Android與服務器網站交互（一）

以獲取城市天氣信息爲例

網絡鏈接配置部分——通用

<span style="font-size:18px;">import java.io.IOException;
import java.util.concurrent.TimeoutException;

import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.util.EntityUtils;

import android.content.Context;
import android.widget.Toast;

public class HttpUtil{
	private Context context;

	public HttpUtil(Context context) {
		this.context = context;
	}
	public String getWebContent(String url) throws TimeoutException 
	{
		//創建一個http請求對象 
		HttpGet request=new HttpGet(url);
		//創建HttpParams以用來設置HTTP參數
		HttpParams httpParams=new BasicHttpParams();
		//設置連接超時或響應超時
		HttpConnectionParams.setConnectionTimeout(httpParams, 3000);//3s鏈接超時
		HttpConnectionParams.setSoTimeout(httpParams, 3000);//3s響應超時
		//創建一個網絡訪問處理對象△  
		HttpClient httpClient=new DefaultHttpClient(httpParams);
		//執行請求參數項 
		try {
			HttpResponse httpResponse=httpClient.execute(request);
			 //判斷是否請求成功 
			if(httpResponse.getStatusLine().getStatusCode()==HttpStatus.SC_OK)
			{
				return EntityUtils.toString(httpResponse.getEntity());
			}
			else
			{
				Toast.makeText(context, "網絡訪問失敗，請稍後再試", Toast.LENGTH_SHORT).show();
			}
		}
		catch (ClientProtocolException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			Toast.makeText(context, "網絡訪問異常，請稍後再試", Toast.LENGTH_SHORT).show();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			Toast.makeText(context, "網絡訪問異常，請稍後再試", Toast.LENGTH_SHORT).show();
		}	
		//釋放網絡連接資源  
		finally{
			httpClient.getConnectionManager().shutdown();
		}
		return null;
		
	}

}
</span>

通過網址獲取信息——具體情況具體分析

<span style="font-size:18px;">import java.io.UnsupportedEncodingException;
import java.util.concurrent.TimeoutException;

import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.widget.Toast;

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
		StrictMode.setThreadPolicy(policy);
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		HttpUtil httpUtil=new HttpUtil(this);
		try {
			String content = null;
			try {
				content = new String(httpUtil.getWebContent("http://www.weather.com.cn/data/sk/101030300.html").getBytes("utf-8"),"UTF-8");//同時設置string編碼
			} catch (UnsupportedEncodingException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
			try {
				JSONObject result = new JSONObject( content);
				JSONObject weatherinfo = new JSONObject(result.getString("weatherinfo"));
			    Log.e("獲取的信息", content);
				Log.e("獲取的信息", weatherinfo.getString("cityid"));
			} catch (JSONException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
		} catch (TimeoutException e) {
			// TODO Auto-generated catch block
			Toast.makeText(getApplicationContext(), "網絡鏈接超時，請檢查你的網絡", Toast.LENGTH_SHORT).show();
			e.printStackTrace();
		}
		
	}
}
</span>