Android开发实现查询远程服务器的工具类QueryUtils完整实例

public class QueryUtils {  private static final String TAG = "CommonUtils";  private static QueryUtils instance;  private SharedPreferences sp;  private QueryUtils(Context context){    sp = context.getSharedPreferences(Constant.CONFIG, Context.MODE_PRIVATE);  }  public static QueryUtils getInstance(Context context){    if (instance == null) {      synchronized (QueryUtils.class) {        if (instance == null) {          instance = new QueryUtils(context);        }      }    }    return instance;  }    public String getValue(String keyword, String reqType) throws Exception {    String returnValue = null;    // 使用Map封装请求参数    Map<String, String> map = new HashMap<String, String>();    map.put("reqType", reqType);    map.put("localIP", sp.getString(Constant.NETIP, ""));    if (keyword != null && !"".equals(keyword)) {      map.put("keyword", keyword);    }    String url = "http://" + sp.getString(Constant.NETURL, "") + "/ymerp/" + "ServiceDocumentServlet";    returnValue = HttpUtil.postRequest(url, map);    return returnValue;  }    public String queryServer(String keyword, String reqType, String servlet) throws Exception {    String returnValue = null;    // 使用Map封装请求参数    Map<String, String> map = new HashMap<String, String>();    map.put("reqType", reqType);    map.put("localIP", sp.getString(Constant.NETIP, ""));    if (!TextUtils.isEmpty(keyword)) {      map.put("keyword", keyword);    }    String url = "http://" + sp.getString(Constant.NETURL, "") + "/ymerp/" + servlet;    returnValue = HttpUtil.postRequest(url, map);    return returnValue;  }    @SuppressLint("SimpleDateFormat")  public static HashMap<String, Object> getMap(String jsonStr, String title, String timeStr) {    SimpleDateFormat yymmdd = new SimpleDateFormat("yyyy-MM-dd");    JSONObject jsonObject = null;    String key = null;    Object value = null;    try {      jsonObject = new JSONObject(jsonStr);      Iterator<String> it = jsonObject.keys();      HashMap<String, Object> valueMap = new HashMap<String, Object>();      while (it.hasNext()) {        key = (String) it.next();        value = jsonObject.get(key);        if (key != null && title.equals(key) && value != null) {          String valuestr = value.toString();          if (valuestr.length() > 15) {            valuestr = valuestr.substring(0, 13) + "...";            value = valuestr;          }        }        if (key != null && timeStr.equals(key)) {          try {            if (value != null) {              Date date = (Date) value;              value = yymmdd.format(date);            } else {              valueMap.put(key, "");            }          } catch (Exception e) {          }        }        if (key != null && value != null) {          valueMap.put(key, value);        }      }      return valueMap;    } catch (JSONException e) {      e.printStackTrace();    }    return null;  }}