Java 如何为异常编写Junit

我的类包含以下handleException方法，我必须为其编写具有完整代码覆盖率的JUnit。因为我是新手，有人能帮我吗

public void handleException(Exception exception, DCMRequestDTO requestDTO, DCMResponseDTO responseDTO, String callType) {
    logger.error("Exception occured for deviceId:" + requestDTO.getDeviceID() + ",RefNum:"+
            requestDTO.getRefNum() + ",Operation:" + requestDTO.getOperation() + "::" + exception.getMessage());
    exception.printStackTrace();
    String errorMessageKey = "GENERIC_EXCEPTION";
    if (exception instanceof TooManyInflightException) {
        errorMessageKey = "THROTTLE_EXCEPTION";
    } else if (exception.getCause() instanceof SocketTimeoutException ||
            (exception.getCause() != null && exception.getCause().getCause() instanceof SocketTimeoutException)) {
        errorMessageKey = "TIMEOUT_EXCEPTION";
    } else if (exception.getCause().getCause() instanceof ConnectException || exception.getCause().getCause() instanceof ConnectTimeoutException || exception.getCause().getCause() instanceof UnknownHostException || exception.getCause().getCause() instanceof MalformedURLException || exception.getCause().getCause() instanceof SocketException || (exception.getMessage().indexOf("404 Error") != -1)) {
        errorMessageKey = "CONNECTION_EXCEPTION";
    } else if(exception.getMessage().indexOf("500")!=-1){
        errorMessageKey = "INTERNAL_ERROR";
    }
    /*
     * else if (exception instanceof DCMException) { if (exception.getCause().getCause() instanceof SocketTimeoutException) { errorMessageKey = "TIMEOUT_EXCEPTION"; } else if (exception.getCause().getCause() instanceof ConnectException || exception.getCause().getCause() instanceof IOException || exception.getCause().getCause() instanceof SocketException || (exception.getMessage().indexOf("404 Error") != -1)) { errorMessageKey = "CONNECTION_EXCEPTION"; } }
     */
    // logger.error(errorMessageKey + " occured in DCMServiceImpl :: UniqueId = " + requestDTO.getUniqueId() + ", RefNum = " + requestDTO.getRefNum() + ", Operation = " + requestDTO.getOperation() + ", callType = " + callType, exception);
    // added for reset time while exception occured
    responseDTO.setErrorCode(0);
    responseDTO.setErrorString(smartGraphUtils.getProperty(errorMessageKey));
    responseDTO.setStackTrace(exception.toString());
    responseDTO.setHasJson(false);
    requestDTO.setHidResolveGetRetrains("Undetermined");
}

---

根据您的源代码，您需要测试中周围类的实例：然后您应该能够调用方法

handleException

。 每个测试应该（在最好的情况下）只包含一个断言。这使得您很容易理解当前正在检查的内容。 以下是一个例子：

public final class MessageBusTest {
    @Test(expected = NullPointerException.class)
    public void registerWithNullThrowsNullPointerException() {
        MessageBus.INSTANCE.register(null);
    }
}

注释

@Test

帮助JUnit找出类中哪些方法是测试。在我的示例中，我使用

null

调用一个方法，并期望抛出一个异常，因此

expected=NullPointerException.class

---

例如，在您的情况下，您必须为测试准备适当的

异常

，然后首先使用

assertEquals

检查

requestDTO

中的内容，即错误字符串，您的方法有许多流，您需要为方法中的每个流/条件编写测试，以确保所有场景都得到处理

下面提供了示例代码，您可以编写完整的逻辑：

import org.junit.Test;

    public class HandleExceptionText {

        @Test
        public void testHandleExceptionForTooManyInflightException()  {
            //throw TooManyInflightException exception and then call handleException()
            //Example using Mockito: when(obj.method(parms)).thenThrow(new TooManyInflightException());
            //Assert to check responseDTO values have been set
        }

        @Test
        public void testHandleExceptionForSocketTimeoutException()   {
            //throw SocketTimeoutException exception and then call handleException()
            //Example using Mockito: when(obj.method(parms)).thenThrow(new SocketTimeoutException());
            //Assert to check responseDTO values have been set
        }

        @Test
        public void testHandleExceptionForConnectTimeoutException()   {
            //throw ConnectTimeoutException exception and then call handleException()
            //Example using Mockito: when(obj.method(parms)).thenThrow(new ConnectTimeoutException());
            //Assert to check responseDTO values have been set
        }

        @Test
        public void testHandleExceptionForConnectException()   {
            //throw ConnectException exception and then call handleException()
            //Example using Mockito: when(obj.method(parms)).thenThrow(new ConnectException());
            //Assert to check responseDTO values have been set
        }

        @Test
        public void testHandleExceptionForUnknownHostException()   {
            //throw UnknownHostException exception and then call handleException()
            //Example using Mockito: when(obj.method(parms)).thenThrow(new UnknownHostException());
            //Assert to check responseDTO values have been set
        }

        @Test
        public void testHandleExceptionForMalformedURLException()   {
            //throw MalformedURLException exception and then call handleException()
            //Example using Mockito: when(obj.method(parms)).thenThrow(new MalformedURLException());
            //Assert to check responseDTO values have been set
        }

        @Test
        public void testHandleExceptionForConnectException()  {
            //throw SocketException exception and then call handleException()
            //Example using Mockito: when(obj.method(parms)).thenThrow(new SocketException());
            //Assert to check responseDTO values have been set
        }

    }

此外，我建议浏览以下JUnit和Mockito教程链接：

---

@Test public final void testhandleException（）抛出异常{给定（smartGraphServiceHelper.generateDocument（Mockito.any（DCMRequestDTO.class）））。willThrow（new SocketTimeoutException（））；字符串callType=“”；smartGraphService.handleException（异常，requestDTO，responseDTO，callType）；assertEquals（“0”，responseDTO.getErrorCode（）)}这是我尝试过的方法，但当它进入exception.getCause（）内部时，会给出null指针