httppost

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


public class TestHttpPost {

public static void main(String[] args) throws IOException {
//创建URL对象
URL url = new URL("http://127.0.0.1:8080/student/login.php");
//通过URL对象获取一个HttpURLConnection对象
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setRequestMethod("POST");//设置请求方式为POST
conn.setDoOutput(true);//设置允许输出数据到服务器
//设置请求头信息
conn.setRequestProperty("content-type", "application/x-www-form-urlencoded");
//获取输出流 通过输出流将POST请求提交的数据发送到服务器端
String data = "username=admin&password=admin";
//获取输出流对象 通过输出流将数据输出到服务器端
OutputStream out = conn.getOutputStream();
out.write(data.getBytes());//数据写出 输出数据的操作 必须放置在读取数据前
//获取输入流 通过该流可以获取服务器端响应信息
InputStream in = conn.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
//判断响应状态码 
if(conn.getResponseCode() == 200){
System.out.println("服务器请求处理成功,返回的响应：");
String msg = null;
while((msg=reader.readLine())!=null){
System.out.println(msg);
}
}
//断开连接
conn.disconnect();

}

}

##################################################

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
    private EditText et_username;
    private EditText et_password;

    private Button bt_show;

    String result="";

    /**post请求URL地址*/
    private static final String URL="";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        init();

        bt_show.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                //android4.0后的新的特性，网络数据请求时不能放在主线程中。
                //9、使用线程执行访问服务器，获取返回信息后通知主线程更新UI或者提示信息。
                final Handler handler = new Handler() {
                    @Override
                    public void handleMessage(Message msg) {
                        if (msg.what == 1) {
                            //8、提示读取结果
                            Toast.makeText(MainActivity.this, result, Toast.LENGTH_LONG).show();
                        }
                    }
                };
                // 启动线程来执行任务
                new Thread() {
                    public void run() {
                        //请求网络
                        loginByPost(et_username.getText().toString(), et_password.getText().toString());
                        Message m = new Message();
                        m.what = 1;
                        // 发送消息到Handler
                        handler.sendMessage(m);
                    }
                }.start();

            }
        });

    }

    private void init(){
        et_username=(EditText)findViewById(R.id.et_username);
        et_password=(EditText)findViewById(R.id.et_password);
        bt_show=(Button)findViewById(R.id.bt_login);
    }

    /**
     * 请求后台，判断登录结果。
     * @param username
     * @param password
     */
    public void loginByPost(String username, String password) {
        try {
            //1、根据地址创建URL对象(网络访问的url)
            URL url = new URL(URL);
            //2、url.openConnection()打开网络链接
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            //3、设置请求的方式
            conn.setRequestMethod("POST");
            conn.setDoInput(true);//发送POST请求必须设置允许输出
            conn.setDoOutput(true);//发送POST请求必须设置允许输入
            //4、设置请求的头
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            conn.setRequestProperty("Charset", "utf-8");
            String data = "username=" + URLEncoder.encode(username, "UTF-8")
                    + "&password=" + URLEncoder.encode(password, "UTF-8");//传递的数据
            conn.setRequestProperty("Content-Length",String.valueOf(data.getBytes().length));
            //5、获取输出流
            OutputStream os = conn.getOutputStream();
            os.write(data.getBytes());
            os.flush();


            //6、获取响应的输入流对象
            InputStreamReader is = new InputStreamReader(conn.getInputStream());
            BufferedReader bufferedReader = new BufferedReader(is);
            StringBuffer strBuffer = new StringBuffer();
            String line = null;
            //7、读取服务器返回信息
            while ((line = bufferedReader.readLine()) != null) {
                strBuffer.append(line);
            }
            result = strBuffer.toString();

            //8、关闭InputStream、关闭http连接
            is.close();
            conn.disconnect();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}