Matcher lookingAt() 方法在 Java 中的示例
java.util.regex.Matcher 类表示执行各种匹配操作的引擎。该类没有构造函数,你可以使用 java.util.regex.Pattern 类的 matches() 方法创建/获取该类的一个对象。
Matcher 类的 lookingAt() 方法从区域开头开始使用模式匹配给定的输入文本。如果匹配,此方法将返回 true,否则返回 false。与 matches() 方法不同,此方法不需要整个区域中的匹配才能返回 true。
示例 1
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Test {
public static void main(String[] args) {
String regex = "(.*)(\d+)(.*)";
String input = "This is a sample Text, 1234, with numbers in between. "
+ "\n This is the second line in the text "
+ "\n This is third line in the text";
//Creating a pattern object
Pattern pattern = Pattern.compile(regex);
//Creating a Matcher object
Matcher matcher = pattern.matcher(input);
//checking for the match
if(matcher.lookingAt()) {
System.out.println("Match found");
} else {
System.out.println("Match not found");
}
}
}输出
Match found
示例 2
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class LookingAtExample {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter String1: ");
String input1 = sc.nextLine();
System.out.println("Enter String2: ");
String input2 = sc.nextLine();
System.out.println("Enter String3: ");
String input3 = sc.nextLine();
String input = input1+"\n"+input2+"\n"+input3;
System.out.println(input);
//Regular expression to match a word that contain digits
String regex = ".*\d+.*";
//Compiling the regular expression
Pattern pattern = Pattern.compile(regex);
//Retrieving the matcher object
Matcher matcher = pattern.matcher(input);
//verifying whether match occurred
boolean bool = matcher.lookingAt();
if(bool) {
System.out.println("Given input contains digit");
} else {
System.out.println("Given input does not contain any digit");
}
}
}输出
Enter String1: sample text2 Enter String2: data Enter String3: sample sample text2 data sample Given input contains digit
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