Android HTTPPost返回错误“方法不允许。”

Question

我正在编写一个Android 2.2应用程序，该应用程序将JSON严格性过帐到ReSTfull Web服务。

Fiddler对Web服务的调用具有与预期相同的Json返回，而对ASPX Web应用程序具有与预期的相同Json返回。

当我查看服务器日志时，可以看到服务器使用307重定向响应初始POST动词，然后立即响应GET和405错误。

Fiddler和aspx应用程序记录一个307重定向的POST，然后立即另一个POST和200 OK。

到底是怎么回事？

这是主要活动：

package com.altaver.android_PostJson2;

import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class PostJson extends Activity {
     private static final String TAG = "MainActivity";
     private static final String URL = "http://web2.altaver.com/sdz/avReSTfulLogin1";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        JSONObject jsonObjSend = new JSONObject();

        try {
         jsonObjSend.put("Pass", "sz");
         jsonObjSend.put("User", "szechman");


         Log.i(TAG, jsonObjSend.toString(2));

        } catch (JSONException e) {
            e.printStackTrace();
        }

        JSONObject jsonObjRecv = HttpClient.SendHttpPost(URL, jsonObjSend);

//examine JSONObject later
    }
}

这是进行Web服务调用的类代码：

package com.altaver.android_PostJson2;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.params.HttpClientParams;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONObject;

import android.util.Log;

public class HttpClient {

    private static final String TAG = "HttpClient";


    public static JSONObject SendHttpPost(String URL, JSONObject jsonObjSend) {

          try {
           DefaultHttpClient httpclient = new DefaultHttpClient();

           HttpClientParams.setRedirecting(httpclient.getParams(), true);

           //added cookie policy, wild shot in the dark
           //httpclient.getParams().setParameter(ClientPNames.COOKIE_POLICY, >CookiePolicy.RFC_2109);

           HttpPost httpPostRequest = new HttpPost(URL);

           StringEntity se;
           se = new StringEntity(jsonObjSend.toString());

           // Set HTTP parameters
           httpPostRequest.setEntity(se);

           //httpPostRequest.setHeader("User-Agent", >"com.altaver.android_PostJson2");
           httpPostRequest.setHeader("User-Agent", "Mozilla/5.0 (Windows; U; >Windows NT 5.1; en-US; rv:1.9.2.3) Gecko/20100401");

           httpPostRequest.setHeader("Accept", "application/json");
           httpPostRequest.setHeader("Content-Type", "application/json");

           long t = System.currentTimeMillis();
           HttpResponse response = (HttpResponse) >httpclient.execute(httpPostRequest);
           Log.i(TAG, "HTTPResponse received in [" + >(System.currentTimeMillis()-t) + "ms]");

           HttpEntity entity = response.getEntity();

           if (entity != null) {
            InputStream instream = entity.getContent();
            Header contentEncoding = response.getFirstHeader("Content-Encoding");


            String resultString= convertStreamToString(instream);
            instream.close();
            resultString = resultString.substring(1,resultString.length()-1); // >remove wrapping "[" and "]"

            JSONObject jsonObjRecv = new JSONObject(resultString);
            Log.i(TAG,"<jsonobject>\n"+jsonObjRecv.toString()+"\n</jsonobject>");

            return jsonObjRecv;
           }

          }
          catch (Exception e)
          {
           e.printStackTrace();
          }
          return null;
         }

    private static String convertStreamToString(InputStream is) {
          /*
           * To convert the InputStream to String we use the >BufferedReader.readLine()
           * method. We iterate until the BufferedReader return null which means
           * there's no more data to read. Each line will appended to a >StringBuilder
           * and returned as String.
           * 
           * (c) public domain: http://senior.ceng.metu.edu.tr/2009/praeda/2009/01>/11/a-simple-restful-client-at-android/
           */
          BufferedReader reader = new BufferedReader(new InputStreamReader(is));
          StringBuilder sb = new StringBuilder();

          String line = null;
          try {
           while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
           }
          } catch (IOException e) {
           e.printStackTrace();
          } finally {
           try {
            is.close();
           } catch (IOException e) {
            e.printStackTrace();
           }
          }
          return sb.toString();
    }
}

Answer 1

在网址末尾添加“ /”会导致重定向发生，因为您的服务器喜欢以“
/”结尾的网址。服务器将您重定向到的URL完全支持POST，但是当客户端根据setRedirecting（）调用的行为运行时，客户端将执行GET请求（cURL与-
L开关执行相同的操作）解决方法是要么URL末尾的’/’，或者您自己从响应中获取Location标头，然后手动启动另一个POST请求。

这可以在wireshark中观察到。您可以通过尝试使用浏览器对URL附加一个斜杠的GET请求来测试该理论。这将导致浏览器得到405。这是Android的固定代码，此代码使用简单的修复方法，即在URL后面附加一个“
/”（尚未投入生产）：

 package com.altaver.demo;

import java.io.IOException;
import java.io.UnsupportedEncodingException;

import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.HttpResponseException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.params.HttpClientParams;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;

public class AltaVerDemoActivity extends Activity {
    private static final String TAG = "MainActivity";
    private static final String URL = "http://96.56.2.188/sdz/avReSTfulLogin1/";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        JSONObject jsonObjSend = new JSONObject();
        try {
            jsonObjSend.put("Pass", "sz");
            jsonObjSend.put("User", "szechman");
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        HttpClient client = new DefaultHttpClient();
        HttpPost httpPostRequest = new HttpPost(URL);
        httpPostRequest.setHeader("User-Agent", "com.altaver.android_PostJson2");
        httpPostRequest.setHeader("Accept", "application/json");
        httpPostRequest.setHeader("Content-Type", "application/json");
        StringEntity se = null;
        try {
            se = new StringEntity(jsonObjSend.toString());
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        httpPostRequest.setEntity(se);
        HttpResponse response = null;
        try {
            response = client.execute(httpPostRequest);
        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
            Toast.makeText(getApplicationContext(),
                    "Please check your internet connection",
                    Toast.LENGTH_SHORT).show();
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        BasicResponseHandler responseHandler = new BasicResponseHandler();
        String strResponse = null;
        if (response != null) {
            try {
                strResponse = responseHandler.handleResponse(response);
            } catch (HttpResponseException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        Log.e("AltaVerDemoActivity", "Response: " + strResponse);
    }
}