Java中的自定义正则表达式替换

Question

我想在字符串中找到与正则表达式匹配的所有模式:no ="(\ d +)"然后用其他东西替换组中的数字.

在下面的方法中,我可以找到并替换整个匹配,但这不是我想要的.有没有办法只替换那场比赛的一部分？

private String replaceStringFromPatternSearch(String stringToSearch, String patternString, String replacementString) {
    String replacedString = null;
    Pattern stringPattern = Pattern.compile(patternString);

    Matcher stringMatcher = stringPattern.matcher(stringToSearch);
    replacedString = stringMatcher.replaceAll(replacementString);
    if (replacedString != null) {
        return replacedString;
    } else {
        return stringToSearch;
    }
}

Answer 1

Java中没有回调/ Lambda取代,但我们有其他选择

选项1:在替换功能中使用捕获缓冲区

在replaceAll,您可以从诸如捕获的文本和当时要插入的字符串等组件构建替换.这是一个例子:

String replaced = yourString.replaceAll("no=\"(\\d+)\"", 
                                         "Something $1 Something else");

在替换中,$1是捕获的数字.您不必使用它们,但正如您所看到的,您可以围绕它们构建替换字符串.

选项2(替换Lambda/Callback/Delegate Equivalent):一次构建一个匹配

在Java中,为了构建更复杂的替换,我们没有替换lambdas,但我们可以这样做:

StringBuffer resultString = new StringBuffer();
Pattern regex = Pattern.compile("no=\"(\\d+)\"");
Matcher regexMatcher = regex.matcher(subjectString);
while (regexMatcher.find()) {
        // You can vary the replacement text for each match on-the-fly
        // String computed_replacement = .... Something wild!
        regexMatcher.appendReplacement(resultString, computed_replacement );
    } 
regexMatcher.appendTail(resultString);

Answer 2

这两种方法都解决了我的问题：

示例数据：<detail type="07" time="100611" no="07040365089"detail">

我想用其他东西替换 07040365089 。no="\d" 在实际数据中出现多次。不同的模式还需要其他替代品。

private String replaceStringFromPatternSearch2(String stringToSearch, String patternString, String replacementString) {
    String replacedString = "";
    Pattern stringPattern = Pattern.compile(patternString);
    int startSearch = 0;
    Matcher stringMatcher = stringPattern.matcher(stringToSearch);
    while (stringMatcher.find(startSearch)) {
        int start = stringMatcher.start(1);
        int end = stringMatcher.end(1);
        replacedString += stringToSearch.substring(startSearch, start) + replacementString + stringToSearch.substring(end);
        startSearch = end + 1;
    }
    if (!replacedString.isEmpty()) {
        return replacedString;
    } else {
        return stringToSearch;
    }
}

private String replaceStringFromPatternSearch(String stringToSearch, String patternString, String replacementString) {
    String replacedString = "";
    Pattern stringPattern = Pattern.compile(patternString);
    int startSearch = 0;
    Matcher stringMatcher = stringPattern.matcher(stringToSearch);
    StringBuffer sb = new StringBuffer();
    while (stringMatcher.find()) {
        String wholeGroup = stringMatcher.group(0);
        replacedString = wholeGroup.replace(stringMatcher.group(1), replacementString);
        stringMatcher.appendReplacement(sb, replacedString);
    }
    stringMatcher.appendTail(sb);
    if (sb.length() > 0) {
        return sb.toString();
    } else {
        return stringToSearch;
    }
}