Java 正则表达式 : Pattern and Matcher

Question

这个问题已经有答案了:

Difference between matches() and find() in Java Regex (5 个回答)

已关闭 3 年前。

尽管在线资源计算出正则表达式与扫描仪“scnr”中的字符串匹配，但以下代码块会产生“未找到匹配项”错误。如果任何人都可以通过最少的更改提供简短的代码修复，那就太好了。

String p = "([0-9]*),([0-9]*),(r|b)";

System.out.println("regex: " + p);
Pattern pattern = Pattern.compile(p);
Matcher matcher;

String testString = scnr.next();
System.out.println("test string: " + testString);
matcher = pattern.matcher(testString);

matcher.matches();

System.out.println(matcher.group(1));
System.out.println(matcher.group(2));
System.out.println(matcher.group(3));



Output:

regex: ([0-9]*),([0-9]*),(r|b)
test string: (1,65,b)
Exception in thread "main" java.lang.IllegalStateException: No match found

Answer 1

您试图将字符串与整个模式进行匹配，但由于您有多个组，所以它不起作用。

Pattern pattern = Pattern.compile("([0-9]*),([0-9]*),([rb])");
    String testString = scnr.next();
    System.out.println("test string: " + testString);
    Matcher matcher  = pattern.matcher(testString);

    while (matcher.find()) {
        System.out.println(matcher.group(1));
        System.out.println(matcher.group(2));
        System.out.println(matcher.group(3));
    }