【移动GIS】android中访问HTTP接口

移动GIS中，访问INTERNET是不可或缺的，无论是在线地图还是离线的，都得用到，再次，整理了一个HttpConnection通用类，省的每次用的时候都copy了

import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
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.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.util.Log;


public class HttpConnection {

	private DefaultHttpClient client;
	private InputStream stream;
	private HttpEntity entity;
	private String mUserAgent;
	
	private final static int TIMEOUT_CONNECTION=3000; //ms 
	private final static int TIMEOUT_SOCKET=8000; //ms
	
	/** Constructor. 
	 * Opens the url with an HttpURLConnection, then opens a stream on it. 
	 * @param String sUrl: url to open
	 */
	public HttpConnection(){
		stream = null;
		entity = null;
		HttpParams httpParameters = new BasicHttpParams();
		/* useful?
		HttpProtocolParams.setContentCharset(httpParameters, "UTF-8"); 
		HttpProtocolParams.setHttpElementCharset(httpParameters, "UTF-8");
		*/
		// Set the timeout in milliseconds until a connection is established.
		HttpConnectionParams.setConnectionTimeout(httpParameters, TIMEOUT_CONNECTION);
		// Set the default socket timeout (SO_TIMEOUT) 
		// in milliseconds which is the timeout for waiting for data.
		HttpConnectionParams.setSoTimeout(httpParameters, TIMEOUT_SOCKET);
		client = new DefaultHttpClient(httpParameters); 
			//TODO: created here. Reuse to do for better perfs???...
	}
	
	public void setUserAgent(String userAgent){
		mUserAgent = userAgent;
	}
	
	public void doGet(String sUrl){
		HttpGet request = new HttpGet(sUrl);
		if (mUserAgent != null)
			request.setHeader("User-Agent", mUserAgent);
		try {
			HttpResponse response = client.execute(request);
			StatusLine status = response.getStatusLine();
			if (status.getStatusCode() != 200) {
				Log.e(BonusPackHelper.LOG_TAG, "Invalid response from server: " + status.toString());
			} else {
				entity = response.getEntity();
			}
		} catch (IOException e){
			e.printStackTrace();
		}
	}
	
	public void doPost(String sUrl, List<NameValuePair> nameValuePairs) {
		HttpPost request = new HttpPost(sUrl);
		if (mUserAgent != null)
			request.setHeader("User-Agent", mUserAgent);
		try {
			request.setEntity(new UrlEncodedFormEntity(nameValuePairs));
			HttpResponse response = client.execute(request);
			StatusLine status = response.getStatusLine();
			if (status.getStatusCode() != 200) {
				Log.e(BonusPackHelper.LOG_TAG, "Invalid response from server: " + status.toString());
			} else {
				entity = response.getEntity();
			}
		} catch (ClientProtocolException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	/** 
	 * @return the opened InputStream, or null if creation failed for any reason. 
	 */
	public InputStream getStream() {
		try {
			if (entity != null)
				stream = entity.getContent();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return stream;
	}
	
	/**
	 * @return the whole content as a String, or null if creation failed for any reason. 
	 */
	public String getContentAsString(){
		try {
			if (entity != null) {
				return EntityUtils.toString(entity, "UTF-8");
					//setting the charset is important if none found in the entity. 
			} else 
				return null;
		} catch (IOException e) {
			e.printStackTrace();
			return null;
		}
	}
	
	/**
	 * Calling close once is mandatory. 
	 */
	public void close(){
		if (stream != null){
			try { 
				stream.close();
				stream = null;
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		if (entity != null){
			try {
				entity.consumeContent(); 
					//"finish". Important if we want to reuse the client object one day... 
				entity = null;
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		if (client != null){
			client.getConnectionManager().shutdown();
			client = null;
		}
	}
	
}：

  该怎么用呢？很简单了，举个例子吧

HttpConnection connection = new HttpConnection();
  connection.doGet("http://www.google.com");
  InputStream stream = connection.getStream();
  if (stream != null) {
  	//得到流之后, 就可以处理了，比如XML解析等。。。
  }