Android 3.0 访问WebService 出现 android.os.NetworkOnMainThreadException异常

以前用2.2 访问WebService没有问题，到3.0上访问出现android.os.NetworkOnMainThreadException
找了资料经过实践，解决方法是在activity类中的onCreate方法中添加strict代码，如下：
 
Java代码  收藏代码

public void onCreate() {    
     .......  
     StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()       
            .detectDiskReads()       
            .detectDiskWrites()       
            .detectNetwork()   // or .detectAll() for all detectable problems       
            .penaltyLog()       
            .build());       
     StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()       
            .detectLeakedSqlLiteObjects()    
            .penaltyLog()       
            .penaltyDeath()       
            .build());    
     ......  
}    
 

 
似乎是3.0在网络上做了更加严格的限制

package org.sword.android;


import java.util.ArrayList;
import java.util.List;


import org.apache.http.HttpResponse;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;


import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.widget.Button;


public class InternetActivity extends Activity {
   
private static final String SERVER_UTL = "http://www.webservicex.net/WeatherForecast.asmx/GetWeatherByZipCode";
private Button button;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
        .detectDiskReads()
        .detectDiskWrites()
        .detectNetwork()   // or .detectAll() for all detectable problems
        .penaltyLog()
        .build());
        StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
        .detectLeakedSqlLiteObjects()
        .detectLeakedClosableObjects()
        .penaltyLog()
        .penaltyDeath()
        .build());
        getWeather();
    }
    
    private void getWeather(){
        try {
                final String SERVER_URL = "http://webservice.webxml.com.cn/WebServices/WeatherWS.asmx/getWeather"; // 定义需要获取的内容来源地址
                HttpPost request = new HttpPost(SERVER_URL); // 根据内容来源地址创建一个Http请求
                List params = new ArrayList();
                params.add(new BasicNameValuePair("theCityCode", "长沙")); // 添加必须的参数
                params.add(new BasicNameValuePair("theUserID", "")); // 添加必须的参数
                request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8)); // 设置参数的编码
                HttpResponse httpResponse = new DefaultHttpClient().execute(request); // 发送请求并获取反馈
                // 解析返回的内容
                if (httpResponse.getStatusLine().getStatusCode() != 404)
                {
                        String result = EntityUtils.toString(httpResponse.getEntity());
                        System.out.println("result =" + result);
                }
        } catch (Exception e) {
        e.printStackTrace();
        }
}
}