Http之客户端请求服务器，服务器响应客户端。通过Handler在主线程中读取数据

Http协议

客户端请求服务器，服务器响应客户端

步骤

1、生成代表客户端的HttpClient对象

2、生成代表请求的HttpGet对象

3、发送请求，获得 服务器返回的HttpResponse对象

4、判断响应状态是否正常

5、获得相应对象中的数据

/**
* 子线程Http访问服务器，取得返回的数据
* 通过Handler，主线程读取数据
*/
public class HttpActivity extends Activity {
private Button button;
private Handler handler;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_http);
button = (Button) findViewById(R.id.button);
button.setOnClickListener(new MyOnclick());
handler = new MyHandler();
}

class MyOnclick implements View.OnClickListener {

@Override
public void onClick(View v) {
//主线程当中不许访问网络
WorkThread workThread = new WorkThread();
workThread.start();
}
}

class WorkThread extends Thread {

@Override
public void run() {
//生成代表客户端的HttpClient对象
HttpClient httpClient = new DefaultHttpClient();
//生成代表请求的HttpGet对象
HttpGet httpGet = new HttpGet("http://www.marschen.com/data1.html");
try {
//发送请求，获得 服务器返回的HttpResponse对象
HttpResponse httpResponse = httpClient.execute(httpGet);
int code = httpResponse.getStatusLine().getStatusCode();
//code等于200，说明响应状态正常
if (code == 200) {
//获得相应对象中的数据
HttpEntity httpEntity = httpResponse.getEntity();
InputStream inputStream = httpEntity.getContent();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String s = bufferedReader.readLine();
//将读出的服务器数据放到message的对象中去
//使用sendMessage()发送数据
Message message = new Message();
message.obj = s;
handler.sendMessage(message);

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

class MyHandler extends Handler {

@Override
public void handleMessage(Message msg) {
//将msg中的对象读取出来
String s = (String) msg.obj;
Toast.makeText(HttpActivity.this, "输出的数据为" + s, Toast.LENGTH_SHORT).show();
}
}
}