无法将JSONObject从android发布到PHP

我试图使用下面的代码将JSONObject从android应用程序发布到php web应用程序

String url = "http://10.0.2.2/test/"
URL rest_url = new URL(url);
JSONObject params = new JSONObject();
params.put("username","admin"); 

// Send POST data request
BufferedReader reader=null;

DataOutputStream printout;
URLConnection conn = rest_url.openConnection();
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setUseCaches(false);
conn.setRequestProperty("Content-Type", "application/json");
conn.setRequestProperty("Accept", "application/json");
OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
wr.write( params.toString());
wr.close();

当我试图用php检索用户名时，得到的是空值

 <?php echo $_POST['username'];
 ?>

---

您没有在Android代码上发送

POST

请求。您只是在打印一个普通的

字符串

，在您的示例中，它就是您的

JSONObject

。你必须改变一些东西，它才能工作

首先，将您的

conn

设置为发送

POST

conn.setRequestMethod("POST");

然后，创建

名称值对

的

列表

。就像下面的例子

List<NameValuePair> pairs = new ArrayList<NameValuePair>();
pairs.add(new BasicNameValuePair("username", params.toString()));

---

---

编辑：似乎API 22上不推荐使用

NameValuePair

，请查看更多详细信息。

您没有在Android代码上发送

POST

请求。您只是在打印一个普通的

字符串

，在您的示例中，它就是您的

JSONObject

。你必须改变一些东西，它才能工作

首先，将您的

conn

设置为发送

POST

conn.setRequestMethod("POST");

然后，创建

名称值对

的

列表

。就像下面的例子

List<NameValuePair> pairs = new ArrayList<NameValuePair>();
pairs.add(new BasicNameValuePair("username", params.toString()));

---

---

编辑：似乎API 22上不推荐使用

NameValuePair

，请查看更多详细信息。

为了避免在每个类中为连接编写HTTP代码，我这样做了

创建了单独的http类，并放置了以下代码：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

import android.util.Log;


public class HttpConnect
{
    HttpClient httpClient;
    String Url;
    private static final String                 DEBUG_TAG = "TAG";


    public HttpConnect(String url) {
        this.Url = url;
        httpClient = new DefaultHttpClient();
    }

    public HttpEntity Get() throws ClientProtocolException, IOException{

        HttpGet httpGet = new HttpGet(Url);
        HttpResponse httpResponseGet = httpClient.execute(httpGet);
        HttpEntity resEntityGet = httpResponseGet.getEntity();
        return resEntityGet;
    }

    public HttpEntity Post(HashMap<String, String> c) throws ClientProtocolException, IOException{

        HttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(Url);

        // set up post data
        ArrayList<NameValuePair> nameValuePair = new ArrayList<NameValuePair>();
        Iterator<String> it = c.keySet().iterator();
        while (it.hasNext())
        {
            String key = it.next();
            nameValuePair.add(new BasicNameValuePair(key, c.get(key)));
        }

        httpPost.setEntity(new UrlEncodedFormEntity(nameValuePair, "UTF-8"));
        HttpResponse httpResponseGet = httpClient.execute(httpPost);
        HttpEntity resEntityGet = httpResponseGet.getEntity();
        return resEntityGet;

    }

}

将

resEntityGet

entitiy转换为字符串，如下所示

String responseString = EntityUtils.toString(resEntityGet); //response returned from your script

---

为了避免在每个类中为连接编写HTTP代码，我这样做了

创建了单独的http类，并放置了以下代码：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

import android.util.Log;


public class HttpConnect
{
    HttpClient httpClient;
    String Url;
    private static final String                 DEBUG_TAG = "TAG";


    public HttpConnect(String url) {
        this.Url = url;
        httpClient = new DefaultHttpClient();
    }

    public HttpEntity Get() throws ClientProtocolException, IOException{

        HttpGet httpGet = new HttpGet(Url);
        HttpResponse httpResponseGet = httpClient.execute(httpGet);
        HttpEntity resEntityGet = httpResponseGet.getEntity();
        return resEntityGet;
    }

    public HttpEntity Post(HashMap<String, String> c) throws ClientProtocolException, IOException{

        HttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(Url);

        // set up post data
        ArrayList<NameValuePair> nameValuePair = new ArrayList<NameValuePair>();
        Iterator<String> it = c.keySet().iterator();
        while (it.hasNext())
        {
            String key = it.next();
            nameValuePair.add(new BasicNameValuePair(key, c.get(key)));
        }

        httpPost.setEntity(new UrlEncodedFormEntity(nameValuePair, "UTF-8"));
        HttpResponse httpResponseGet = httpClient.execute(httpPost);
        HttpEntity resEntityGet = httpResponseGet.getEntity();
        return resEntityGet;

    }

}

将

resEntityGet

entitiy转换为字符串，如下所示

String responseString = EntityUtils.toString(resEntityGet); //response returned from your script

---

这也是一个很好的解决方案。但据我所知，apache http客户端不再受支持，它也是一个很好的解决方案。但据我所知，apache http客户端不再受支持。