MyBatis动态数据源路由的完整实现教程

// DataSourceContextHolder.java
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();
    }
}

// DynamicDataSource.java
public class DynamicDataSource extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        // 从ThreadLocal中获取当前数据源的key
        return DataSourceContextHolder.getDataSourceType();
    }
}

<!-- Spring XML配置示例 -->
<bean id="masterDataSource" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close">
    <property name="url" value="jdbc:mysql://localhost:3306/master_db" />
    <property name="username" value="root" />
    <property name="password" value="root" />
    <!-- ...其他连接池配置 -->
</bean>

<bean id="slaveDataSource" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close">
    <property name="url" value="jdbc:mysql://localhost:3306/slave_db" />
    <property name="username" value="root" />
    <property name="password" value="root" />
    <!-- ...其他连接池配置 -->
</bean>

<bean id="dynamicDataSource" class="com.example.DynamicDataSource">
    <property name="targetDataSources">
        <map key-type="java.lang.String">
            <entry key="master" value-ref="masterDataSource"/>
            <entry key="slave" value-ref="slaveDataSource"/>
            <!-- 更多数据源可以在这里添加 -->
        </map>
    </property>
    <!-- 默认数据源，当ThreadLocal中没有设置时使用 -->
    <property name="defaultTargetDataSource" ref="masterDataSource"/>
</bean>

<!-- 配置SqlSessionFactory，使用动态数据源 -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="dynamicDataSource"/>
    <!-- ...其他MyBatis配置 -->
</bean>

<!-- 事务管理器也需要使用动态数据源 -->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dynamicDataSource"/>
</bean>

// @TargetDataSource.java
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {
    String value() default "master"; // 默认使用master数据源
}

// DynamicDataSourceAspect.java
@Aspect
@Component
public class DynamicDataSourceAspect {

    // 定义切点，匹配所有带有@TargetDataSource注解的方法
    @Pointcut("@annotation(com.example.annotation.TargetDataSource)")
    public void dataSourcePointCut() {}

    @Around("dataSourcePointCut()")
    public Object around(ProceedingJoinPoint point) throws Throwable {
        MethodSignature signature = (MethodSignature) point.getSignature();
        Method method = signature.getMethod();

        TargetDataSource targetDataSource = method.getAnnotation(TargetDataSource.class);
        if (targetDataSource == null) {
            // 如果方法上没有注解，尝试获取类上的注解
            targetDataSource = method.getDeclaringClass().getAnnotation(TargetDataSource.class);
        }

        if (targetDataSource != null) {
            String dataSourceType = targetDataSource.value();
            DataSourceContextHolder.setDataSourceType(dataSourceType);
            System.out.println("切换到数据源: " + dataSourceType); // 调试信息
        }

        try {
            return point.proceed(); // 执行目标方法
        } finally {
            // 确保在方法执行完成后清除ThreadLocal，避免内存泄漏或数据源混乱
            DataSourceContextHolder.clearDataSourceType();
            System.out.println("数据源已清除"); // 调试信息
        }
    }
}

<!-- 启用Spring AOP注解 -->
<aop:aspectj-autoproxy proxy-target-class="true"/>