Java中具有示例的Matching lookingAt()方法
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，可以使用类java.util.regex.Pattern的matchs()方法创建/获取此类的对象。
Matcher类的lookingAt()方法从区域的开头开始将给定的输入文本与模式匹配。如果匹配，则此方法返回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都可以返回true。
例子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");
}
}
}输出结果
Match found
例子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");
}
}
}输出结果
Enter String1: sample text2 Enter String2: data Enter String3: sample sample text2 data sample Given input contains digit