如何在spring测试中动态设置环境变量

@ContextConfiguration(initializers = TestContextInitializer.class)
@RunWith(SpringRunner.class)
@SpringBootTest(classes = {TestServiceApplication.class})

public class SampleTest {
    @org.junit.Test
    public void getContactsByName() throws Exception {
    }

}

public class TestContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
    @Override
    public void initialize(ConfigurableApplicationContext configurableApplicationContext) {
        System.setProperty("DATA_DB_URL","some_url");
        System.setProperty("DATA_DB_USER","some_user");
        System.setProperty("DATA_DB_PASSWORD","some_password");
        System.setProperty("DATA_DB_POOL_SIZE","2");
        System.setProperty("DATA_DB_ROW_PREFETCH_SIZE","50");
    }
}