java常用方法集合
1.获取当前日期
// 获取当前日期 public Date getDate(int num) { Calendar cal = new GregorianCalendar(); cal.setTime(new Date()); cal.add(Calendar.DAY_OF_MONTH, num); return cal.getTime(); }
2.转换特殊字符,将json串转换为JS能直接识别的json
/** * 转换特殊字符,将json串转换为JS能直接识别的json * * @param oldJson * @return * @see [相关类/方法](可选) * @since [产品 /模块版本](可选) */ public static String getJsonForJS(String oldJson) { String newJson = oldJson; newJson = newJson.replaceAll("\\\\", "\\\\\\\\"); newJson = newJson.replaceAll("\\'", "\\\\'"); newJson = newJson.replaceAll("\\\"", "\\\\\""); return newJson; }
3.根据图片url获取图片的base64编码
public static String getBase64ByUrl(String urlPath){ ByteArrayOutputStream data = new ByteArrayOutputStream(); try { URL url = new URL(urlPath); byte[] by = new byte[1024]; URLConnection urlConnection = url.openConnection(); HttpURLConnection httpURLConnection = (HttpURLConnection) urlConnection; httpURLConnection.setConnectTimeout(1000*5); httpURLConnection.connect(); InputStream inputStream = httpURLConnection.getInputStream(); int len = -1; while ( (len = inputStream.read(by)) !=-1){ data.write(by,0,len); } inputStream.close(); } catch (Exception e) { logger.error("获取图片base64出错:" + e + "图片url为:" + urlPath); } return Base64.getMimeEncoder().encodeToString(data.toByteArray()); }