Android Http 从 Servlet 获取字符串数据

Question

我正在尝试获取从 android 中的 java servlet 返回的简单 url 字符串。我能够取回 url，但它前面有一个空值。

这是我用来调用 servlet 的 Android 代码:

HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet("http://localhost:8888/mcheck_gen_url_fu");
HttpResponse response = client.execute(request);
//Here i try to read the response
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
while ((line = rd.readLine()) != null) {
    output += line + System.getProperty("line.separator");
}
//I am able to get the response but there is a null pre-pended 

这是 servlet 代码:

public class mcheck_gen_url_fu extends HttpServlet {
    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {

        BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
        String output = blobstoreService.createUploadUrl("/mcheck_file_upload");

        resp.setContentType("text/plain");
        resp.getWriter().print(output);
    }
}

这是 url 的样子:

nullhttp://anyusers-MacBook-Air.local:8888/_ah/upload/ag5tY2hlY2stcGF5bWVudHIbCxIVX19CbG9iVXBsb2FkU2Vzc2lvbl9fGBwM

这样做正确吗？我尝试了 Gson，但它也被 null 阻塞了。

提前致谢。

Answer 1

    output = "";
    while ((line = rd.readLine()) != null) {
        output += line + System.getProperty("line.separator");
    }

顺便说一句，最好的做法是

final StringBuilder sb = new StringBuilder();
final String sep = System.getProperty("line.separator");
while ((line = rd.readLine()) != null) {
        sb.append(line).append(sep);
}

output = sb.toString();