Spring通过拦截器实现多数据源切换的示例代码

@Configuration
public class DataSourceConfig {

    @Bean(name = "primaryDataSource")
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource.primary")
    public DataSource primaryDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "secondaryDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.secondary")
    public DataSource secondaryDataSource() {
        return DataSourceBuilder.create().build();
    }
}

public class DynamicDataSource extends AbstractRoutingDataSource {

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

    @Override
    protected Object determineCurrentLookupKey() {
        return contextHolder.get();
    }

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

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

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

@Configuration
public class DynamicDataSourceConfig {

    @Autowired
    @Qualifier("primaryDataSource")
    private DataSource primaryDataSource;

    @Autowired
    @Qualifier("secondaryDataSource")
    private DataSource secondaryDataSource;

    @Bean(name = "dynamicDataSource")
    public DataSource dynamicDataSource() {
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put("primary", primaryDataSource);
        targetDataSources.put("secondary", secondaryDataSource);

        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        dynamicDataSource.setTargetDataSources(targetDataSources);
        dynamicDataSource.setDefaultTargetDataSource(primaryDataSource); // 设置默认数据源
        return dynamicDataSource;
    }

    @Bean
    public SqlSessionFactory sqlSessionFactory(@Qualifier("dynamicDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(dataSource);
        return sessionFactory.getObject();
    }
}

@Component
public class DataSourceInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 根据请求路径或其他条件设置数据源
        if (request.getRequestURI().startsWith("/api/secondary")) {
            DynamicDataSource.setDataSource("secondary");
        } else {
            DynamicDataSource.setDataSource("primary");
        }
        return true;
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        DynamicDataSource.clearDataSource(); // 清理线程局部变量
    }
}

@Intercepts({@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),
             @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})})
public class DataSourceInterceptor implements Interceptor {

    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        try {
            // 假设有一个方法可以根据某些条件确定要使用的数据源
            String dataSourceKey = determineDataSourceKey(invocation.getMethod().getName());
            DynamicDataSource.setDataSource(dataSourceKey);

            return invocation.proceed();
        } finally {
            DynamicDataSource.clearDataSource();
        }
    }

    @Override
    public Object plugin(Object target) {
        return Plugin.wrap(target, this);
    }

    @Override
    public void setProperties(Properties properties) {
    }
}

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Autowired
    private DataSourceInterceptor dataSourceInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(dataSourceInterceptor).addPathPatterns("/**");
    }
}

@Configuration
public class MyBatisConfig {

    @Autowired
    private DataSourceInterceptor myBatisDataSourceInterceptor;

    @Bean
    public SqlSessionFactory sqlSessionFactory(@Qualifier("dynamicDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(dataSource);
        sessionFactory.setPlugins(new Interceptor[]{myBatisDataSourceInterceptor});
        return sessionFactory.getObject();
    }
}