Spring MVC UT中的NPE

代码很简单，是对Srping MVC工程controller的一个测试，用的Junit框架。测试代码如下

 import static org.junit.Assert.*;

import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.ContextHierarchy;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;

import org.springframework.test.web.servlet.result.MockMvcResultHandlers;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;

@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextHierarchy({
@ContextConfiguration(name="parent",locations="classpath:spring-test.xml"),
@ContextConfiguration(name="child", locations="classpath:spring-test-web.xml")
})

public class MomUserInfoControllerTest {
private MockMvc mockMvc;

@Autowired 
private WebApplicationContext wac;


@Before
public void setUp() throws Exception {
    mockMvc=MockMvcBuilders.webAppContextSetup(wac).build();

}

@Test
public void testBriefUser() throws Exception {      
    mockMvc.perform(get("/briefUser/3")).andDo(MockMvcResultHandlers.print()).andReturn();

}

但是这个case抛出了NPE，原因是我有个spring的拦截器，从request中取得一些信息，代码如下：

 @Component
public class I18nInterceptor extends AbstractInterceptor {
 private static final Logger logger =       LoggerFactory.getLogger(I18nInterceptor.class);
  @Autowired
 private HttpServletRequest request;

@Override
public void preInvoke(MethodInvocation invocation) {
WebApplicationContext wc =ContextLoader.getCurrentWebApplicationContext();
  RequestInfo requestInfo = wc.getBean("requestInfo", RequestInfo.class);
  String locale = request.getParameter("locale");
logger.info("Set the locale to " + locale);

问题来了..wc是空值，就是ContextLoader.getCurrentWebApplicationContext();娶不到值，因此该测试会有空指针，也无法进行下去。不知道大家有啥办法解决？我想应该是@RunWith(SpringJUnit4ClassRunner.class)这个注解导致了这个启动的webapplicationcontext的问题，不知道是不是

此处需要注意 一定要ContextLoaderListener 才行 即只有它才能通过 ContextLoader.getCurrentWebApplicationContext(); 获取

http://bbs.csdn.net/topics/390895754