Java Matcher lookingAt() 方法

2024 年 11 月 9 日 | 阅读 2 分钟

Matcher 类的 lookingAt() 方法用于匹配输入序列的开头。此方法与 matches() 类似，但不同之处在于 matches() 方法匹配整个文本的正则表达式。

语法

参数

无参数

返回值

如果且仅当输入序列的某个前缀匹配此匹配器的模式，则为 true

示例 1

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class MatcherlookingAtExample1 {
	public static void main(String[] args) {
		    Pattern pattern = Pattern.compile("This is", Pattern.CASE_INSENSITIVE);
	        Matcher matcher = pattern.matcher("this is java language");
	        System.out.println("lookingAt = " + matcher.lookingAt());      
	}
}

输出

lookingAt = true

示例 2

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class MatcherlookingAtExample2 {
	public static void main(String[] args) {
        String input    =
                "java programming language " +
                " Write once run anywhere";

        String regex= "java programm";
 	 Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
        Matcher matcher = pattern.matcher(input);
        // searches against the beginning of the text only
        System.out.println("lookingAt = " + matcher.lookingAt());
        //Searches against the whole text
        System.out.println("matches   = " + matcher.matches());
    }
}

输出

lookingAt = true
matches   = false

示例 3

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class MatchelookingAtExample3 {
	public static void main(String[] args) {
        String input    = "java programming language " +
                		" Write once run anywhere";

        String regex= "java programm";
        Pattern p = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
        Matcher m = p.matcher(input);
        // searches against the beginning of the text only
        System.out.println(" lookingAt = " + m.lookingAt());
        if(m.lookingAt())
        	System.out.println("  "+m.toString());      
    }
}

输出

  lookingAt = true
  java.util.regex.Matcher[pattern=java programm region=0,50 lastmatch=java programm]

下一主题Java-matcher-matches-method

Java Matcher lookingAt() 方法

语法

参数

返回值

示例 1

示例 2

示例 3

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Java Matcher lookingAt() 方法

语法

参数

返回值

示例 1

示例 2

示例 3

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