android http post 参数

package com.android.httppost;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class httppost extends Activity {
    /** Called when the activity is first created. */
 private TextView mTextView1;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        URL url = null;
        HttpURLConnection httpurlconnection = null;
        try
        {
          url = new URL("http://ddddddd...");
          InputStream stream = null;
          httpurlconnection = (HttpURLConnection) url.openConnection();
          httpurlconnection.setDoOutput(true);
          httpurlconnection.setRequestMethod("POST");
          String username="params....";

         httpurlconnection.getOutputStream().write(username.getBytes());
          httpurlconnection.getOutputStream().flush();
          httpurlconnection.getOutputStream().close();
          int code = httpurlconnection.getResponseCode();
          System.out.println("code   " + code);
          stream = httpurlconnection.getInputStream();
          String str = convertStreamToString(stream);
        }
        catch(Exception e)
        {
          e.printStackTrace();
        }
        finally
        {
          if(httpurlconnection!=null)
            httpurlconnection.disconnect();
        }
       
    }
    public String convertStreamToString(InputStream is) {  
        /* 
         * To convert the InputStream to String we use the BufferedReader.readLine() 
         * method. We iterate until the BufferedReader return null which means 
         * there's no more data to read. Each line will appended to a StringBuilder 
         * and returned as String. 
         */ 
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));  
        StringBuilder sb = new StringBuilder();  
   
        String line = null;  
        try {  
            while ((line = reader.readLine()) != null) {  
                sb.append(line + "/n");  
            }  
        } catch (IOException e) {  
            e.printStackTrace();  
        } finally {  
            try {  
                is.close();  
            } catch (IOException e) {  
                e.printStackTrace();  
            }  
        }  
   
        return sb.toString();  
    }  
}