我有个问题。我从 servlet 和 Android 开始我的冒险,我设计了一个简单的 servlet,它写着“Hello world”。现在我想在我的 Android 应用程序中收到这条消息。我的代码:
public class MyServlet extends Activity implements OnClickListener{
Button button;
TextView outputText;
public static final String URL = "http://10.0.2.2:8080/ServletExample/HelloServletExample";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewsById();
button.setOnClickListener(this);
}
private void findViewsById() {
button = (Button) findViewById(R.id.button);
outputText = (TextView) findViewById(R.id.outputTxt);
}
public void onClick(View view) {
String output = null;
HttpClient httpclient = new DefaultHttpClient();
try {
HttpResponse response = httpclient.execute(new HttpGet(URL));
HttpEntity httpEntity = response.getEntity();
output = EntityUtils.toString(httpEntity);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
//} catch (IOException e) {
// TODO Auto-generated catch block
//}
outputText.setText(output);
}
我的小服务程序:
@WebServlet("/HelloServletExample")
public class HelloServletExample extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public HelloServletExample() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
out.println("Hello World");
}
}
我不知道为什么,但我的应用程序崩溃了。我尝试注释掉一些行,结果发现问题出在这一行:
HttpEntity httpEntity = response.getEntity();
为什么?