servlet显示布尔值的响应

Question

我正在尝试在我的Android应用程序和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应用程序中接收的是布尔值。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方法

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，我做错了什么吗？我尽我所能想方设法解决这个问题。任何帮助对我都有用。

Answer 1

有一个错字在你的代码

response += (inStream.hasNextLine()); 

或许应该

response += (inStream.nextLine());