java - Beanshell 模式匹配器正则表达式

Question

我有以下 JSON:

[
    {
        "": "",
        "substituted_restday": "2020-02-01",
        "original_restday": "2020-02-08",
        "id": "15d13f70-c0a852c0-3a925f13-6dca1982",
        "_UNIQUEKEY_": "15d1592a-c0a852c0-3a925f13b7c65023",
        "parentId": ""
    }, 
    {
        "": "",
        "substituted_restday": "2020-02-03",
        "original_restday": "2020-02-09",
        "id": "15d14d55-c0a852c0-3a925f13-727b70af",
        "_UNIQUEKEY_": "15d1592a-c0a852c0-3a925f13-3711a584",
        "parentId": ""
    }
]

我想从“substitute_restday”中提取“日期”，即 2020-02-01 和 2020-02-03。

我有以下代码，但结果不好:

Pattern pattern = Pattern.compile("((\"substituted_restday\":\")[0-9-]+)");
Matcher matcher = pattern.matcher(JSON);
System.out.println(matcher.find());                     
if (matcher.find()){
    System.out.println(matcher.group(0));
    System.out.println(matcher);
    System.out.println("group count:" + matcher.groupCount());
    for (int i = 0; i <= matcher.groupCount(); i++) {
        System.out.println(i + ":" + matcher.group(i));
    }
}

我可以看到“matcher.find()”是正确的。但 matcher.group 没有值(value)。请帮忙。

Answer 1

您必须循环匹配的模式，然后访问group(1):

public static void main(String[] args) {
    Pattern pattern = Pattern.compile("\"substituted_restday\": \"([0-9-]+)\"");
    Matcher matcher = pattern.matcher(JSON);
    while(matcher.find()){
        System.out.println(matcher.group(1));
    }
} 

输出将是:

2020-02-01
2020-02-03

如果您访问group(0)，输出为:

 "substituted_restday": "2020-02-01"
 "substituted_restday": "2020-02-03"

The groups are identified by the brackets

group(0): ("\"substituted_restday\": \"([0-9-]+)\"")

group(1): ([0-9-]+)