Pattern Matcher group 简单例子正则表达式

淩亂°似流年 2022-09-24 01:24 254阅读 0赞

多次使用了Matcher匹配后的group提取需要的内容。记录一下非常简单的demo。

至于正则表达式请参考其他资料，本代码片段使用了\\d匹配数字 (\\d+)表示匹配一个或多个数字。

[https://docs.oracle.com/javase/7/docs/api/java/util/regex/Matcher.html\#groupCount()][https_docs.oracle.com_javase_7_docs_api_java_util_regex_Matcher.html_groupCount]  
public int groupCount()  
Returns the number of capturing groups in this matcher’s pattern.  
Group zero denotes the entire pattern by convention. It is not included in this count.（group 0表示这个匹配pattern的整个字符串。不包括在内）

Any non-negative integer smaller than or equal to the value returned by this method is guaranteed to be a valid group index for this matcher.

import java.util.regex.Matcher;
    import java.util.regex.Pattern;
    
    public class AbsMain { 
    
        /** * @param args */
    
        final static public String CREATED_DESC        = "Created for Step '%s' of project '%s'";
        final static public String MATCHER_PATTERN     = "Created for Step '(\\d+)' of project '(\\d+)'";
    
        public static void main(String[] args) throws IOException {
    
            String str0 = String.format(CREATED_DESC, 3, 5);
            String str1 = String.format(CREATED_DESC, 5, 78);
            String str2 = String.format(CREATED_DESC, 6, 718);
            String str3 = String.format(CREATED_DESC, 31, 6);
            String str4 = String.format(CREATED_DESC, 31, 69);
            String str5 = String.format(CREATED_DESC, 391, 62);
            String str6 = String.format(CREATED_DESC, 367, 3);
            String str7 = String.format(CREATED_DESC, 361, 50);
            String str8 = String.format(CREATED_DESC, 320, 503);
            String str9 = String.format(CREATED_DESC, 36716, 37890);
    
            Pattern pattern = Pattern.compile(MATCHER_PATTERN);
            Matcher matcher = null;
            String[] strArray = {str0, str1, str2,str3 ,str4, str5, str6, str7, str8, str9};
    
            int matchCount = 0;
            int totalCount = strArray.length;
            for (String str : strArray) {
                System.out.println("Current str:" + str);
                matcher = pattern.matcher(str);
    
                if (matcher.matches()) {
                    matchCount++;
                    int groupCount = matcher.groupCount();
                    for (int i = 0 ;i < groupCount + 1; i++) {
                        System.out.println("TotalGroup:" + groupCount +", Group:" + i+ " , Value:"+ matcher.group(i));
                    }
                }
                else {
                    System.out.println("can't match with pattern.");
                }
    
    
                System.out.println("----------------------------");
                System.out.println("");
            }
    
            System.out.println("Total StringArray count:" + totalCount + ", matched pattern count:" + matchCount);
       ｝//main
       ｝//class

运行结果：  
Current str:Created for Step ‘3’ of project ‘5’  
TotalGroup:2, Group:0 , Value:Created for Step ‘3’ of project ‘5’  
TotalGroup:2, Group:1 , Value:3

## TotalGroup:2, Group:2 , Value:5 ##

Current str:Created for Step ‘5’ of project ‘78’  
TotalGroup:2, Group:0 , Value:Created for Step ‘5’ of project ‘78’  
TotalGroup:2, Group:1 , Value:5

## TotalGroup:2, Group:2 , Value:78 ##

Current str:Created for Step ‘6’ of project ‘718’  
TotalGroup:2, Group:0 , Value:Created for Step ‘6’ of project ‘718’  
TotalGroup:2, Group:1 , Value:6

## TotalGroup:2, Group:2 , Value:718 ##

Current str:Created for Step ‘31’ of project ‘6’  
TotalGroup:2, Group:0 , Value:Created for Step ‘31’ of project ‘6’  
TotalGroup:2, Group:1 , Value:31

## TotalGroup:2, Group:2 , Value:6 ##

Current str:Created for Step ‘31’ of project ‘69’  
TotalGroup:2, Group:0 , Value:Created for Step ‘31’ of project ‘69’  
TotalGroup:2, Group:1 , Value:31

## TotalGroup:2, Group:2 , Value:69 ##

。。。  
Total StringArray count:10 matched pattern count:10

[https_docs.oracle.com_javase_7_docs_api_java_util_regex_Matcher.html_groupCount]: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Matcher.html#groupCount%28%29