尝试发送JSON请求，获取java.lang.IllegalStateException：目标主机不能为null，或者在参数中设置

Question

我尝试按下按钮时出现此错误。

11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ java.lang.IllegalStateException: Target host must not be null, or set in parameters. scheme=null, host=null, path=172.27.123.71
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at org.apache.http.impl.client.DefaultRequestDirector.determineRoute(DefaultRequestDirector.java:591)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:293)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at applicatoin.MainActivity$1.onClick(MainActivity.java:79)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at android.view.View.performClick(View.java:4438)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at android.view.View$PerformClick.run(View.java:18422)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at android.os.Handler.handleCallback(Handler.java:733)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:95)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at android.os.Looper.loop(Looper.java:136)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5017)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:515)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
11-05 22:12:30.797  31048-31048/applicatoin W/System.err﹕ at dalvik.system.NativeStart.main(Native Method)

我正在尝试向服务器发送JSON帖子请求。 这是我的代码：

package applicatoin;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import android.view.View;
import android.view.View.OnClickListener;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;
import org.apache.http.util.EntityUtils;


public class MainActivity extends Activity  {


    Button sendIPbutton; //Button for sending IP Address
    EditText mEdit; //Get info from what user enters in form
    //TextView mText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        /*get reference to views*/
        sendIPbutton = (Button) findViewById(R.id.sendIP);
        mEdit = (EditText) findViewById(R.id.enterIP);

        /*add click listener to Button "sendIPbutton"*/
        sendIPbutton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View arg0) {
                //Add JSON Logic here

                String ip = (mEdit).getText().toString();
                String json = "{\"lights\": [{\"lightId\": 1, \"red\":242,\"green\":116,\"blue\":12, \"intensity\": 0.5}],\"propagate\": true}";


                HttpClient httpClient = new DefaultHttpClient();
                HttpContext httpContext = new BasicHttpContext();
                HttpPost httpPost = new HttpPost(ip);

                try {

                    StringEntity se = new StringEntity(json);
                    httpPost.setEntity(se);
                    httpPost.setHeader("Accept", "ms3/json");
                    httpPost.setHeader("Content-type", "ms3/json");

                    HttpResponse response = httpClient.execute(httpPost, httpContext);
                    HttpEntity entity = response.getEntity();

                    String jsonString = EntityUtils.toString(entity);


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


                mEdit = (EditText)findViewById(R.id.enterIP); //get text from form?
            }
        });
      //  addListenerOnButton(); //Added for button to Send IP Address
    }

    public void sendJSONTest(View view){
        switch (view.getId()){
            case R.id.sendIP:
                String ip = (mEdit).getText().toString();
                String json = "{\"lights\": [{\"lightId\": 1, \"red\":242,\"green\":116,\"blue\":12, \"intensity\": 0.5}],\"propagate\": true}";


                HttpClient httpClient = new DefaultHttpClient();
                HttpContext httpContext = new BasicHttpContext();
                HttpPost httpPost = new HttpPost(ip);

                try {

                    StringEntity se = new StringEntity(json);
                    httpPost.setEntity(se);
                    httpPost.setHeader("Accept", "ms3/json");
                    httpPost.setHeader("Content-type", "ms3/json");

                    HttpResponse response = httpClient.execute(httpPost, httpContext);
                    HttpEntity entity = response.getEntity();

                    String jsonString = EntityUtils.toString(entity);


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

                break;

        }
    }
    public void sendJSONTest(String ip) {
        String json = "{\"lights\": [{\"lightId\": 1, \"red\":242,\"green\":116,\"blue\":12, \"intensity\": 0.5}],\"propagate\": true}";


        HttpClient httpClient = new DefaultHttpClient();
        HttpContext httpContext = new BasicHttpContext();
        HttpPost httpPost = new HttpPost(ip);

        try {

            StringEntity se = new StringEntity(json);
            httpPost.setEntity(se);
            httpPost.setHeader("Accept", "ms3/json");
            httpPost.setHeader("Content-type", "ms3/json");

            HttpResponse response = httpClient.execute(httpPost, httpContext);
            HttpEntity entity = response.getEntity();

            String jsonString = EntityUtils.toString(entity);


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

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

我不确定错误的原因是什么。该按钮确实标识了文本字段中的文本，但是当我们尝试执行HTTPrequest时，我们会收到系统错误。 JSON的格式正确。服务器甚至没有收到请求。

Answer 1

Use Seprate classes For sending all json request i will show one single demo



package applicatoin;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import android.view.View;
import android.view.View.OnClickListener;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;
import org.apache.http.util.EntityUtils;


public class MainActivity extends Activity  {


    Button sendIPbutton; //Button for sending IP Address
    EditText mEdit; //Get info from what user enters in form
    //TextView mText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        /*get reference to views*/
        sendIPbutton = (Button) findViewById(R.id.sendIP);
        mEdit = (EditText) findViewById(R.id.enterIP);

        /*add click listener to Button "sendIPbutton"*/
        sendIPbutton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View arg0) {
                //Add JSON Logic here
new SendRequest().execute(); 



                mEdit = (EditText)findViewById(R.id.enterIP); //get text from form?
            }
        });
      //  addListenerOnButton(); //Added for button to Send IP Address
    }

}

Class SendRequest extends AsyncTask<Void, Void, Void>
{
@Override
    protected Void doInBackground(Void... params) {

 String ip = (mEdit).getText().toString();
                String json = "{\"lights\": [{\"lightId\": 1, \"red\":242,\"green\":116,\"blue\":12, \"intensity\": 0.5}],\"propagate\": true}";


                HttpClient httpClient = new DefaultHttpClient();
                HttpContext httpContext = new BasicHttpContext();
                HttpPost httpPost = new HttpPost(ip);

                try {

                    StringEntity se = new StringEntity(json);
                    httpPost.setEntity(se);
                    httpPost.setHeader("Accept", "ms3/json");
                    httpPost.setHeader("Content-type", "ms3/json");

                    HttpResponse response = httpClient.execute(httpPost, httpContext);
                    HttpEntity entity = response.getEntity();

                    String jsonString = EntityUtils.toString(entity);


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

}

}