String 字串擷取
阿新 • • 發佈:2018-11-03
private String DateTransfer(String validEndTime){ try { if(validEndTime.length() == 8){ validEndTime = validEndTime.substring(0, 4) + "." + validEndTime.substring(4, 6) + "." + validEndTime.substring(6, 8); } } catch (Exception e) { } return validEndTime; }
substring:
public String substring(int beginIndex, int endIndex) { if (beginIndex < 0) { throw new StringIndexOutOfBoundsException(beginIndex); } if (endIndex > value.length) { throw new StringIndexOutOfBoundsException(endIndex); } int subLen = endIndex - beginIndex; if (subLen < 0) { throw new StringIndexOutOfBoundsException(subLen); } return ((beginIndex == 0) && (endIndex == value.length)) ? this : new String(value, beginIndex, subLen); }
substring中,引數beginIndex 和endIndex
擷取字串比如前四位,要從0開始到4結束
因為subLen是endIndex-beginIndex,所以如果想要擷取前四位 一定是4-0