Java 的 Matcher hasTransparentBounds() 方法附带示例
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,可以使用 java.util.regex.Pattern 类的 matches() 方法创建/获取此类的对象。
在正则表达式中,后向和前向构建用于匹配在其他模式中,在一些其他模式中先行或后续的特定模式。例如,如果您需要接受一个接受 5 到 12 个字符的字符串,则正则表达式为 −
"\A(?=\w{6,10}\z)";
默认情况下,匹配器区域的边界对于构建前向、后向和边界匹配不透明,即这些构建不能匹配超出门区域边界的输入文本内容 −
此类的 hasTransparentBounds() 方法验证当前匹配器是否使用透明边界,如果是,则返回 true,否则,返回 false。
示例 1
import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class HasTransparentBounds { public static void main(String[] args) { //Regular expression to accepts 6 to 10 characters String regex = "\A(?=\w{6,10}\z)"; System.out.println("Enter 5 to 12 characters: "); String input = new Scanner(System.in).next(); //Creating a pattern object Pattern pattern = Pattern.compile(regex); //Creating a Matcher object Matcher matcher = pattern.matcher(input); //Setting region to the input string matcher.region(0, 4); if(matcher.find()) { System.out.println("Match found"); } else { System.out.println("Match not found"); } boolean bool = matcher.hasTransparentBounds(); //Switching to transparent bounds if(bool) { System.out.println("Current matcher uses transparent bounds"); } else { System.out.println("Current matcher user non-transparent bound"); } } }
输出
Enter 5 to 12 characters: sampletext Match not found Current matcher user non-transparent bound
示例 2
import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class HasTransparentBounds { public static void main(String[] args) { //Regular expression to accepts 6 to 10 characters String regex = "\A(?=\w{6,10}\z)"; System.out.println("Enter 5 to 12 characters: "); String input = new Scanner(System.in).next(); //Creating a pattern object Pattern pattern = Pattern.compile(regex); //Creating a Matcher object Matcher matcher = pattern.matcher(input); //Setting region to the input string matcher.region(0, 4); matcher.useTransparentBounds(true); if(matcher.find()) { System.out.println("Match found"); } else { System.out.println("Match not found"); } boolean bool = matcher.hasTransparentBounds(); //Switching to transparent bounds if(bool) { System.out.println("Current matcher uses transparent bounds"); } else { System.out.println("Current matcher user non-transparent bound"); } } }
输出
Enter 5 to 12 characters: sampletext Match found Current matcher uses transparent bounds
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