Question

想要从匹配特定模式的字符串返回提取的值。例如：我想从String s =“abc@hotmail.com”

中提取“hotmail”

import java.util.*;
import java.util.regex.Pattern;
import java.util.regex.Matcher;

class regexprac{
    public static void main(String args[]){
        String x = "xyz@hotmail.com";
        String existingdomain = "hotmail";

        Pattern emailPattern = Pattern.compile("^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@"+ "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$");

        if(existingdomain.equals(emailPattern.matcher(x))){
            System.out.println("Found it");
        }else{
            System.out.println("Not found it");
        }


    }
}

Answer 1

if(existingdomain.equals(emailPattern.matcher(x))){

您正在将Matcher对象与字符串进行比较。这永远不会评估为真。请参阅Pattern.matcher()。

您需要在匹配器上调用find()和group()方法，并将返回值与字符串进行比较。

<强>更新

String x = "xyz@hotmail.com";
String y = "xyz@outlook.com";
Pattern p = Pattern.compile(".+@([^.]+)\\.");
Matcher m = p.matcher(x);
if (m.find()) {
    System.out.println("found: " + m.group(1));
}
m = p.matcher(y);
if (m.find()) {
    System.out.println("found: " + m.group(1));
}

输出：

found: hotmail
found: outlook

Answer 2

试试这个：

import java.util.*;
import java.util.regex.Pattern;
import java.util.regex.Matcher;

class regexprac{
    public static void main(String args[]){
        String x = "xyz@hotmail.com";
        String existingdomain = "hotmail";

        Pattern emailPattern = Pattern.compile("(^[A-Z0-9._%+-]+)(@)([A-Z0-9.-]+)(\\.)([A-Z]{2,6}$)", Pattern.CASE_INSENSITIVE);
        Matcher matcher = emailPattern.matcher(x);
        if(matcher.find())){
            System.out.println("Found it");
            String provider = matcher.group(2);
        }else{
            System.out.println("Not found it");
        }
    }
}

使用具有模式的正则表达式从字符串中提取值

2 个答案: