从Java中的字符串中提取多个日期(dd-MMM-yyyy格式) [英] Extract multiple dates (dd-MMM-yyyy format) from a string in java

问题描述

我在所有地方都进行了搜索，但是找不到具体的解决方案，文档也没有对此进行介绍.所以我想从此字符串"2019年3月1日至2019年3月31日" 中提取开始日期和结束日期.问题是我无法同时提取两个日期字符串.

我在这里找到了最接近的解决方案，但由于声誉低下，无法发表评论询问如何分别提取值: https://stackoverflow.com/a/8116229/10735227

我正在使用正则表达式模式查找出现的内容，并首先将两个出现的内容都提取到2个字符串中.
这是我尝试过的:

 模式p = Pattern.compile((\\ d {1,2}-[a-zA-Z] {3}-\\ d {4})");;匹配器m = p.matcher(str);while(m.find()){startdt = m.group(1);enddt = m.group(1);//我认为这是错误的，不知道如何解决}System.out.println("startdt:" + startdt +"enddt:" + enddt); 

输出为:

  startdt:31-Mar-2019 enddt:31-Mar-2019 

另外，我需要使用DateFormatter将该字符串转换为日期(如果需要，可以在一位数字的日期前添加结尾的0).

解决方案

您只需两次调用 find 方法就可以捕获两个日期，如果只有一个，则只能捕获第一个:

  String str ="2019年3月1日至2019年3月31日"；字符串startdt = null，enddt = null;模式p = Pattern.compile((\\ d {1,2}-[a-zA-Z] {3}-\\ d {4})");匹配器m = p.matcher(str);if(m.find()){startdt = m.group(1);if(m.find()){enddt = m.group(1);}}System.out.println("startdt:" + startdt +"enddt:" + enddt); 

请注意，这可以与 while(m.find())和 List< String 一起使用，以便提取您可以找到的每个日期./p>

I have searched everywhere for this but couldn't get a specific solution, and the documentation also didn't cover this. So I want to extract the start date and end date from this string "1-Mar-2019 to 31-Mar-2019". The problem is I'm not able to extract both the date strings.

I found the closest solution here but couldn't post a comment asking how to extract values individually due to low reputation: https://stackoverflow.com/a/8116229/10735227

I'm using a regex pattern to look for the occurrences and to extract both occurrences to 2 strings first.
Here's what I tried:

Pattern p = Pattern.compile("(\\d{1,2}-[a-zA-Z]{3}-\\d{4})");  
Matcher m = p.matcher(str);
while(m.find())
{
    startdt = m.group(1); 
    enddt = m.group(1);   //I think this is wrong, don't know how to fix it
}
System.out.println("startdt: "+startdt+" enddt: "+enddt);

Output is:

startdt: 31-Mar-2019 enddt: 31-Mar-2019

Additionally I need to use DateFormatter to convert the string to date (adding the trailing 0 before single digit date if required).

解决方案

You can catch both dates simply calling the find method twice, if you only have one, this would only capture the first one :

String str = "1-Mar-2019 to 31-Mar-2019";

String startdt = null, enddt = null;

Pattern p = Pattern.compile("(\\d{1,2}-[a-zA-Z]{3}-\\d{4})");  
Matcher m = p.matcher(str);
if(m.find()) {
    startdt = m.group(1); 
    if(m.find()) {
       enddt = m.group(1);
    }
}   
System.out.println("startdt: "+startdt+" enddt: "+enddt);

Note that this could be used with a while(m.find()) and a List<String to be able to extract every date your could find.

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