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SpringBoot2(四)：多数据源自动切换

SpringBoot2(四)：多数据源自动切换

作者: 帅气滴糟老头 | 来源:发表于2019-01-04 17:13 被阅读0次

类似的实现百度一大把，不过别人实现了的照搬到自己电脑上不见的也可以运行，依然遇到很多问题，这回自己实现一把，亲测可用，文末附源码地址。

核心配置代码：

1. pom

<?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>
        <!-- 分页插件 -->
        <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代码-->
        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>1.3.5</version>
        </dependency>
        <!-- alibaba的druid数据库连接池 -->
        <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>
                    <!--允许移动生成的文件-->
                    <verbose>true</verbose>
                    <!--允许覆盖生成的文件-->
                    <overwrite>true</overwrite>
                    <!--配置文件的路径 默认resources目录下-->
                    <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
                </configuration>
                <!--插件依赖的jar包-->
                <dependencies>
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>8.0.13</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>

    </build>
</project>

2. application.yml

注意：springboot2开始mysql驱动变为com.mysql.cj.jdbc.Driver

server:
  port: 8080

spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    primary:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/test?useSSL=false&useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedStatements=TRUE&serverTimezone=UTC&allowMultiQueries=true
      username: root
      password: root
      type: com.alibaba.druid.pool.DruidDataSource
      #druid相关配置
      druid:
        #监控统计拦截的filters
        filters: stat
        #配置初始化大小/最小/最大
        initial-size: 1
        min-idle: 1
        max-active: 20
        #获取连接等待超时时间
        max-wait: 60000
        #间隔多久进行一次检测，检测需要关闭的空闲连接
        time-between-eviction-runs-millis: 60000
        #一个连接在池中最小生存的时间
        min-evictable-idle-time-millis: 300000
        validation-query: SELECT 'x'
        test-while-idle: true
        test-on-borrow: false
        test-on-return: false
        #打开PSCache，并指定每个连接上PSCache的大小。oracle设为true，mysql设为false。分库分表较多推荐设置为false
        pool-prepared-statements: false
        max-pool-prepared-statement-per-connection-size: 20
    local:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/test2?useSSL=false&useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedStatements=TRUE&serverTimezone=UTC&allowMultiQueries=true
      username: root
      password: root
      type: com.alibaba.druid.pool.DruidDataSource
    prod:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/test3?useSSL=false&useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedStatements=TRUE&serverTimezone=UTC&allowMultiQueries=true
      username: root
      password: root
      type: com.alibaba.druid.pool.DruidDataSource

mybatis:
  #映射文件所在路径
  mapper-locations: classpath:com.along.dao/*.xml
  #pojo类所在包路径
  type-aliases-package: com.along.entity
  configuration:
    #配置项：开启下划线到驼峰的自动转换. 作用：将数据库字段根据驼峰规则自动注入到对象属性。
    map-underscore-to-camel-case: true

#pagehelper
pagehelper:
  helperDialect: mysql
  reasonable: true
  supportMethodsArguments: true
  params: count=countSql

logging:
  level:
    #打印SQL信息
    com.along.dao: debug

3. 数据源配置类 MultipleDataSourceConfig.java

/**
 * 数据源配置
 */
@Configuration
public class MultipleDataSourceConfig {

    @Bean(name = "dataSourcePrimary")
    @ConfigurationProperties(prefix = "spring.datasource.primary")
    public DataSource primaryDataSource() {
        return new DruidDataSource();
    }

    @Bean(name = "dataSourceLocal")
    @ConfigurationProperties(prefix = "spring.datasource.local")
    public DataSource localDataSource() {
        return new DruidDataSource();
    }

    @Bean(name = "dataSourceProd")
    @ConfigurationProperties(prefix = "spring.datasource.prod")
    public DataSource prodDataSource() {
        return new DruidDataSource();
    }

    @Primary
    @Bean(name = "dynamicDataSource")
    public DataSource dynamicDataSource() {
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        //配置默认数据源
        dynamicDataSource.setDefaultTargetDataSource(primaryDataSource());

        //配置多数据源
        HashMap<Object, Object> dataSourceMap = new HashMap<>();
        dataSourceMap.put(ContextConst.DataSourceType.PRIMARY.name(), primaryDataSource());
        dataSourceMap.put(ContextConst.DataSourceType.LOCAL.name(), localDataSource());
        dataSourceMap.put(ContextConst.DataSourceType.PROD.name(), prodDataSource());
        dynamicDataSource.setTargetDataSources(dataSourceMap); // 该方法是AbstractRoutingDataSource的方法
        return dynamicDataSource;
    }

    /**
     * 配置@Transactional注解事务
     *
     * @return
     */
    @Bean
    public PlatformTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dynamicDataSource());
    }
}

4. 数据源持有类 DataSourceContextHolder.java

/**
 * 数据源持有类
 */
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("切换到[{}]数据源",dbType);
        contextHolder.set(dbType);
    }

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

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

5. 数据源路由实现类 DynamicDataSource.java

/**
 * 数据源路由实现类
 */
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("当前数据源为[primary]");
        } else {
            logger.info("当前数据源为{}", dataSource);
        }
        return dataSource;
    }

}

6. 自定义切换数据源的注解

/**
 * 切换数据源的注解
 */
@Target({ElementType.TYPE,ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {

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

}

7. 数据源枚举类

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

    /**
     * 数据源枚举
     */
    enum DataSourceType {
        PRIMARY, LOCAL, PROD, TEST
    }
}

8. 定义切换数据源的切面，为注解服务

/**
 * 切换数据源的切面
 */
@Component
@Aspect
@Order(1) //这是关键，要让该切面调用先于AbstractRoutingDataSource的determineCurrentLookupKey()
public class DynamicDataSourceAspect {

    @Before("execution(* com.along.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.along.service..*.*(..))")
    public void after(JoinPoint point) {
        DataSourceContextHolder.clearDataSource();
    }
}

9. 修改启动类

//排除DataSource自动配置类,否则会默认自动配置,不会使用我们自定义的DataSource,并且启动报错
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@MapperScan({"com.along.dao"}) // 扫描包路径
public class SpringBootMybatisMultipleDatasourceApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootMybatisMultipleDatasourceApplication.class, args);
    }

}

10. 使用

在方法上通过注解@DataSource指定该方法所用的数据源，如果没有使用注解指定则使用默认数据源
下面是在service实现类中的应用：

/**
 * @Description: service实现
 * @Author along
 * @Date 2018/12/28 17:44
 */
@Service(value = "personService")
@Transactional
public class PersonServiceImpl implements PersonService {

    private PersonMapper personMapper;

    @Autowired
    public PersonServiceImpl(@Qualifier("personMapper") PersonMapper personMapper) {
        this.personMapper = personMapper;
    }

    @Override
    public Integer add(Person person) {
        return personMapper.insert(person);
    }

    @Override
    public PageInfo<Person> findAllPerson(int pageNum, int pageSize) {
        PageHelper.startPage(pageNum, pageSize);
        PersonExample example = new PersonExample();
        List<Person> personList = personMapper.selectByExample(example);
        return new PageInfo<>(personList);
    }

    @DataSource(ContextConst.DataSourceType.PROD) // 指定该方法使用prod数据源
    @Override
    public PageInfo<Person> findByName(String name) {
        PersonExample example = new PersonExample();
        PersonExample.Criteria criteria = example.createCriteria();
        criteria.andNameEqualTo(name);
        List<Person> personList = personMapper.selectByExample(example);
        return new PageInfo<>(personList);
    }

    @DataSource(ContextConst.DataSourceType.LOCAL) // 指定该方法使用local数据源
    @Override
    public int insert(Person person) {

        return personMapper.insert(person);
    }

    @Override
    public int insertBatch(List<Person> list) {
        return personMapper.insertBatchSelective(list);
    }

    @Override
    public int updateBatch(List<Person> list) {
        return personMapper.updateBatchByPrimaryKeySelective(list);

    }

}

源码地址

https://github.com/alonglong/spring-boot-all/tree/master/spring-boot-mybatis-multiple-datasource

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