用HttpClient来提交或者获取server端的数据，但是Android自带的API还是有点不好用，所以自己根据自己的需要就做了一个包装，如下：

HttpConnectionUtil类是一个工具类，其中提供了同步和异步方法，并且目前是支持http的Get和Post方法。

import java.io.BufferedReader;    
import java.io.IOException;    
import java.io.InputStreamReader;    
import java.io.UnsupportedEncodingException;    
import java.net.URLEncoder;    
import java.util.ArrayList;    
import java.util.List;    
import java.util.Map;    
import org.apache.http.HttpResponse;    
import org.apache.http.HttpStatus;    
import org.apache.http.NameValuePair;    
import org.apache.http.client.ClientProtocolException;    
import org.apache.http.client.HttpClient;    
import org.apache.http.client.entity.UrlEncodedFormEntity;    
import org.apache.http.client.methods.HttpGet;    
import org.apache.http.client.methods.HttpPost;    
import org.apache.http.client.methods.HttpUriRequest;    
import org.apache.http.impl.client.DefaultHttpClient;    
import org.apache.http.message.BasicNameValuePair; 

import android.os.Handler;
import android.util.Log;
public class HttpConnectionUtil {    
    public static enum HttpMethod {GET, POST}    
        
    public void asyncConnect(final String url, final HttpMethod method, final HttpConnectionCallback callback) {    
        asyncConnect(url, null, method, callback);    
    }    
        
    public void syncConnect(final String url, final HttpMethod method, final HttpConnectionCallback callback) {    
        syncConnect(url, null, method, callback);    
    }    
        
    public void asyncConnect(final String url, final Map<String, String> params,     
            final HttpMethod method, final HttpConnectionCallback callback) {    
        Handler handler = new Handler();    
        Runnable runnable = new Runnable() {    
            public void run() {    
                syncConnect(url, params, method, callback);    
            }    
        };    
        handler.post(runnable);    
    }    
        
    public void syncConnect(final String url, final Map<String, String> params,     
            final HttpMethod method, final HttpConnectionCallback callback) {    
        String json = null;    
        BufferedReader reader = null;    
            
        try {    
            HttpClient client = new DefaultHttpClient();    
            HttpUriRequest request = getRequest(url, params, method);    
            HttpResponse response = client.execute(request);    
            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {    
                reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));    
                StringBuilder sb = new StringBuilder();    
                for (String s = reader.readLine(); s != null; s = reader.readLine()) {    
                    sb.append(s);    
                }    
                json = sb.toString();    
            }    
        } catch (ClientProtocolException e) {    
            Log.e("HttpConnectionUtil", e.getMessage(), e);    
        } catch (IOException e) {    
            Log.e("HttpConnectionUtil", e.getMessage(), e);    
        } finally {    
            try {    
                if (reader != null) {    
                    reader.close();    
                }    
            } catch (IOException e) {    
                // ignore me    
            }    
        }
        if(callback!= null){
        	callback.execute(json); 
        }
           
    }    
    private HttpUriRequest getRequest(String url, Map<String, String> params, HttpMethod method) throws UnsupportedEncodingException {    
        if (method.equals(HttpMethod.POST)) {    
            List<NameValuePair> listParams = new ArrayList<NameValuePair>();    
            if (params != null) {    
                for (String name : params.keySet()) {