android客户端与服务端交互的三种方式

android客户端向服务器通信一般有以下选择：
 1.传统的java.net.HttpURLConnection类 
2.apache的httpClient框架（已纳入android.jar中，可直接使用）
 3.github上的开源框架async-http(基于httpClient) ---------------------------------------------------------------------------------- 下面分别记录这三种方式的使用，
传统方式：

/**
     * 以get方式向服务端发送请求，并将服务端的响应结果以字符串方式返回。如果没有响应内容则返回空字符串
     * 
     * @param url 请求的url地址
     * @param params 请求参数
     * @param charset url编码采用的码表
     * @return
     */
    public static String getDataByGet(String url,Map<string,string> params,String charset)
    {
        if(url == null)
        {
            return ;
        }
        url = url.trim();
        URL targetUrl = null;
        try
        {
            if(params == null)
            {
                targetUrl = new URL(url);
            }
            else
            {
                StringBuilder sb = new StringBuilder(url+?);
                for(Map.Entry<string,string> me : params.entrySet())
                {
//                    解决请求参数中含有中文导致乱码问题
                    sb.append(me.getKey()).append(=).append(URLEncoder.encode(me.getValue(),charset)).append(&);
                }
                sb.deleteCharAt(sb.length()-1);
                targetUrl = new URL(sb.toString());
            }
            Log.i(TAG,get:url----->+targetUrl.toString());//打印log
            HttpURLConnection conn = (HttpURLConnection) targetUrl.openConnection();
            conn.setConnectTimeout(3000);
            conn.setRequestMethod(GET);
            conn.setDoInput(true);
            int responseCode = conn.getResponseCode();
            if(responseCode == HttpURLConnection.HTTP_OK)
            {
                return stream2String(conn.getInputStream(),charset);
            }
        } catch (Exception e)
        {
            Log.i(TAG,e.getMessage());
        }
        return ;
/**
     *  以post方式向服务端发送请求，并将服务端的响应结果以字符串方式返回。如果没有响应内容则返回空字符串
     * @param url 请求的url地址
     * @param params 请求参数
     * @param charset url编码采用的码表
     * @return
     */
    public static String getDataByPost(String url,Map<string,string> params,String charset)
    {
        if(url == null)
        {
            return ;
        }
        url = url.trim();
        URL targetUrl = null;
        OutputStream out = null;
        try
        {
            targetUrl = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) targetUrl.openConnection();
            conn.setConnectTimeout(3000);
            conn.setRequestMethod(POST);
            conn.setDoInput(true);
            conn.setDoOutput(true);
             
            StringBuilder sb = new StringBuilder();
            if(params!=null && !params.isEmpty())
            {
                for(Map.Entry<string,string> me : params.entrySet())
                {
//                    对请求数据中的中文进行编码
                    sb.append(me.getKey()).append(=).append(URLEncoder.encode(me.getValue(),charset)).append(&);
                }
                sb.deleteCharAt(sb.length()-1);
            }
            byte[] data = sb.toString().getBytes();
            conn.setRequestProperty(Content-Type,application/x-www-form-urlencoded);
            conn.setRequestProperty(Content-Length, String.valueOf(data.length));
            out = conn.getOutputStream();
            out.write(data);
             
            Log.i(TAG,post:url----->+targetUrl.toString());//打印log
             
            int responseCode = conn.getResponseCode();
            if(responseCode == HttpURLConnection.HTTP_OK)
            {
                return stream2String(conn.getInputStream(),charset);
            }
        } catch (Exception e)
        {
            Log.i(TAG,e.getMessage());
        }
        return ;
    }
/**
     * 将输入流对象中的数据输出到字符串中返回
     * @param in
     * @return
     * @throws IOException
     */
    private static String stream2String(InputStream in,String charset) throws IOException
    {
        if(in == null)
            return ;
        byte[] buffer = new byte[1024];
        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        int len = 0;
        while((len = in.read(buffer)) !=-1)
        {
            bout.write(buffer, 0, len);
        }
        String result = new String(bout.toByteArray(),charset);
        in.close();
        return result;
    }</string,string></string,string></string,string></string,string>
使用httpClient：
package cn.edu.chd.httpclientdemo.http;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
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.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.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import android.util.Log;
/**
 * @author Rowand jj
 *
 *http工具类,发送get/post请求
 */
public final class HttpUtils
{
    private static final String TAG = HttpUtils;
    private static final String CHARSET = utf-8;
    private HttpUtils(){}
    /**
     * 以get方式向指定url发送请求，将响应结果以字符串方式返回
     * @param uri
     * @return 如果没有响应数据返回null
     */
    public static String requestByGet(String url,Map<string,string> data)
    {
        if(url == null)
            return null;
//        构建默认http客户端对象
        HttpClient client = new DefaultHttpClient();
        try
        {
//            拼装url,并对中文进行编码
            StringBuilder sb = new StringBuilder(url+?);
            if(data != null)
            {
                for(Map.Entry<string,string> me : data.entrySet())
                {
                    sb.append(URLEncoder.encode(me.getKey(),CHARSET)).append(=).append(URLEncoder.encode(me.getValue(),utf-8)).append(&);
                }
                sb.deleteCharAt(sb.length()-1);
            }
            Log.i(TAG, [get]--->uri:+sb.toString());
//            创建一个get请求
            HttpGet get = new HttpGet(sb.toString());
//            执行get请求，获取http响应
            HttpResponse response = client.execute(get);
//            获取响应状态行
            StatusLine statusLine = response.getStatusLine();
            //请求成功
            if(statusLine != null && statusLine.getStatusCode() == 200)
            {
//                获取响应实体
                HttpEntity entity = response.getEntity();
                if(entity != null)
                {
                    return readInputStream(entity.getContent());
                }
            }
        } catch (Exception e)
        {
            e.printStackTrace();
        }
        return null;
    }
    /**
     * 以post方式向指定url发送请求，将响应结果以字符串方式返回
     * @param url
     * @param data 以键值对形式表示的信息
     * @return
     */
    public static String requestByPost(String url,Map<string,string> data)
    {
        if(url == null)
            return null;
        HttpClient client = new DefaultHttpClient();
        HttpPost post = new HttpPost(url);
        List<namevaluepair> params = null;
        try
        {
            Log.i(TAG, [post]--->uri:+url);
            params = new ArrayList<namevaluepair>();
            if(data != null)
            {
                for(Map.Entry<string,string> me : data.entrySet())
                {
                    params.add(new BasicNameValuePair(me.getKey(),me.getValue()));
                }
            }
//            设置请求实体
            post.setEntity(new UrlEncodedFormEntity(params,CHARSET));
//            获取响应信息
            HttpResponse response = client.execute(post);
            StatusLine statusLine = response.getStatusLine();
            if(statusLine!=null && statusLine.getStatusCode()==200)
            {
                HttpEntity entity = response.getEntity();
                if(entity!=null)
                {
                    return readInputStream(entity.getContent());
                }
            }
        } catch (Exception e)
        {
            e.printStackTrace();
        }
        return null;
    }
     
    /**
     * 将流中的数据写入字符串返回
     * @param is
     * @return
     * @throws IOException
     */
    private static String readInputStream(InputStream is) throws IOException
    {
        if(is == null)
            return null;
        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        int len = 0;
        byte[] buf = new byte[1024];
        while((len = is.read(buf))!=-1)
        {
            bout.write(buf, 0, len);
        }
        is.close();
        return new String(bout.toByteArray());
    }
    /**
     * 将流中的数据写入字符串返回,以指定的编码格式
     * 【如果服务端返回的编码不是utf-8，可以使用此方法，将返回结果以指定编码格式写入字符串】
     * @param is
     * @return
     * @throws IOException
     */
    private static String readInputStream(InputStream is,String charset) throws IOException
    {
        if(is == null)
            return null;
        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        int len = 0;
        byte[] buf = new byte[1024];
        while((len = is.read(buf))!=-1)
        {
            bout.write(buf, 0, len);
        }
        is.close();
        return new String(bout.toByteArray(),charset);
    }
}</string,string></namevaluepair></namevaluepair></string,string></string,string></string,string>
3.使用async-http框架，这个如果使用的话需要导入框架的jar包或者把源码拷到工程下： 这个框架的好处是每次请求会开辟子线程，不会抛networkonmainthread异常，另外处理器类继承了Handler类，所以可以在里面更改UI。 注：这里使用的是最新的1.4.4版。 ·
?

/**
     * 使用异步http框架发送get请求
     * @param path get路径，中文参数需要编码（URLEncoder.encode）
     */
    public void doGet(String path)
    {
        AsyncHttpClient httpClient = new AsyncHttpClient();
        httpClient.get(path, new AsyncHttpResponseHandler(){
            @Override
            public void onSuccess(int statusCode, Header[] headers, byte[] responseBody)
            {
                if(statusCode == 200)
                {
                    try
                    {
//                        此处应该根据服务端的编码格式进行编码，否则会乱码
                        tv_show.setText(new String(responseBody,utf-8));
                    } catch (UnsupportedEncodingException e)
                    {
                        e.printStackTrace();
                    }
                }
            }
        });
    }
    /**
     * 使用异步http框架发送get请求
     * @param path 
     */
    public void doPost(String path)
    {
        AsyncHttpClient httpClient = new AsyncHttpClient();
        RequestParams params = new RequestParams();
        params.put(paper,中文);//value可以是流、文件、对象等其他类型,很强大!!
        httpClient.post(path, params, new AsyncHttpResponseHandler(){
            @Override
            public void onSuccess(int statusCode, Header[] headers, byte[] responseBody)
            {
                if(statusCode == 200)
                {
                    tv_show.setText(new String(responseBody));
                }
            }
        });
    }
上面那个tv_show是一个TextView控件。