springboot 动态数据源的实现方法(Mybatis+Druid)

关于Spring Boot动态数据源的实现方法，我将介绍如何使用Mybatis和Druid实现，下面是详细步骤：

1. 引入相关依赖

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.2.6</version>
</dependency>
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.0</version>
</dependency>

2. 添加配置文件

spring:
  datasource:
    dynamic:
      ds1: # 数据源1
        url: jdbc:mysql://localhost:3306/db1?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8
        username: root
        password: root
        driver-class-name: com.mysql.jdbc.Driver
        initial-size: 5
        min-idle: 3
        max-active: 20
        validation-query: SELECT 1
        test-while-idle: true
        time-between-eviction-runs-millis: 60000
      ds2: # 数据源2
        url: jdbc:mysql://localhost:3306/db2?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8
        username: root
        password: root
        driver-class-name: com.mysql.jdbc.Driver
        initial-size: 5
        min-idle: 3
        max-active: 20
        validation-query: SELECT 1
        test-while-idle: true
        time-between-eviction-runs-millis: 60000

3. 创建动态数据源

@Configuration
@EnableTransactionManagement
public class DynamicDataSourceConfig {

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.dynamic")
    public Map<String, DataSource> dataSourceMap() {
        return new LinkedHashMap<>();
    }

    @Bean
    public DataSource dynamicDataSource() {
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        Map<String, DataSource> dataSourceMap = dataSourceMap();
        dynamicDataSource.setTargetDataSources(dataSourceMap);
        dynamicDataSource.setDefaultTargetDataSource(dataSourceMap.get("ds1"));
        return dynamicDataSource;
    }

    @Bean
    public SqlSessionFactory sqlSessionFactory() throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dynamicDataSource());
        return sqlSessionFactoryBean.getObject();
    }

    @Bean
    public DataSourceTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dynamicDataSource());
    }
}

4. 创建动态数据源的工具类

public class DataSourceContextHolder {

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

    public static void setDataSourceType(String dataSourceType) {
        CONTEXT_HOLDER.set(dataSourceType);
    }

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

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

5. 创建数据源切换的AOP拦截器

@Aspect
@Component
public class DataSourceAspect {

    @Pointcut("@annotation(com.example.datasource.annotation.DataSource)")
    public void dataSourcePointcut() {
    }

    @Around("dataSourcePointcut()")
    public Object doAround(ProceedingJoinPoint point) throws Throwable {
        MethodSignature signature = (MethodSignature) point.getSignature();
        DataSource dataSource = signature.getMethod().getAnnotation(DataSource.class);
        if (dataSource != null) {
            DataSourceContextHolder.setDataSourceType(dataSource.value().toString());
        }
        try {
            return point.proceed();
        } finally {
            DataSourceContextHolder.clearDataSourceType();
        }
    }
}

6. 在Service层指定数据源

@Service
public class UserService {

    @Autowired
    private UserMapper userMapper;

    @DataSource(DataSourceEnum.DS2)
    public List<User> getUsers() {
        return userMapper.selectUsers();
    }
}

其中，DataSourceEnum为一个自定义的枚举类，用于枚举不同的数据源。

示例1：添加用户数据到数据源1

在测试类中使用@DataSource(DataSourceEnum.DS1)注解指定数据源1，并执行保存用户数据的操作：

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserServiceTest {

    @Autowired
    private UserService userService;

    @Test
    @DataSource(DataSourceEnum.DS1)
    public void testAddUser() {
        User user = new User();
        user.setUsername("test_user1");
        user.setPassword("test_password1");
        userService.addUser(user);
    }
}

示例2：获取用户数据从数据源2

在测试类中使用@DataSource(DataSourceEnum.DS2)注解指定数据源2，并执行获取用户数据的操作：

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserServiceTest {

    @Autowired
    private UserService userService;

    @Test
    @DataSource(DataSourceEnum.DS2)
    public void testGetUsers() {
        List<User> userList = userService.getUsers();
        Assert.assertEquals(1, userList.size());
    }
}

以上就是Spring Boot动态数据源的实现方法，希望能够帮助到你。