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法律研究Java 中的 Matcher pattern() 方法，附示例
java.util.regex.Matcher 类表示执行各种匹配操作的引擎。此类没有构造函数，你可以使用类 java.util.regex.Pattern 的 matches() 方法创建/获取此类的对象。
此类 (Matcher) 的 pattern() 方法获取并返回当前 Matcher 解释的 Pattern（对象）。
示例 1
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class PatternExample {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter your date of birth (MM/DD/YYY)");
String date = sc.next();
String regex = "^(1[0-2]|0[1-9])/(3[01]|[12][0-9]|0[1-9])/[0-9]{4}$";
//Creating a pattern object
Pattern pattern = Pattern.compile(regex);
//Creating a Matcher object
Matcher matcher = pattern.matcher(date);
//Validating the date
if(matcher.matches())
System.out.println("Date is valid");
else
System.out.println("Date is not valid");
//Retrieving Pattern used
Pattern p = matcher.pattern();
System.out.println("Pattern used to match the given date: \n"+p);
}
}输出
Enter your date of birth
01/21/2019
Date is valid
Pattern used to match the given date:
^(1[0-2]|0[1-9])/(3[01]|[12][0-9]|0[1-9])/[0-9]{4}$示例 2
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class PatternExample {
public static void main(String args[]) {
//Reading String from user
System.out.println("Enter a String");
Scanner sc = new Scanner(System.in);
String input = sc.next();
//Regular expression to match word that starts with a digit
String regex = "^[0-9].*$";
//Compiling the regular expression
Pattern pattern = Pattern.compile(regex);
//Retrieving the matcher object
Matcher matcher = pattern.matcher(input);
Pattern p = matcher.pattern();
System.out.println("Pattern used to match the given input string: "+p);
//verifying whether match occurred
if(matcher.matches())
System.out.println("First character is a digit");
else
System.out.println("First character is not a digit");
}
}输出
Enter a String 2sample Pattern used to match the given input string: ^[0-9].*$ First character is a digit
更新于： 20-11-2019
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