Question

我试图在Android App和Java Servlet之间创建一个简单的Web服务。我从servlet返回的响应是JSONObject，但我在Android应用程序中收到的是布尔值。给出了servlet和android的代码。

ANDROID CODE

 class ExecuteTask extends AsyncTask<Void, Void, Void> {
    String param;

    @Override
    protected Void doInBackground(Void... params) {
        try {
            param = "param1=" + URLEncoder.encode(_username, "UTF-8") + "&param2=" + URLEncoder.encode(_password, "UTF-8");

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

        URL url = null;

        try {
            url = new URL(url_login);

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

        HttpURLConnection conn = null;
        try {
            conn = (HttpURLConnection) url.openConnection();
        } catch (IOException e) {
            e.printStackTrace();
        }

        conn.setDoOutput(true);
        conn.setFixedLengthStreamingMode(param.getBytes().length);
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        PrintWriter out = null;

        try {

            out = new PrintWriter(conn.getOutputStream());
            out.print(param);
            Log.d("Checking Params", param);
            out.close();


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


        String response = "";
        Scanner inStream = null;


        // Log.d("JSON", json.toString());


        try {
            int responseCode = conn.getResponseCode();

            if(responseCode ==200){
               // conn.setDoInput(true);
                inStream = new Scanner(conn.getInputStream());
            }else{
                InputStream in = null;
                in = conn.getErrorStream();
            }

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

        while (inStream.hasNextLine()) {
            response += (inStream.hasNextLine());
            try {
                json = new JSONObject(response);
            } catch (JSONException e) {
                e.printStackTrace();
            }

            try {

                String s = json.getString("Login");
                Log.d("MSG", s);

                if (s != null) {
                    Intent intent = new Intent(LoginActivity.this, DashboardActivity.class);
                    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(intent);

                    Log.d("Msg sent", s);

                    finish();
                } else if (s.equals("fail")) {
                    Toast.makeText(context, "Unable to load the schedule", Toast.LENGTH_LONG).show();
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }


            conn.disconnect();
        }

        return null;

    }
}

RUNQUERY METHOD

    public JSONObject RunQuery(String[] params, HttpServletRequest request, HttpServletResponse response) {
    // System.out.println("The parameters are: " + params[0] + params[1] +
    // params[2]);
    String sql = "SELECT * FROM job_recommender.user where User_Name='"+ params[0] +"' AND password='"+ params[1] +"'";

    // System.out.println("Our SQL Statement is " + sql);

    JSONObject json = new JSONObject();
    // JSONArray jArray = null;

    try {
        Statement statement = connection.createStatement();
        ResultSet rs = statement.executeQuery(sql);

        if (rs.next()) {
            System.out.println("This is RS" + rs);
            JSONObject jObj = new JSONObject();
            jObj.put("username", (new String(rs.getString("User_Name"))));
            jObj.put("password", (new String(rs.getString("password"))));

            System.out.println(jObj);
            json.put("Login", jObj);
            System.out.println(json.put("Login", jObj));

        } 

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

    System.out.println("This is our JSON" + json);
    response.setContentType("Content-Type=application/json");
    response.setCharacterEncoding("charset=UTF-8");
    PrintWriter out; 
    try {
        System.out.println("response JSON" + json.toString());
        out = response.getWriter();
        out.println(json);
        //response.getWriter().write(json.toString());

    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return json;
}

SERVLET

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub

    //response.setContentType("text/html");

    Enumeration paramNames = request.getParameterNames();
    //System.out.println(paramNames);
    String params[] = new String[2];
    int i = 0;
    while (paramNames.hasMoreElements()) {
        String paramName = (String) paramNames.nextElement();
        System.out.println("Checking ParamNames" + paramName);

        String[] paramValues = request.getParameterValues(paramName);
        params[i] = paramValues[0];


        ulogin.setUsername(params[0]);
        ulogin.setPassword(params[1]);

        // System.out.println(params[i]);
        i++;

}
    String name = ulogin.getUsername();
    String password = ulogin.getPassword();

    System.out.println("username" + name + "password" + password);

    WebServiceDAO wdao = new WebServiceDAO(getServletContext());
    wdao.RunQuery(params, request, response);

    response.getWriter().append("Served at: ").append(request.getContextPath());


}

谁能告诉我我在这里做错了什么？我已经尝试过各种方法来解决这个问题。任何帮助对我都有用。

Answer 1

您的代码中存在拼写错误

response += (inStream.hasNextLine());

应该是

response += (inStream.nextLine());

来自servlet的响应显示布尔值

1 个答案: