Java中的 Matcher appendTail(StringBuilder) 方法及示例

Matcher 类的appendTail(StringBuilder)方法表现为追加和替换方法。此方法读取输入字符串并将其附加到给定 StringBuilder 的尾部位置。

句法：

public StringBuilder appendTail(StringBuilder builder)

参数：此方法采用参数构建器，它是存储目标字符串的 StringBuilder。

返回值：此方法返回一个替换了目标字符串的StringBuilder 。

下面的示例说明了 Matcher.appendTail() 方法：

示例 1：

// Java code to illustrate appendTail() method
  
import java.util.regex.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // Get the regex to be checked
        String regex = "(Geeks)";
  
        // Create a pattern from regex
        Pattern pattern = Pattern.compile(regex);
  
        // Get the String to be matched
        String stringToBeMatched
            = "GeeksForGeeks Geeks for For Geeks Geek";
  
        // Create a matcher for the input String
        Matcher matcher
            = pattern.matcher(stringToBeMatched);
  
        System.out.println("Before Replacement: "
                           + stringToBeMatched);
  
        // Get the String to be replaced
        String stringToBeReplaced = "GFG";
        StringBuilder builder = new StringBuilder();
  
        // Replace every matched pattern
        // with the target String
        while (matcher.find()) {
            matcher
                .appendReplacement(builder,
                                   stringToBeReplaced);
        }
  
        // Add the replaced string at the tail
        // using the appendTail() method
        matcher.appendTail(builder);
  
        // Print the replaced matcher
        System.out.println("After Replacement: "
                           + builder.toString());
    }
}

输出：

Before Replacement: GeeksForGeeks Geeks for For Geeks Geek
After Replacement: GFGForGFG GFG for For GFG Geek

示例 2：

// Java code to illustrate appendTail() method
  
import java.util.regex.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // Get the regex to be checked
        String regex = "(FGF)";
  
        // Create a pattern from regex
        Pattern pattern
            = Pattern.compile(regex);
  
        // Get the String to be matched
        String stringToBeMatched
            = " FGF GFG GFG FGF";
  
        // Create a matcher for the input String
        Matcher matcher
            = pattern.matcher(stringToBeMatched);
  
        System.out.println("Before Replacement: "
                           + stringToBeMatched);
  
        // Get the String to be replaced
        String stringToBeReplaced = "Geeks";
        StringBuilder builder = new StringBuilder();
  
        // Replace every matched pattern
        // with the target String
        while (matcher.find()) {
            matcher
                .appendReplacement(builder,
                                   stringToBeReplaced);
        }
  
        // Add the replaced string at the tail
        // using the appendTail() method
        matcher.appendTail(builder);
  
        // Print the replaced matcher
        System.out.println("After Replacement: "
                           + builder.toString());
    }
}

输出：

Before Replacement:  FGF GFG GFG FGF
After Replacement:  Geeks GFG GFG Geeks

参考： https://docs.oracle.com/javase/9/docs/api/ Java/util/regex/Matcher.html#appendTail-java.lang.StringBuilder-