Apache Abdera Multipart Request throwing nullpointer Exception(IBM connection API)

问题

I am using Apache abdera to post multipart request to IBM connection 4.0 API. I am getting nullpointer exception from Abdera API. Please let me know what's the root cause.

private void createEntryWithAttachment(){
    try {
        String activityId = "urn:lsid:ibm.com:oa:662d0dc7-0308-48ee-8291-d730c733d2d1";         
        String activityIdLocal = activityId.substring(activityId.lastIndexOf(":")+1, activityId.length());
        String createEntryLocal = createEntry+activityIdLocal;      

        Abdera abdera = new Abdera();
        AbderaClient client = new AbderaClient(abdera);         
        AbderaClient.registerTrustManager();
        System.out.println("pd --->"+pd);
        client.addCookie("poktam2cl.iespc.ibm.com", "PD-S-SESSION-ID", pd, "/", null, true);

        RequestOptions requestOptions = client.getDefaultRequestOptions();
        requestOptions.setUseChunked(true);
        requestOptions.setHeader("Connection", "close");
        requestOptions.setHeader("Content-Type", "multipart/related;type=\"application/atom+xml\"");                        
        requestOptions.setContentType("multipart/related;type=\"application/atom+xml\"");
        requestOptions.setSlug("Sample.txt");


        Credentials credentials = new UsernamePasswordCredentials(username, password);
        client.addCredentials(createEntryLocal, AuthScope.ANY_REALM,AuthScope.ANY_SCHEME, credentials);

        Entry entry = abdera.getFactory().newEntry();
        entry.setTitle("create entry with attachment title ");
        entry.setContent("create entry with attachment content");

        javax.xml.namespace.QName field = new QName("http://www.ibm.com/xmlns/prod/sn", "field", "snx");
        org.apache.abdera.model.Element fieldElement = entry.addExtension(field);
        fieldElement.setAttributeValue("type", "file");
        fieldElement.setAttributeValue("name", "sampletextfile1");
        fieldElement.setAttributeValue("position", "3000");

        FileInputStream fis = new FileInputStream(filepath);
        requestOptions.setHeader("Content-Length", "35");

        entry.addCategory("http://www.ibm.com/xmlns/prod/sn/type","entry", "Entry");

        ClientResponse response = client.post(createEntryLocal, entry, fis, "multipart/related;type=\"application/atom+xml\"", requestOptions );

        System.out.println("Entry Created with attachment's resp: " + response.getStatus());

        if(response.getStatus() == 201){
            System.out.println("Entry Created with attachment successfully .....");
            printIBMConnectionErrorMessage(response);
        }else{
            System.out.println("Entry with attachment creation failed");
            printIBMConnectionErrorMessage(response);
            //System.exit(0);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
} 

Output

java.lang.NullPointerException
at org.apache.abdera.protocol.client.util.MultipartRelatedRequestEntity.writeInput(MultipartRelatedRequestEntity.java:74)
at org.apache.abdera.protocol.client.util.MultipartRelatedRequestEntity.writeRequest(MultipartRelatedRequestEntity.java:59)
at org.apache.commons.httpclient.methods.EntityEnclosingMethod.writeRequestBody(EntityEnclosingMethod.java:499)
at org.apache.commons.httpclient.HttpMethodBase.writeRequest(HttpMethodBase.java:2114)
at org.apache.commons.httpclient.HttpMethodBase.execute(HttpMethodBase.java:1096)
at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:398)
at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:323)
at org.apache.abdera.protocol.client.AbderaClient.execute(AbderaClient.java:688)
at org.apache.abdera.protocol.client.AbderaClient.post(AbderaClient.java:306)
at JavaAgentEntryWithAttachment.createEntryWithAttachment(JavaAgentEntryWithAttachment.java:157)
at JavaAgentEntryWithAttachment.main(JavaAgentEntryWithAttachment.java:66)

This exception is coming from abdera API, class called MultipartRelatedRequestEntity.java, Line no 74. I have placed line no 74 source code below. So its clear that contentSrc is null & Abdera API not allowing me to set this value. Please let me know what I am missing here.

String contentId = entry.getContentSrc().toString();

回答1:

I did in two steps:

1. Send the file
2. Call to update the data

Each with the good mime type. You can not send the file with XML mime type. And put the length of the file.

回答2:

It is possible to avoid the nullpointer and do it in one request. I had the same issue and created another issue and managed to find a solution. You can find it here.

It comes down to the following code example where you create a HttpClient Part which can contain a StringPart and a FilePart

  final Entry entry = // ... Create your Entry
  final RequestOptions options = this.client.getDefaultRequestOptions();
  options.setHeader("Content-Type", "multipart/related;type=\"application/atom+xml\"");

  StringPart entryPart = new StringPart("entry", entry.toString());
  entryPart.setContentType("application/atom+xml");

  FilePart filePart = new FilePart("file", new File(resource.getFile()));           

  RequestEntity request = new MultipartRequestEntity(new Part[] { entryPart, filePart}, this.client.getHttpClientParams());
  ClientResponse response = client.post(this.url + this.activityId, request, options);

Hope this will help people in the future if they are using Abdera.

来源：https://stackoverflow.com/questions/22845854/apache-abdera-multipart-request-throwing-nullpointer-exceptionibm-connection-ap