java字符串拼接指定内容-左右组合（left/right padding）

今天在处理ID时，又一次碰到了字符串的左右拼接问题。相信很多人都有经历。

我们还是熟悉下需求，还是那句话。需求相同才是可用的解决方案。

我们需要在某个字符串的左边填充0，总长度为10位，或者右边填充0，总长度为0，或者，前后的内容固定，中间需要填充0.

String没有left padding ,right padding的函数。。那只有自己写了。。

代码性能没有测试，但是自己感觉还行。

上代码。（英语较烂，凑合看）

/** * get left padding String with specification char for existed suffix * for example,if need left padding zero for some String, * like left padding 0 to 12,and need total length 10, * then the result will be 0000000012.  *  * @param suffix * the suffix for return String * @param fill * the fill char for String * @param totalLength * the total length need for composite String * @return */public static String getLeftPadding(String suffix,char fill,int totalLength){return getFillString("",suffix,fill,totalLength);}/** * get right padding String with specification char for existed prefix * for example,if need left padding zero for some String, * like right padding 0 to A,and need total length 10, * then the result will be A000000000.  *  * @param prefix * the prefix for return String * @param fill * the fill char for String * @param totalLength * the total length need for composite String * @return */public static String getRightPadding(String prefix,char fill,int totalLength){return getFillString(prefix,"",fill,totalLength);}/** * get char fill composite String for existed prefix or suffix * for example,if need left padding zero for some String, * like padding 0 to 12,and need total length 10, * then the result will be 0000000012. what's more, * if add a prefix for this composite String,like A,  * then then return String will be A000000012. *  * @param prefix * the prefix for return String * @param suffix * the suffix for return String * @param fill * the fill char for String * @param totalLength * the total length need for composite String * @return */public static String getFillString(String prefix,String suffix,char fill,int totalLength){int c = 0;int needLength = totalLength - (prefix.length()+suffix.length());StringBuilder sb = new StringBuilder();sb.append(prefix);while(c < needLength){sb.append(fill);c++;}sb.append(suffix);return sb.toString();}public static void main(String[] args) {System.out.println(getFillString("A","1",'0',10));System.out.println(getLeftPadding("1",'0',10));System.out.println(getRightPadding("A",'0',10));}