如何使用DefaultHttpClient写入OutputStream？

Question

我如何OutputStream使用org.apache.http.impl.client.DefaultHttpClient？

我想写一个长字符串到输出流.

使用HttpURLConnection你会像这样实现它:

HttpURLConnection connection = (HttpURLConnection)url.openConnection();
OutputStream out = connection.getOutputStream();
Writer wout = new OutputStreamWriter(out);
writeXml(wout);

有没有使用DefaultHttpClient类似于我上面的方法？我如何写一个OutputStream使用DefaultHttpClient而不是HttpURLConnection？

例如

DefaultHttpClient client = new DefaultHttpClient();

OutputStream outstream = (get OutputStream somehow)
Writer wout = new OutputStreamWriter(out);

Answer 1

我知道另一个答案已被接受,只是为了记录这是如何用HttpClient写出内容而不在内存中进行中间缓冲.

    AbstractHttpEntity entity = new AbstractHttpEntity() {

        public boolean isRepeatable() {
            return false;
        }

        public long getContentLength() {
            return -1;
        }

        public boolean isStreaming() {
            return false;
        }

        public InputStream getContent() throws IOException {
            // Should be implemented as well but is irrelevant for this case
            throw new UnsupportedOperationException();
        }

        public void writeTo(final OutputStream outstream) throws IOException {
            Writer writer = new OutputStreamWriter(outstream, "UTF-8");
            writeXml(writer);
            writer.flush();
        }

    };
    HttpPost request = new HttpPost(uri);
    request.setEntity(entity);

Answer 2

您无法直接从BasicHttpClient获取OutputStream.您必须创建一个HttpUriRequest对象并为其提供一个HttpEntity封装您要发送的内容的对象.例如,如果输出小到足以适合内存,则可能会执行以下操作:

// Produce the output
ByteArrayOutputStream out = new ByteArrayOutputStream();
Writer writer = new OutputStreamWriter(out, "UTF-8");
writeXml(writer);

// Create the request
HttpPost request = new HttpPost(uri);
request.setEntity(new ByteArrayEntity(out.toByteArray()));

// Send the request
DefaultHttpClient client = new DefaultHttpClient();
HttpResponse response = client.execute(request);

如果数据足够大以至于需要对其进行流式传输,则会变得更加困难,因为没有HttpEntity接受OutputStream的实现.您需要写入临时文件并使用FileEntity或可能设置管道并使用InputStreamEntity

编辑请参阅oleg的答案,了解演示如何流式传输内容的示例代码 - 毕竟,您不需要临时文件或管道.