    @Bean(name = "oracleDatasource")
	    @Qualifier(value = "oracleDatasource")
	    @ConfigurationProperties(prefix = "spring.datasource.oracle")
	    public DataSource oracleDatasource() {
	        return DataSourceBuilder.create().build();
	    }
	    
	    @Bean(name = "sqlSessionFactory")
	    // 表示這個數據源是默認數據源
	    // @Qualifier表示查找Spring容器中名字爲test1DataSource的對象
	    public SqlSessionFactory sqlSessionFactory()
	            throws Exception {
	        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
	        bean.setDataSource(dynamicDataSource());
	        bean.setMapperLocations(
	                // 設置mybatis的xml所在位置
	                new PathMatchingResourcePatternResolver().getResources("classpath*:mapper/*.xml"));
	        return bean.getObject();
	    }
	    @Bean("sqlSessionTemplate")
	    // 表示這個數據源是默認數據源
	    public SqlSessionTemplate sqlsessiontemplate(
	            @Qualifier("sqlSessionFactory") SqlSessionFactory sessionfactory) {
	        return new SqlSessionTemplate(sessionfactory);
	    }
	    
	    @Primary
	    @Bean(name = "dynamicDataSource")
	    public DataSource dynamicDataSource() {
	        DynamicDataSource dynamicDataSource = new DynamicDataSource();
	        //配置默認數據源
	        dynamicDataSource.setDefaultTargetDataSource(localDatasource());
	        //配置多數據源
	        HashMap<Object, Object> dataSourceMap = new HashMap<>();
	        dataSourceMap.put(ContextConst.DataSourceType.PRIMARY.name(), oracleDatasource());
	        dataSourceMap.put(ContextConst.DataSourceType.LOCAL.name(), localDatasource());
	        dynamicDataSource.setTargetDataSources(dataSourceMap); // 該方法是AbstractRoutingDataSource的方法
	        return dynamicDataSource;
	    }
	    
	    @Bean
	    public PlatformTransactionManager bfTransactionManager() {
	     return new DataSourceTransactionManager(dynamicDataSource());
	    }
	     
//	    @Bean
//	    public PlatformTransactionManager bfscrmTransactionManager(@Qualifier("oracleDatasource")DataSource oracleDatasource) {
//	     return new DataSourceTransactionManager(oracleDatasource);
//	    }

}

2. 數據源持有類 DataSourceContextHolder.java

/**
 * 數據源持有類
 */
public class DataSourceContextHolder {

    private static final Logger logger = LoggerFactory.getLogger(DataSourceContextHolder.class);

    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();

    public static void setDataSource(String dbType){
        logger.info("切換到[{}]數據源",dbType);
        contextHolder.set(dbType);
    }

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

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

3. 數據源路由實現類 DynamicDataSource.java

/**
 * 數據源路由實現類
 */
public class DynamicDataSource extends AbstractRoutingDataSource {

    private static final Logger logger = LoggerFactory.getLogger(DynamicDataSource.class);

    @Override
    protected Object determineCurrentLookupKey() {
        String dataSource = DataSourceContextHolder.getDataSource();
        if (dataSource == null) {
            logger.info("當前數據源爲[primary]");
        } else {
            logger.info("當前數據源爲{}", dataSource);
        }
        return dataSource;
    }

}

4. 自定義切換數據源的註解

/**
 * 切換數據源的註解
 */
@Target({ElementType.TYPE,ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {

    ContextConst.DataSourceType value() default ContextConst.DataSourceType.PRIMARY;

}

5. 數據源枚舉類

/**
 * 上下文常量
 */
public interface ContextConst {

    /**
     * 數據源枚舉
     */
    enum DataSourceType {
        PRIMARY, LOCAL, PROD, TEST
    }
}

6. 定義切換數據源的切面，爲註解服務

package com.lb.api.config;

import java.lang.reflect.Method;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

/**
 * 切換數據源的切面
 */
@Component
@Aspect
@Order(1) //這是關鍵，要讓該切面調用先於AbstractRoutingDataSource的determineCurrentLookupKey()
public class DynamicDataSourceAspect {

    @Before("execution(* com.lb.api.service..*.*(..))")
    public void before(JoinPoint point) {
        try {
            DataSource annotationOfClass = point.getTarget().getClass().getAnnotation(DataSource.class);
            String methodName = point.getSignature().getName();
            Class[] parameterTypes = ((MethodSignature) point.getSignature()).getParameterTypes();
            Method method = point.getTarget().getClass().getMethod(methodName, parameterTypes);
            DataSource methodAnnotation = method.getAnnotation(DataSource.class);
            methodAnnotation = methodAnnotation == null ? annotationOfClass : methodAnnotation;
            ContextConst.DataSourceType dataSourceType = methodAnnotation != null
                    && methodAnnotation.value() != null ? methodAnnotation.value() : ContextConst.DataSourceType.PRIMARY;

            DataSourceContextHolder.setDataSource(dataSourceType.name());
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        }
    }

    @After("execution(* com.lb.api.service..*.*(..))")
    public void after(JoinPoint point) {
        DataSourceContextHolder.clearDataSource();
    }
}

7. 修改啓動類

package com.lb.api;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.lb.api.service.DataSourceService;

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@MapperScan(basePackages = "com.lb.api.dao")
@RestController
public class ApiApplication {

	public static void main(String[] args) {
		SpringApplication.run(ApiApplication.class, args);
	}
	
	@Autowired
	private DataSourceService dataSourceService;
	
	
	@RequestMapping(value="/test")
	
	public void test(){
		dataSourceService.test01();
		dataSourceService.test02();
	}
	
	
}

8 使用

在方法上通過註解@DataSource指定該方法所用的數據源，如果沒有使用註解指定則使用默認數據源
下面是在service實現類中的應用：

package com.lb.api.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.lb.api.config.ContextConst;
import com.lb.api.config.DataSource;
import com.lb.api.dao.LivesubscriptionMapper;
import com.lb.api.dao.TOperHisMapper;
@Service
public class DataSourceService {
	
	@Autowired
	private LivesubscriptionMapper livesubscriptionMapper;
	
	@Autowired
	private TOperHisMapper tOperHisMapper;
	
	  @DataSource(ContextConst.DataSourceType.LOCAL) // 指定該方法使用prod數據源
	  public void test01() {
		  System.out.println(livesubscriptionMapper.selectByExample().size());
	  }
	  
	  @DataSource(ContextConst.DataSourceType.PRIMARY) // 指定該方法使用prod數據源
	  public void test02() {
		  System.out.println(tOperHisMapper.selectByExample().size());
	  }
	

}

訪問鏈接localhost:8081/test

2019-10-09 16:36:35.777  INFO 14752 --- [nio-8081-exec-7] c.lb.api.config.DataSourceContextHolder  : 切換到[LOCAL]數據源
2019-10-09 16:36:35.785  INFO 14752 --- [nio-8081-exec-7] com.lb.api.config.DynamicDataSource      : 當前數據源爲LOCAL
83
2019-10-09 16:36:35.838  INFO 14752 --- [nio-8081-exec-7] c.lb.api.config.DataSourceContextHolder  : 切換到[PRIMARY]數據源
2019-10-09 16:36:35.838  INFO 14752 --- [nio-8081-exec-7] com.lb.api.config.DynamicDataSource      : 當前數據源爲PRIMARY
0

達到了動態切換的目的。