java Android DefaultHttpClient POST方法无法设置内容长度，收到Http错误411

Question

我对安卓4.2上的HttpPost有问题。我正在尝试调用托管在服务器中的身份验证服务。NET WebAPI服务

该服务要求请求作为POST方法发出，并提供多个自定义请求头。请求主体向服务发送Json值

以下是我如何撰写我的请求

HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://api.fekke.com/api/account/login");
httppost.addHeader(HTTP.TARGET_HOST, "api.fekke.com");
httppost.addHeader("Accept", "application/json");
httppost.addHeader("Fekke-AccessKey", "some-access-key");
httppost.addHeader("Date", dateString);
httppost.addHeader("Fekke-Signature", "some-encoded-value");
httppost.addHeader("Content-Type", "application/json; charset=utf-8");

String jsonmessage = "{\"Username\": \"myusername\", \"Password\": \"mypassword987\"}";
httppost.setEntity(new StringEntity(jsonmessage, HTTP.UTF_8));

HttpResponse response = httpclient.execute(httppost);

我试着用一个“Content Length”头调用它，它抛出一个异常，表示请求中已经存在该头

我也尝试过使用HttpURLConnection对象来调用它，从现在开始，谷歌建议使用HttpURLConnection对象，但这也遇到了同样的问题

我已经能够从iOS和。NET没有问题，所以我知道这不是服务

更新#1

我通过本地版本的服务运行了下面的示例，当我在其中一个http头中传递哈希值时，我能够将错误隔离到。我使用的是一个JWT安全令牌，它使用HMAC SHA-256哈希算法来设置服务使用的值。这个散列值会导致请求的执行中断

更新#2

我终于解决了这个问题。该问题是由Base64 encodeToString方法向值中添加不可见字符引起的。这迫使头球破发。我使用的是默认设置0或Base64。违约我将值更改为Base64。没有包装，解决了问题

Answer 1

如果使用了正确的方法，就不必担心在帖子上设置“内容长度”标题。对于Post，您通常使用一些重载版本的“SetEntity（$Type stream/string/encodedArray…）

看看这个source（搜索长度）来看看API如何处理帖子长度的例子

您应该评估将用于http的库，并找到显示“setEntity”等方法来设置帖子正文的帖子示例。这样，就不会出现与内容长度相关的错误。见example

示例代码“HttpConnection”类-使用我评论中的链接

对于JSON或位图：

try {                       
    HttpResponse response = null;
    switch (method) {
    case GET:
        HttpGet httpGet = new HttpGet(url);             
        response = httpClient.execute(httpGet);
        break;
    //Note on NIO - using a FileChannel and  mappedByteBuffer may be NO Faster
    // than using std httpcore  http.entity.FileEntity
    case POST:
        //TODO bmp to stream to bytearray for data entity
        HttpPost httpPost = new HttpPost(url); //urlends "audio OR "pic" 
        if (  !url.contains("class") ){                 
            ByteArrayOutputStream stream = new ByteArrayOutputStream();
            //can alter belo for smaller uploads to parse .JPG , 40,strm
            bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);               
            httpPost.setEntity(new ByteArrayEntity(stream.toByteArray()));

        }else if(data != null && (url.contains("class"))){
            //bug data is blank
            httpPost.setEntity(new StringEntity(data));
            Log.d(TAG, "DATA in POST run-setup " +data);
        }

        response = httpClient.execute(httpPost);
        break;
    case PUT:
        HttpPut httpPut = new HttpPut(url);
        httpPut.setEntity(new StringEntity(data));
        response = httpClient.execute(httpPut);
        break;
    case DELETE:
        response = httpClient.execute(new HttpDelete(url));
        break;
    case BITMAP:
        response = httpClient.execute(new HttpGet(url));
        processBitmapEntity(response.getEntity());
        break;
    }
    if (method < BITMAP)
        processEntity(response.getEntity());
} catch (Exception e) {
    handler.sendMessage(Message.obtain(handler,
            HttpConnection.DID_ERROR, e));
}

对于Post中的XML正文：

try {
    HttpResponse response = null;
    switch (method) {

    case POST:
        HttpPost httpPost = new HttpPost(url);
        if (data != null){
            System.out.println(" post data not null ");
            httpPost.setEntity(new StringEntity(data));
        }
        if (entry != null){
            ContentProducer cp = new ContentProducer() {
                public void writeTo(OutputStream outstream) throws IOException {

                     ExtensionProfile ep = new ExtensionProfile();
                     ep.addDeclarations(entry);
                     XmlWriter xmlWriter = new XmlWriter(new OutputStreamWriter(outstream, "UTF-8"));
                     entry.generate(xmlWriter, ep);
                     xmlWriter.flush();
                }
            };
            httpPost.setEntity(new EntityTemplate(cp));
        }
        httpPost.addHeader("GData-Version", "2");
        httpPost.addHeader("X-HTTP-Method-Override", "PATCH");
        httpPost.addHeader("If-Match", "*");
        httpPost.addHeader("Content-Type", "application/xml");
        response = httpClient.execute(httpPost);

        break;
    }
    if (method < BITMAP)
        processEntity(response.getEntity());
} catch (Exception e) {
    handler.sendMessage(Message.obtain(handler,
            HttpConnection.DID_ERROR, e));
}