使用MockMultipartHttpServletRequest进行单元测试（在ItemInputStream.makeAvailable中引发NullPointerException）

Question

我编写了一个转换器类，该类使用HttpServletRequest并将其转换为另一个类型，该类型包含指向Servlet请求的InputStream的指针。（其想法是从请求处理中抽象传入的传输协议，因此，例如，我也可以从FTP编写类似的转换器。）

现在，我正在尝试为此编写单元测试，但遇到了问题。我设法找出正确的样板来创建一个有效的Multipart HTTP请求（使用Spring类MockMultipartHttpServletRequest和MockMultipartFile），但是现在我在类的initialize()方法中得到了NullPointerException UploadRequest。我猜的问题是，MockMultipartHttpServletRequest内部的流以某种方式未正确初始化，但是我不知道该怎么做。

任何建议将不胜感激！

这是堆栈跟踪：

java.lang.NullPointerException
    at org.apache.commons.fileupload.MultipartStream$ItemInputStream.makeAvailable(MultipartStream.java:976)
    at org.apache.commons.fileupload.MultipartStream$ItemInputStream.read(MultipartStream.java:886)
    at java.io.InputStream.read(InputStream.java:82)
    at org.apache.commons.fileupload.util.Streams.copy(Streams.java:96)
    at org.apache.commons.fileupload.util.Streams.copy(Streams.java:66)
    at org.apache.commons.fileupload.MultipartStream.readBodyData(MultipartStream.java:592)
    at org.apache.commons.fileupload.MultipartStream.discardBodyData(MultipartStream.java:618)
    at org.apache.commons.fileupload.MultipartStream.skipPreamble(MultipartStream.java:637)
    at org.apache.commons.fileupload.FileUploadBase$FileItemIteratorImpl.findNextItem(FileUploadBase.java:984)
    at org.apache.commons.fileupload.FileUploadBase$FileItemIteratorImpl.<init>(FileUploadBase.java:965)
    at org.apache.commons.fileupload.FileUploadBase.getItemIterator(FileUploadBase.java:331)
    at org.apache.commons.fileupload.servlet.ServletFileUpload.getItemIterator(ServletFileUpload.java:148)
    at com.ooyala.UploadRequest.initialize(UploadRequest.java:51)
    at com.ooyala.UploadRequestTest.testCreateFromServletRequest(UploadRequestTest.java:57)

这是我的转换器类的缩写版本：

public class UploadRequest {
  private Map<String, String> params;
  private InputStream strIn;
  private Logger Log = Logger.getLogger(UploadRequest.class.getName());

  public UploadRequest()
  {
    params = new HashMap<String, String>();
  }

  public void initialize(HttpServletRequest sRequest, 
                         ServletFileUpload upload)
    throws IOException, FileUploadException
  {
    Enumeration<String> paramNames = sRequest.getParameterNames();
    while (paramNames.hasMoreElements()) {
      String pName = paramNames.nextElement();
      params.put(pName, sRequest.getParameter(pName));
    }
    params.put("request_uri", sRequest.getRequestURI());

    FileItemIterator iter = upload.getItemIterator(sRequest);
    while (iter.hasNext()) {
      FileItemStream item = iter.next();
      try {
        if (!item.isFormField()) {
          // Skip form fields
          params.put("original_file_name", item.getName());
          strIn = item.openStream();
        } 
      } catch (IOException ex) {
        Log.severe("File uploading exception: " + ex.getMessage());
        throw ex;
      }
    }
  }

这是单元测试：

import org.springframework.mock.web.MockMultipartHttpServletRequest;
import org.springframework.mock.web.MockMultipartFile;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
// etc.... other imports

@RunWith(JMock.class)
public class UploadRequestTest {
  private UploadRequest upRequest;

  @Before
    public void setUp()
    {
      context.setImposteriser(ClassImposteriser.INSTANCE);
      upRequest = new UploadRequest();
    }

  @Test
    public void testCreateFromServletRequest()
      throws IOException, FileUploadException
    {
      String text_contents = "hello world";

      MockMultipartHttpServletRequest sRequest = 
        new MockMultipartHttpServletRequest();
      sRequest.setMethod("POST");
      String boundary = generateBoundary();
      String contentType = "multipart/form-data; boundary="+boundary;
      sRequest.setContentType(contentType);
      sRequest.setRequestURI("/foo");
      sRequest.addParameter("test_param","test_value");
      sRequest.addFile(
        new MockMultipartFile("file1","test_upload.txt","text/plain",
          text_contents.getBytes()));

      ServletFileUpload upload = new ServletFileUpload();
      assertTrue(upload.isMultipartContent(sRequest));

      upRequest.initialize(sRequest, upload);
    }
}

Answer 1

我从库中插入了源代码，无论如何，您都需要发送内容。库可能需要在skip方法中检查它是否为null

MockMultipartHttpServletRequest request
request.setContent("whatever".getBytes());

为其他人张贴在这里