替换字符串中字符的上次出现次数

Question

我有这样的字符串

"Position, fix, dial"

我想用转义双引号(\")替换最后一个双引号(")

字符串的结果是

"Position, fix, dial\"

我怎样才能做到这一点.我知道替换第一次出现的字符串.但不知道如何替换最后一次出现的字符串

Answer 1

这应该工作:

String replaceLast(String string, String substring, String replacement)
{
  int index = string.lastIndexOf(substring);
  if (index == -1)
    return string;
  return string.substring(0, index) + replacement
          + string.substring(index+substring.length());
}

这个:

System.out.println(replaceLast("\"Position, fix, dial\"", "\"", "\\\""));

打印:

"Position, fix, dial\"

试验.

Answer 2

String str = "\"Position, fix, dial\"";
int ind = str.lastIndexOf("\"");
if( ind>=0 )
    str = new StringBuilder(str).replace(ind, ind+1,"\\\"").toString();
System.out.println(str);