http 访问网络 返回json 解析json

不需要任何其他包

package com.example.json;

import java.io.IOException;

import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity {

 private Button btn1;
 private TextView txt1;
 private      String baseUrl="http://ip:8088/ship/servlet/getposinfo";
 private  String str="";
    private Handler handler=new Handler()
    {
 
  @Override
  public void handleMessage(Message msg) {
     
 //  返回的字符串 直接是个数组
  // [{"devid":"1234567800","latitude":"29.4963","longitude":"116.189","postime":"2014-06-10 12:13:00"},
     // {"devid":"1234567832","latitude":"29.4943","longitude":"1161.129","postime":"2014-06-11 12:13:00"}]
   try {
    JSONArray jsonArray = new JSONArray(String.valueOf(msg.obj));
    for (int i=0;i<jsonArray.length();i++)
    {
       JSONObject jsonObject2 = (JSONObject)jsonArray.opt(i);
        str=str+"第"+i+"个,devid:"+jsonObject2.getString("devid")+"维度:"+jsonObject2.getString("latitude")+"\n";
       txt1.setText(str);
       Log.v("zms", str);
    }
   } catch (JSONException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
   super.handleMessage(msg);
  }
     
    };
 
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  btn1=(Button)findViewById(R.id.button1);
  txt1=(TextView)findViewById(R.id.textView1);
  btn1.setOnClickListener(new OnClickListener() {
   @Override
   public void onClick(View v) {
     Log.v("zms","begin");
     /*从安卓3.0以后，就不允许在主线程中直接访问网络，必须在子线程中访问
     访问后要修改主线程的UI，需要使用handler通信*/
     accessThread mythred=new accessThread();
     mythred.start();
   }
  });
 }
 
 class   accessThread extends Thread{
 
  @Override
  public void run() {
   try{
         Log.v("zms","ready");
            HttpGet geturl=new HttpGet(baseUrl);
            DefaultHttpClient httpclient=new DefaultHttpClient();
         HttpResponse response=httpclient.execute(geturl);
          Log.v("zms","响应码"+response.getStatusLine().getStatusCode());
           if (response.getStatusLine().getStatusCode()==200)
           {
               String returnStr=EntityUtils.toString(response.getEntity(),"utf-8");
            Log.v("zms","返回值"+returnStr);
             Message age=handler.obtainMessage();
             age.obj=returnStr;
             age.sendToTarget();
           } else
           {
            Log.v("zms","访问网络返回数据失败，错误码:"+response.getStatusLine().getStatusCode());
           }
       
        }
        catch(IOException e)
        {
         e.printStackTrace();
        }
   super.run();
  }
  
 }

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

}