Java 替换字符串右侧出现的第一个子串方式

public class StringReplaceLast {
    public static String replaceLast(String src, String olds, String news){
        /* 实现一个尾部替换方法 */
        System.out.println(src);
        StringBuffer sbsrc = new StringBuffer(src);
        int lenolds = olds.length();
        int tail = src.lastIndexOf(olds);
        sbsrc = sbsrc.replace(tail,tail+lenolds, news);
        src = sbsrc.toString();
        return src;
    }
    public static void main(String[] args) {
        System.out.println(replaceLast("goodJava,I love it, very good,Truly.", "good", "yes" ));
    }
}

stringbuilder.Replace("1","a",stringbuilder.indexOf("1"),1)