Java中的 Matcher replaceAll( 函数 ) 方法及示例

Matcher 类的replaceAll( 函数)方法表现为追加和替换方法。此方法将匹配器中匹配的模式的所有实例替换为参数中传递的函数。
句法：

public String replaceAll(
        Function replacerFunction)

参数：这个方法接受一个参数replacerFunction ，它是定义匹配器替换的函数。
返回值：该方法返回一个字符串，其目标字符串是通过替换字符串构造的。
异常：此方法引发以下异常：

• NullPointerException : 如果替换函数为空
• ConcurrentModificationException : 如果检测到替换函数修改了这个匹配器的状态

下面的示例说明了 Matcher.replaceAll() 方法：
示例 1：

Java

// Java code to illustrate replaceAll() 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 = "Geeks";
        StringBuilder builder
            = new StringBuilder();
 
        // Replace every matched pattern
        // with the target String
        // using replaceAll() method
        System.out.println("After Replacement: "
                           + matcher
                                 .replaceAll(
                                     x -> x.group().toUpperCase()));
    }
}

输出：

Before Replacement: GeeksForGeeks Geeks for For Geeks Geek
After Replacement: GEEKSForGEEKS GEEKS for For GEEKS Geek

示例 2：

Java

// Java code to illustrate replaceAll() 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
            = "GFGFGFGFGFGFGFGFGFG 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 = "(GFG)";
        StringBuilder builder
            = new StringBuilder();
 
        // Replace every matched pattern
        // with the target String
        // using replaceAll() method
        System.out.println("After Replacement: "
                           + matcher
                                 .replaceAll(
                                     x -> x.group().toLowerCase()));
    }
}

输出：

Before Replacement: GFGFGFGFGFGFGFGFGFG FGF GFG GFG FGF
After Replacement: GfgfGfgfGfgfGfgfGFG fgf GFG GFG fgf

参考： https://docs.oracle.com/javase/9/docs/api/ Java/util/regex/Matcher.html#replaceAll-java.util。函数。函数-