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[英]Can I invoke the doGet method and retrieve information from a servlet?
[英]How can I catch a JSON object sent from an android app to a servlet with doGet method?
我想從用戶那里獲取用戶名,密碼和電子郵件ID,構造一個JSON對象並將其發送到Java Servlet,然后將其讀取並將其插入MySql對象。 我已經使用了這個php服務器(來源: http : //www.androidhive.info/2011/10/android-login-and-registration-screen-design/ ),但是我需要在Java Servlet的幫助下完成此操作。 早些時候,我通過如下傳遞url參數來做到這一點,並且它可以正常工作,但是現在我想將該信息用作JSON參數:
Android代碼:
try {
url = new URL("http://10.0.2.2:8080/Servlet/Servlet?param1="
+ uname + "¶m2=" + pwd + "¶m3=" + eid);
// url = new URL("http://10.0.2.2:8080/Servlet/Servlet");
HttpURLConnection urlConnection = (HttpURLConnection) url
.openConnection();
InputStream in = new BufferedInputStream(
urlConnection.getInputStream());
urlConnection.disconnect();
} catch (Exception e) {
e.printStackTrace();
}
Servlet代碼:
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
{
req.setCharacterEncoding("UTF-8");
resp.setCharacterEncoding("UTF-8");
final String uname = req.getParameter("param1");
final String pwd = req.getParameter("param2");
final String eid = req.getParameter("param3");
我看了一下(http://stackoverflow.com/questions/11074934/the-json-object-sent-from-android-application-is-null-when-i-want-to-access-him),但是聽不懂
JSON代碼如下(來源: http : //www.androidhive.info/2011/10/android-login-and-registration-screen-design/ ):
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url, List<NameValuePair> params) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
Log.e("JSON", json);
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
public JSONObject loginUser(String email, String password){
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("tag", login_tag));
params.add(new BasicNameValuePair("email", email));
params.add(new BasicNameValuePair("password", password));
JSONObject json = jsonParser.getJSONFromUrl(loginURL, params);
// return json
// Log.e("JSON", json.toString());
return json;
}
首先,您要創建一個發布請求。 通常建議從get致電該職位。
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
doPost(request, response);
}
這就是我要構建他請求的JSON對象的方法
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
HttpSession httpSession = request.getSession(false);
JSONObject jJobObject = JSONObject.fromObject(request.getParameter("data"));
JJob jJob = (JJob) JSONObject.toBean(jJobObject, JJob.class);
String strTerm = (String) httpSession.getAttribute("terminal");
Integer term = null;
try {
term = Integer.parseInt(strTerm);
}
catch(Exception e) {
//
}
jJob = PersoJobService.createJob(jJob, (Integer) httpSession.getAttribute("userId"), term );
writeResponse(JSONObject.fromObject(jJob), request, response);
}
您可以通過編寫准備好的JSONObject對象並將其序列化到servlet來使用簡單的序列化。 如果您正在從Java到Java進行通信,則序列化確實非常方便。
Map<Object, Object> data = new Hashtable<Object, Object>(0);
data.put("etc", "etc");
...
URLConnection con = url.openConnection();
con.setDoInput(true);
con.setDoOutput(true);
new ObjectOutputStream(con.getOutputStream()).writeObject(data);
並從servlet
Map<Object, Object> data = (Map<Object, Object>) new ObjectInputStream(request.getInputStream()).readObject();
您甚至可以通過此方法傳遞復雜的可序列化對象。 您可以從服務寫入對象,也可以在客戶端讀取。
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