记要一些常用的函数

记录一些常用的函数

public static String convertInputStreamToString(InputStream is) {StringBuilder result = new StringBuilder();if (is != null)try {InputStreamReader inputReader = new InputStreamReader(is);BufferedReader bufReader = new BufferedReader(inputReader);String line = "";while ((line = bufReader.readLine()) != null)result.append(line);bufReader.close();inputReader.close();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}return result.toString();}

public static boolean isEmpty(String string) {    return string == null || string.length() == 0;}

public static boolean isNumeric(String strNumeric) {if (isEmpty(strNumeric))return false;String patternStr = "^[-+]?\\d+(\\.\\d+)?$";if (Pattern.matches(patternStr, strNumeric))return true;elsereturn false;}

public static float getDistance(double lat1, double lon1, double lat2, double lon2) {    int EARTH_RADIUS_KM = 6371;// if there's unavailable location (0,0), return 0if (lat1 == 0 || lon1 == 0 || lat2 == 0 || lon2 == 0)return 0;double lat1Rad = Math.toRadians(lat1);double lat2Rad = Math.toRadians(lat2);double deltaLonRad = Math.toRadians(lon2 - lon1);double km = Math.acos(Math.sin(lat1Rad) * Math.sin(lat2Rad) + Math.cos(lat1Rad)* Math.cos(lat2Rad) * Math.cos(deltaLonRad))* EARTH_RADIUS_KM;return km;}