struts2 action类的两种测试方法产生80毫秒的执行速度差异

现在在做一个项目，使用struts2+spring，在页面访问时感觉特别慢，就对action做了下测试，把执行时间打印出来，发现为action注入service（逻辑层类）时，两种不同的注入方法产生80甚至几百毫秒的速度差异，请看：

action类：

public class HubAction extends BaseActionSupport {
	private HubService hubService;

	// findHub
	private long hubId;

	private Hub hub;

	/**
	 * 根据hubId查找hub
	 * 
	 * @return
	 */
	public String findHub() {
		long start = System.currentTimeMillis();
		System.out.println("============action.findHub开始==>" + start);
		hub = hubService.getHub(hubId);
		long end = System.currentTimeMillis();
		System.out.println("============action.findHub开始==>" + end);
		System.out.println("============action.findHub差值==>" + (end - start));
		return SUCCESS;
	}
	public void setHubService(HubService hubService) {
		this.hubService = hubService;
	}
	
	public long getHubId() {
		return hubId;
	}

	public void setHubId(long hubId) {
		this.hubId = hubId;
	}

	public Hub getHub() {
		return hub;
	}
}

service类：

public class HubService extends BaseService {
	private HubDao hubDao;

	public Hub getHub(long hubId) {
		long start = System.currentTimeMillis();
		System.out.println("service.getHub开始==>" + start);
		Hub hub = hubDao.getHub(hubId);
		long end = System.currentTimeMillis();
		System.out.println("service.getHub结束==>" + end);
		System.out.println("service.getHub差值==>" + (end - start));
		return hub;
	}

	public void setHubDao(HubDao hubDao) {
		this.hubDao = hubDao;
	}
}

第一种测试方法：

public class HubActionTest extends BaseActionTestCase {
	private HubAction action;

	private HubService hubService;

	protected void setUp() throws Exception {
		super.setUp();
		hubService = (HubService) ctx.getBean("hubService");
	}

	protected void tearDown() throws Exception {
		super.tearDown();
		action = null;
	}

	public void testExecute() throws Exception {
		action = new HubAction();
		action.setHubService(hubService);

		long hubId = 92387951116L;
		action.setHubId(hubId);
		for (int i = 0; i < 10; i++) {
			System.out
					.println("hubService.hashcode==>" + hubService.hashCode());
			long s = System.currentTimeMillis();
			System.out.println("------------------------testExecute开始==>" + s);
			action.findHub();
			long e = System.currentTimeMillis();
			System.out.println("------------------------testExecute结束==>" + e);
			System.out.println("------------------------差值==>" + (e - s));
		}

		// set mock response so setting cookies doesn't fail
		ServletActionContext.setResponse(new MockHttpServletResponse());

	}
}
[color=red]BaseActionTestCase来则appfuse项目，去掉了一些处理mail的代码。[/color]
public abstract class BaseActionTestCase extends TestCase {
	protected transient final Log log = LogFactory.getLog(getClass());

	protected static XmlWebApplicationContext ctx;

	protected MockHttpServletRequest request = new MockHttpServletRequest();

	// This static block ensures that Spring's BeanFactory is only loaded
	// once for all tests
	static {
		String[] paths = { "classpath*:spring/applicationContext-basic.xml",
				"classpath*:spring/applicationContext-database.xml",
				"classpath*:spring/applicationContext-service-search.xml",
				"classpath*:spring/applicationContext-service.xml" };

		ctx = new XmlWebApplicationContext();
		ctx.setConfigLocations(paths);
		ctx.setServletContext(new MockServletContext(""));
		ctx.refresh();
	}

	protected void setUp() throws Exception {
		LocalizedTextUtil.addDefaultResourceBundle("ApplicationResources");
		ActionContext.getContext().setSession(new HashMap());

		ServletActionContext.setRequest(request);
	}

	protected void tearDown() throws Exception {
		ActionContext.getContext().setSession(null);
	}
}

第二种测试方法：

public class Hub3ActionTest extends TransactionalBaseTest {
	private HubAction action;

	private HubService hubService;

	public void setHubService(HubService hubService) {
		this.hubService = hubService;
	}

	public void testaaaa() {
		action = new HubAction();
		action.setHubService(hubService);

		long hubId = 92387951116L;
		action.setHubId(hubId);
		for (int i = 0; i < 10; i++) {
			System.out
					.println("hubService.hashcode==>" + hubService.hashCode());
			long s = System.currentTimeMillis();
			System.out.println("------------------------testExecute开始==>" + s);
			action.findHub();
			long e = System.currentTimeMillis();
			System.out.println("------------------------testExecute结束==>" + e);
			System.out.println("------------------------差值==>" + (e - s));
		}
	}
}

public class TransactionalBaseTest extends AbstractTransactionalDataSourceSpringContextTests {
	protected String[] getConfigLocations() {
		setAutowireMode(AUTOWIRE_BY_NAME);
		return new String[] { "classpath*:/**/applicationContext-*.xml" };
	}
}

第一次测试打印：
hubService.hashcode==>14274282
------------------------testExecute开始==>1206848722765
============action.findHub开始==>1206848722765
service.getHub开始==>1206848723046     这里进入service用了281毫秒
service.getHub结束==>1206848723046
service.getHub差值==>0
============action.findHub开始==>1206848723203
============action.findHub差值==>438
------------------------testExecute结束==>1206848723203
------------------------差值==>438     总的执行时间 438 毫秒

.....打印了10次，以下省略

第二次测试打印：
hubService.hashcode==>9422759
------------------------testExecute开始==>1206843361421
============action.findHub开始==>1206843361421
service.getHub开始==>1206843361421     这里进入service用了0毫秒
service.getHub结束==>1206843361421
service.getHub差值==>0
============action.findHub开始==>1206843361421
============action.findHub差值==>0
------------------------testExecute结束==>1206843361421
------------------------差值==>0        总的执行时间 0 毫秒

.....打印了10次，以下省略


谁能帮忙解释下什么原因？