首先我们先了解下Get请求和Post请求的区别：

表单提交中get和 post方式的区别有5点：
1.get是从服务器上获取数据，post是向服务器传送数据。
2.get是把参数数据队列加到提交表单的 ACTION属性所指的URL中，值和表单内各个字段一一对应，在URL中可以看到。post是通过HTTPpost机制，将表单内各个字段与其内容放置在HTML HEADER内一起传送到ACTION属性所指的URL地址。用户看不到这个过程。
3.对于get方式，服务器端用 Request.QueryString获取变量的值，对于post方式，服务器端用Request.Form获取提交的数据。
4.get 传送的数据量较小，不能大于2KB。post传送的数据量较大，一般被默认为不受限制。但理论上，IIS4中最大量为80KB，IIS5中为100KB。
5.get安全性非常低，post安全性较高。

一、HttpClinet方式

1、HTTP GET 示例:

 1 public class TestHttpGetMethod{  
 2     public void get(){  
 3         BufferedReader in = null;  
 4         try{  
 5             HttpClient client = new DefaultHttpClient();  
 6             HttpGet request = new HttpGet();  
 7             request.setURI("http://w26.javaeye.com");  
 8             HttpResponse response = client.execute(request);   
 9             in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));     
10             StringBuffer sb = new StringBuffer("");   
11             String line = "";  
12             String NL = System.getProperty("line.separator");  
13             while((line = in.readLine()) != null){  
14                 sb.append(line + NL); 
15 
16             }  
17             in.close();  
18             String page = sb.toString();  
19             Log.i(TAG, page);  
20         }catch(Exception e){  
21             Log.e(TAG,e.toString())  
22         }finally{  
23             if(in != null){  
24                 try{  
25                     in.close();  
26                 }catch(IOException ioe){  
27                     Log.e(TAG, ioe.toString());  
28                 }  
29             }  
30         }  
31     }  
32 }

带参数的 HTTP GET:
HttpGet request = new HttpGet("http://www.baidu.com/s?wd=amos_tl"); 
client.execute(request);

2、HTTP POST 示例:

 1 public class TestHttpPostMethod{  
 2     public void post(){  
 3         BufferedReader in = null;  
 4         try{  
 5             HttpClient client = new DefaultHttpClient();  
 6             HttpPost request = new HttpPost("http://localhost/upload.jsp");   
 7             List<NameValuePair> postParams = new ArrayList<NameValuePair>();  
 8             postParams.add(new BasicNameValuePair("filename", "sex.mov"));  
 9             UrlEncodeFormEntity formEntity = new UrlEncodeFormEntity(postParams);  
10             request.setEntity(formEntity);  
11             HttpResponse response = client.execute(request);  
12             in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));     
13             StringBuffer sb = new StringBuffer("");   
14             String line = "";  
15             String NL = System.getProperty("line.separator");  
16             while((line = in.readLine()) != null){  
17                 sb.append(line + NL);  
18             }  
19             in.close();  
20             String result = sb.toString();  
21             Log.i(TAG, result );  
22         }catch(Exception e){  
23             Log.e(TAG,e.toString())  
24         }finally{  
25             if(in != null){  
26                 try{  
27                     in.close();  
28                 }catch(IOException ioe){  
29                     Log.e(TAG, ioe.toString());  
30                 }  
31             }  
32         }  
33     } 
34 }

二、HttpURLConnection 方式

 1 URL url = null;
 2 HttpURLConnection conn = null;
 3 InputStream in = null;
 4 OutputStream out = null;
 5 byte[] data ="测试字符串".getBytes();
 6 try{
 7    url =new URL("www.xxx.com/servlet");
 8    conn = (HttpURLConnection) url.openConnection();
 9 
10    //设置连接属性
11    conn.setDoOutput(true);// 使用 URL 连接进行输出
12    conn.setDoInput(true);// 使用 URL 连接进行输入
13    conn.setUseCaches(false);// 忽略缓存
14    conn.setConnectTimeout(30000);//设置连接超时时长，单位毫秒
15    conn.setRequestMethod("POST");//设置请求方式，POST or GET，注意：如果请求地址为一个servlet地址的话必须设置成POST方式
16 
17 //设置请求头
18   conn.setRequestProperty("Accept", "*/*");
19   conn.setRequestProperty("Connection", "Keep-Alive");
20   conn.setRequestProperty("Accept-Charset", "utf-8");
21   if (data != null) {
22      out = conn.getOutputStream();
23      out.write(data);
24   }
25   int code = conn.getResponseCode();
26   if(code ==200){
27      in = conn.getInputStream();// 可能造成阻塞
28      long len = conn.getContentLength();
29      byte[] bs = new byte[(int) len];//返回结果字节数组
30      int all = 0;
31   int dn = 0;
32      while ((dn = in.read(bs, all, 1)) > 0) {
33        all += dn;
34        if (all == len) {
35        break;
36        }
37      }
38   }
39 }

======================================

那么接下来让我们看看在Android平台开发中如何执行一个Post请求：

以下是代码示例：

 1 package com.jixuzou.search;
 2 import java.util.ArrayList;
 3 import java.util.List;
 4 import org.apache.http.HttpResponse;
 5 import org.apache.http.NameValuePair;
 6 import org.apache.http.client.entity.UrlEncodedFormEntity;
 7 import org.apache.http.client.methods.HttpPost;
 8 import org.apache.http.impl.client.DefaultHttpClient;
 9 import org.apache.http.message.BasicNameValuePair;
10 import org.apache.http.protocol.HTTP;
11 import org.apache.http.util.EntityUtils;
12 import android.app.Activity;
13 import android.os.Bundle;
14 import android.view.View;
15 import android.view.View.OnClickListener;
16 import android.widget.Button;
17 public class mian extends Activity {
18         /** Called when the activity is first created. */
19         private Button btnTest;
20         @Override
21         public void onCreate(Bundle savedInstanceState) {
22                 super.onCreate(savedInstanceState);
23                 setContentView(R.layout.main);
24                 btnTest = (Button) findViewById(R.id.Button01);
25                 btnTest.setOnClickListener(new OnClickListener() {
26                         @Override
27                         public void onClick(View v) {
28                                 getWeather();
29                         }
30                 });
31         }
32         private void getWeather(){
33                 try {
34                         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
35                         HttpPost request = new HttpPost(SERVER_URL); // 根据内容来源地址创建一个Http请求
36                         List params = new ArrayList();
37                         params.add(new BasicNameValuePair("theCityCode", "长沙")); // 添加必须的参数
38                         params.add(new BasicNameValuePair("theUserID", "")); // 添加必须的参数
39                         request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8)); // 设置参数的编码
40                         HttpResponse httpResponse = new DefaultHttpClient().execute(request); // 发送请求并获取反馈
41 // 解析返回的内容
42                         if (httpResponse.getStatusLine().getStatusCode() != 404)
43                         {
44                                 String result = EntityUtils.toString(httpResponse.getEntity());
45                                 System.out.println(result);
46                         }
47                 } catch (Exception e) {
48                 }
49         }
50 }