spring中使用mockito

1 mockito介紹和入門

官方：https://github.com/mockito/mockito

入門：

5分鍾了解Mockito http://liuzhijun.iteye.com/blog/1512780

Mockito：一個強大的用於 Java 開發的模擬測試框架 http://www.oschina.net/translate/mockito-a-great-mock-framework-for-java-development

2 spring中正常使用mockito

上demo代碼：

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "classpath:testApplicationContext.xml" })
public class SpringMockitoTest {
 
    @Mock
    private ApiService mockApiService;
 
    @Before
    public void initMocks() {
        MockitoAnnotations.initMocks(this);
        when(mockApiService.test()).thenReturn("ok");
    }
 
    @Test
    public void should_success_when_testApiService() {
        String result = mockApiService.test();
        Assert.assertEquals("ok", result);
    }
}
 
@Component
public class ApiService {
 
    @Autowired
    private TestApiService testApiService;
 
    public String test() {
        String connect = testApiService.connect();
        connect += "test";//test自己的業務
        return connect;
    }
}
 
@Component
public class TestApiService {
    public String connect() {
        return "error";
    }
 
    public String  findFromDb() {
        return "db_data";
    }
}

正常使用spring和mockito中，我們把需要的mock的ApiService給mock掉，但是我們更想的是把TestApiService中的connect方法mock掉，這樣就可以測試我們自己的代碼，也就是ApiService中test方法自己的業務。

3 spring中mock任何容器內對象

上面的demo中，我們如何mock掉TestApiService中的test方法？

因為TestApiService是spring容器管理的bean，並且ApiService中使用到TestApiService，所以我們把ApiService中引用的TestApiService替換成我們的mock對象即可。

Spring框架有個反射工具ReflectionTestUtils，可以把一個對象中屬性設置為新值，我們可以使用：

ReflectionTestUtils.setField(apiService, "testApiService", spyTestApiService);

把我們mock的testApiService放到apiService中，這樣apiService調用就是我們mock的對象了；但是默認spring中apiService對象是代理對象，不能直接把值設置到屬性上，所以我們自己寫個小的工具類，在最后如下：

ReflectionTestUtils.setField(AopTargetUtils.getTarget(apiService), "testApiService", spyTestApiService);

完整demo：

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "classpath:testApplicationContext.xml" })
public class SpringMockitoTest {
 
    @Autowired
    private ApiService apiService;
    @Mock
    private TestApiService spyTestApiService;
    @Autowired
    private TestApiService testApiService;
 
    @Before
    public void initMocks() throws Exception {
        MockitoAnnotations.initMocks(this);
        ReflectionTestUtils.setField(AopTargetUtils.getTarget(apiService), "testApiService", spyTestApiService);
        when(spyTestApiService.connect()).thenReturn("ok");
    }
 
    @After
    public void clearMocks() throws Exception {
        ReflectionTestUtils.setField(AopTargetUtils.getTarget(apiService), "testApiService", testApiService);
    }
 
    @Test
    public void should_success_when_testApiService() {
        String result = apiService.test();
        Assert.assertEquals("oktest", result);
    }
}
 
@Component
public class ApiService {
 
    @Autowired
    private TestApiService testApiService;
 
    public String test() {
        String connect = testApiService.connect();
        connect += "test";//test自己的業務
        return connect;
    }
}
 
@Component
public class TestApiService {
    public String connect() {
        return "error";
    }
 
    public String  findFromDb() {
        return "db_data";
    }
}
 
public class AopTargetUtils {
    /** 
     * 獲取 目標對象 
     * @param proxy 代理對象 
     * @return  
     * @throws Exception 
     */
    public static Object getTarget(Object proxy) throws Exception {  
        if(!AopUtils.isAopProxy(proxy)) {  
            return proxy;//不是代理對象  
        }  
        if(AopUtils.isJdkDynamicProxy(proxy)) {  
            return getJdkDynamicProxyTargetObject(proxy);  
        } else { //cglib  
            return getCglibProxyTargetObject(proxy);  
        }  
    }  
 
    private static Object getCglibProxyTargetObject(Object proxy) throws Exception {  
        Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0");  
        h.setAccessible(true);  
        Object dynamicAdvisedInterceptor = h.get(proxy);  
        Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");  
        advised.setAccessible(true);  
        Object target = ((AdvisedSupport)advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();  
        return target;  
    }  
 
 
    private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception {  
        Field h = proxy.getClass().getSuperclass().getDeclaredField("h");  
        h.setAccessible(true);  
        AopProxy aopProxy = (AopProxy) h.get(proxy);  
        Field advised = aopProxy.getClass().getDeclaredField("advised");  
        advised.setAccessible(true);  
        Object target = ((AdvisedSupport)advised.get(aopProxy)).getTargetSource().getTarget();  
        return target;  
    }  
}

最后就是注意測試之后要還原現場，把spring對象還原，尤其在跑maven test的時候，否則可能會影響其他人的測試。