将字符串中的首字母大写

Question

我在将字符串中的第一个字母转换为Capital时遇到问题:

rackingSystem.toLowerCase(); // has capitals in every word, so first convert all to lower case
StringBuilder rackingSystemSb = new StringBuilder();
rackingSystemSb.append(rackingSystem);
rackingSystemSb.setCharAt(0, Character.toUpperCase(rackingSystemSb.charAt(0))); 
rackingSystem = rackingSystemSb.toString();

这似乎不起作用..

有什么建议？

Answer 1

尝试做:

rackingSystem = rackingSystem.toLowerCase();

代替:

rackingSystem.toLowerCase(); 

字符串是不可变的,你必须重新分配结果toLowerCase().

但是更容易(只要你的String大于长度2):

rackingSystem = rackingSystem.substring(0,1).toUpperCase() + rackingSystem.substring(1).toLowerCase();

Answer 2

StringBuilder rackingSystemSb = new StringBuilder(rackingSystem.toLowerCase());
rackingSystemSb.setCharAt(0, Character.toUpperCase(rackingSystemSb.charAt(0)));
rackingSystem = rackingSystemSb.toString();