StringUtil包下,通用replace方法
/**
* Replace all occurrences of a substring within a string with another string.
* 字元串替換
* @param inString {@code String} to examine
* @param oldPattern {@code String} to replace
* @param newPattern {@code String} to insert
* @return a {@code String} with the replacements
*/
public static String replace(String inString, String oldPattern, @Nullable String newPattern) {
if (!hasLength(inString) || !hasLength(oldPattern) || newPattern == null) {
return inString;
}
int index = inString.indexOf(oldPattern);
if (index == -1) {
// no occurrence -> can return input as-is
return inString;
}
int capacity = inString.length();
if (newPattern.length() > oldPattern.length()) {
capacity += 16;
}
StringBuilder sb = new StringBuilder(capacity);
int pos = 0; // our position in the old string
int patLen = oldPattern.length();
while (index >= 0) {
sb.append(inString.substring(pos, index));//0,oldPattern前一位
sb.append(newPattern);//oldPattern開始的地方替換成newPattern
pos = index + patLen;//這裡加完之後,是原來inString的oldPattern後一位
index = inString.indexOf(oldPattern, pos);//新的oladPattern的位置(上面已經完成替換工作了,這裡可以了解成新的一段,重複以上步驟)
}
// append any characters to the right of a match
sb.append(inString.substring(pos));//把最後的都加上去
return sb.toString();
}
非常精簡,一些面試題裡有問涉及replace的算法吧,說出這個,肯定滿分