从接口获取数据出现问题（新手求助~）

想做一个天气预报的功能，所以尝试着从网上的接口获取JSON数据，有一个在网上COPY下来的sycnhttp类，一个mainActivity,按照网上的教程先启动了tomcat,然后运行程序，结果出了问题，显示Toast为“未找到”，说明抛出了异常（经过我用Toast测试，在String retStr = syncHttp.httpGet(urlStr, paramsStr);这句时就无法执行了，但是可以进入try语句块，说明与后面对JSON的解析应该没什么关系。。应该就是这句话进行不下去，数据应该是没获取到），若水的教程把一个WAR包放到了tomcat的webapps文件夹中，我不会web开发什么的，小白不懂这个有用没？简单的从接口获取数据需要这个东西吗？这个天气接口，在浏览器上直接输入是有效的，但是在程序中无法获取到数据。小白求大神帮忙看看，到底是哪里出了问题呢？？跪求大神啦，这任务比较紧

sycnhttp类

package com.leo.http;



import java.io.ByteArrayOutputStream;  

import java.io.DataOutputStream;  

import java.io.FileInputStream;  

import java.io.IOException;  

import java.io.InputStream;  

import java.net.HttpURLConnection;  

import java.net.URL;  

import java.util.List;  



import org.apache.http.params.HttpConnectionParams;



import android.R.integer;

  

  

public class SyncHttp  

{  



      

    private static final int TIME_OUT = 1000 * 6; // 超时  

    private static final String METHOD_POST = "POST";  

    private static final String METHOD_GET = "GET";  

    private static final int HTTP_OK = 200;  

    private final String CHARTSET = "UTF-8"; //字符编码  

    private final int BUFFER = 1024 * 8;//缓冲区  

    public String httpGet(String urlStr, String paramsStr) throws Exception  

    {  

    	

        StringBuilder urlBuilder = new StringBuilder();  

        urlBuilder.append(urlStr);  

        if (null!=paramsStr&&!paramsStr.equals(""))  

        {  

            urlBuilder.append("?");

            urlBuilder.append(paramsStr);  

        }  

        //Log.i(Constants.TAG, urlBuilder.toString());  

        URL url = null;  

        HttpURLConnection conn = null;  

        InputStream inStream = null;  

        String response = null;  

        try  

        {  

            url = new URL(urlBuilder.toString());  

            System.out.println("");  

            //根据URL打开远程连接  

            conn = (HttpURLConnection) url.openConnection();  

            //设置参数  

            conn.setDoInput(true);  

            conn.setConnectTimeout(TIME_OUT);  

            conn.setRequestMethod(METHOD_GET);  

            conn.setRequestProperty("accept", "*/*");  

            //建立连接  

            conn.connect();  

            //接受返回码  

            int responseCode = conn.getResponseCode();  

            if (responseCode == HTTP_OK)  

            {  

                //获取输入流  

                inStream = conn.getInputStream();  

                //从输入流中获取信息  

                response = getResponse(inStream);  

            }  

            else  

            {  

                //请求失败  

                response = "返回码："+responseCode;  

            }  

        } catch (Exception e)  

        {  

            throw e;  

        }  

        finally  

        {  

            //关闭连接  

            conn.disconnect();  

        }  

        return response;  

    }  

  

    private String getResponse(InputStream inStream) throws IOException  

    {  

        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();  

        int len = -1;  

        byte[] buffer = new byte[BUFFER];//缓冲区  

        while((len=inStream.read(buffer))!=-1)  

        {  

            outputStream.write(buffer, 0, len);  

        }  

        byte[] data = outputStream.toByteArray();  

        return new String(data);  

    }  

}

mainActivity

package com.leo.http;



import org.json.JSONArray;

import org.json.JSONObject;



import android.R.string;

import android.app.Activity;

import android.app.ActionBar;

import android.app.Fragment;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.ViewGroup;

import android.widget.TextView;

import android.widget.Toast;

import android.os.Build;



public class MainActivity extends Activity 

{

    protected void onCreate(Bundle savedInstanceState) 

    {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        getweather();

    }



private void getweather()

    {

		String urlStr = "http://api.k780.com:88/";

		String paramsStr = "app=weather.future&weaid=1&appkey=10003&sign=b59bc3ef6191eb9f747dd4e83c99f2a4&format=json";

		SyncHttp syncHttp = new SyncHttp();

		

		try

		{	

			String retStr = syncHttp.httpGet(urlStr, paramsStr);//这句执行不了

			Toast.makeText(MainActivity.this,"ok", Toast.LENGTH_LONG).show();

			

			JSONObject jsonObject = new JSONObject(retStr);

			String retstring1 = jsonObject.getString("success");

			

			if (retstring1=="0")

			{

				

				JSONArray list = jsonObject.getJSONArray("results");

				

				for (int i = 0; i < 1; i++)//测试，所以只读取数组的第一项

				{

					JSONObject weatherlist = (JSONObject)list.opt(i);

					String date = weatherlist.getString("days");

					String weather = weatherlist.getString("week");

					String wind = weatherlist.getString("temperature");

					String temperature = weatherlist.getString("weather");

					Toast.makeText(MainActivity.this,"OK！", Toast.LENGTH_LONG).show();

				}

				

			}

			

			else 

			{

				//Toast.makeText(MainActivity.this, "未找到！", Toast.LENGTH_LONG).show();//被执行的不是这个toast，将其注释掉了还是会出现“未找到”

			}

			

		} 

		

		catch (Exception e)

		{

			e.printStackTrace();

			Toast.makeText(MainActivity.this, "未找到！", Toast.LENGTH_LONG).show();//在此处接收到了异常，这个toast被执行了

		}

		

	}

}

在运行程序前启动了tomcat


接口在浏览器可实现内容
http://api.k780.com:88/?app=weather.future&weaid=1&appkey=10003&sign=b59bc3ef6191eb9f747dd4e83c99f2a4&format=json

下面是LOGCAT（觉得报错的内容好像和我出现的问题没什么关联。。）