在java中打印正则表达式匹配

Question

所以我有一个IP地址作为字符串。 我有这个正则表达式(\d{1-3})\.(\d{1-3})\.(\d{1-3})\.(\d{1-3}) 如何打印匹配的组？

谢谢！

Answer 1

import java.util.regex.*;
try {
    Pattern regex = Pattern.compile("(\\d\\{1-3\\})\\.(\\d\\{1-3\\})\\.(\\d\\{1-3\\})\\.(\\d\\{1-3\\})");
    Matcher regexMatcher = regex.matcher(subjectString);
    while (regexMatcher.find()) {
        for (int i = 1; i <= regexMatcher.groupCount(); i++) {
            // matched text: regexMatcher.group(i)
            // match start: regexMatcher.start(i)
            // match end: regexMatcher.end(i)
        }
    } 
} catch (PatternSyntaxException ex) {
    // Syntax error in the regular expression
}

Answer 2

如果您使用模式和匹配器来执行正则表达式，那么您可以使用group(int group)方法向匹配器询问每个组

所以：

Pattern p = Pattern.compile("(\\d{1-3}).(\\d{1-3}).(\\d{1-3}).(\\d{1-3})"); 
Matcher m = p.matcher("127.0.0.1"); 
if (m.matches()) {   
  System.out.print(m.group(1));  
  // m.group(0) is the entire matched item, not the first group.
  // etc... 
}