Android REST REST服务

Question

我有一个代码，它在java项目上工作得很好，但当我在android项目上使用相同的代码时，它抛出了错误，这里是代码。(注意，我不能共享链接和参数，问题不在那里。链接是正确的。代码工作正常，我在eclipse的java项目中得到了结果，但在android项目中同样的结果失败了)

import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;
try{
        Client client=Client.create();  
        WebResource webResource2 = client.resource("some...link");

        WSDetPojo wsdetpojo = new WSDetPojo(); // some class
        wsdetpojo.parameter1("parameter1");
        wsdetpojo.parameter2("parameter2");
        wsdetpojo.parameter3("parameter3");
        wsdetpojo.parameter4("parameter4");


        ObjectMapper om=new ObjectMapper();

        ClientResponse response2 = webResource2.type("application/json")
        .post(ClientResponse.class,om.writeValueAsString(wsdetpojo)); // here is the problem <==

        System.out.println("response of sms ==> "+response2);
        if (response2.getStatus() != 201) 
        {
            throw new RuntimeException("Failed : HTTP error code : "+ response2.getStatus());

        }

        String output2 = response2.getEntity(String.class);
        System.out.println("output :\n" +output2);

    }catch(Exception ex){
        ex.printStackTrace();
    }

下面是我在android上运行它时得到的错误

java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.Object javax.ws.rs.ext.RuntimeDelegate$HeaderDelegate.fromString(java.lang.String)' on a null object reference
    at javax.ws.rs.core.MediaType.valueOf(MediaType.java:119)
    at com.sun.jersey.api.client.PartialRequestBuilder.type(PartialRequestBuilder.java:92)
    at com.sun.jersey.api.client.WebResource.type(WebResource.java:347)
    at co.example.punerto.classes.NicClient.sendData(NicClient.java:43)
    at com.example.punerto.Activity.ActivityLearnLicAppointment_Tab6$uploadFrom.doInBackground(ActivityLearnLicAppointment_Tab6.java:303)
    at com.example.punerto.Activity.ActivityLearnLicAppointment_Tab6$uploadFrom.doInBackground(ActivityLearnLicAppointment_Tab6.java:1)
    at android.os.AsyncTask$2.call(AsyncTask.java:288)
    at java.util.concurrent.FutureTask.run(FutureTask.java:237)
    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
    at java.lang.Thread.run(Thread.java:818)

请帮帮我!！已经被困了8个小时了。我也尝试了另一种选择，但没有奏效！如果你对此有其他选择，请让我知道。

Answer 1

您是否设置了所需的android权限？

 <uses-permission android:name="android.permission.INTERNET" /> 

Answer 2

实际上，当您只显示用于存储结果和发出post请求的对象时，要理解问题出在哪里太复杂了。这已经被弃用了，但在Android中仍然可以很好地工作，并且可能会对你发现错误很有用。

    try {
        //Create an HTTP client
        HttpClient client = new DefaultHttpClient();
        HttpGet get = new HttpGet("https://www...."); //your url as String
        //use HttpPost instead HttpGet if you need the post method
        //Perform the request and check the status code
        HttpResponse response = client.execute(get);
        StatusLine statusLine = response.getStatusLine();
        if (statusLine.getStatusCode() == 200) {
            HttpEntity entity = response.getEntity();
            InputStream content = entity.getContent();

            try {
                //Read the server response 
                Reader reader = new InputStreamReader(content);

                //get your data from the reader

                content.close();
            } catch (Exception ex) {
                Log.e(TAG, "Failed with: " + ex);
            }
        } else {
            Log.e(TAG, "Server responded with status code: " + statusLine.getStatusCode());
        }
    } catch (Exception ex) {
        Log.e(TAG, "Failed to send HTTP POST request due to: " + ex);
    }