Question

我正在为RequestContextHolder编写测试。我通过了测试但是在重构后我得到了NullPointerException，但无法弄清楚原因。

这是代码。

    String processorName = "<UNKNOWN>".intern();
    Optional<HttpServletRequest> request = Optional.of(((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest());
    String procName = (String) request.get().getAttribute(CONTROLLER_NAME);

    if (!Strings.isEmpty(procName)) {
        processorName = procName;
    }

    return processorName;

这是我的测试

@Test
public void testProcessorName() throws Exception {
    MockHttpServletRequest request = new MockHttpServletRequest();
    request.setAttribute(CONTROLLER_NAME, "default");
    RequestContextHolder.setRequestAttributes(new ServletRequestAttributes(request));

    String processorName = halUtils.processorName();
    assertEquals("default", processorName);
}

@Test
public void testProcessorNameWithoutAttribute() throws Exception {
    MockHttpServletRequest request = new MockHttpServletRequest();
    RequestContextHolder.setRequestAttributes(new ServletRequestAttributes(request));

    String processorName = halUtils.processorName();
    assertEquals("<UNKNOWN>", processorName);
}

@Test
public void testProcessorNameWithoutRequest() throws Exception {
    String processorName = halUtils.processorName();
    assertEquals("<UNKNOWN>", processorName);
}

然后我重构为一个班轮，但我得到了NullPointerException。

public String processorName() {
    return Optional.of(((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest().getAttribute(CONTROLLER_NAME)).orElse("<UNKNOWN>".intern()).toString();
}

Answer 1

你在做什么基本上是：

return Optional.of(null).orElse("<UNKNOWN>".intern()).toString();

这样做会给你一个NullPointerException，因为getAttribute(CONTROLLER_NAME)的返回值为null，Optional.of(..)不接受空参数，而在原始代码中，你用{{1}测试它的值}}

即使使用MockHttpServletRequest，Java Spring RequestContext测试也会抛出NullPointerException

1 个答案: