Java字符串replace()，replaceFirst()和replaceAll()方法

2024-05-02 04:31:05 378

该`replace()`方法

String类的replace()方法接受两个String值-

一个表示要替换的String（子字符串）部分。

另一个代表需要替换指定子字符串的字符串。

使用此方法，您可以替换java中字符串的一部分。

示例

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class ReplaceExample {
   public static void main(String args[]) throws FileNotFoundException {
      String filePath = "D://input.txt";
      Scanner sc = new Scanner(new File(filePath));
      StringBuffer sb = new StringBuffer();
      String input;
      while (sc.hasNextLine()) {
         input = sc.nextLine();
         sb.append(input);
      }
      String contents = sb.toString();
      System.out.println("Contents of the file: \n"+contents);
      System.out.println(" ");
      //用所需的单词替换单词
      contents = contents.replace("Nhooo", "TP");
      System.out.println("Contents of the file after replacing the desired word: \n"+contents);
   }
}

输出结果

Contents of the file:
Hello how are you welcome to Nhooo. At Nhooo provide hundreds of technical tutorials for free.

Contents of the file after replacing the desired word:
Hello how are you welcome to TP. At TP provide hundreds of technical tutorials for free.

此方法的另一种变体还接受两个字符，分别代表现有字符和一个字符（以相同顺序），并在整个字符串中用新字符替换旧字符。

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class ReplaceExample {
   public static void main(String args[]) throws FileNotFoundException {
      String filePath = "D://input.txt";
      Scanner sc = new Scanner(new File(filePath));
      StringBuffer sb = new StringBuffer();
      String input;
      while (sc.hasNextLine()) {
         input = sc.nextLine();
         sb.append(input);
      }
      String contents = sb.toString();
      System.out.println("Contents of the file: \n"+contents);
      System.out.println(" ");
      //用所需的单词替换单词
      contents = contents.replace('T', '#');
      System.out.println("Contents of the file after replacing the desired word: \n"+contents);
   }
}

输出结果

Contents of the file:
Hello how are you welcome to Nhooo. At Nhooo provide hundreds of technical tutorials for free.

Contents of the file after replacing the desired word:
Hello how are you welcome to #utorialspoint. At #utorialspoint provide hundreds of technical tutorials for free.

该`replaceAll()`方法

String类的replaceAll()方法接受两个表示正则表达式的字符串和一个替换模式/字符串，并用指定的模式/字符串替换匹配的值。

示例

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class replaceAllExample {
   public static void main(String args[]) throws FileNotFoundException {
      String filePath = "D://input.txt";
      Scanner sc = new Scanner(new File(filePath));
      StringBuffer sb = new StringBuffer();
      String input;
      while (sc.hasNextLine()) {
         input = sc.nextLine();
         sb.append(input);
      }
      String contents = sb.toString();
      System.out.println("Contents of the file: \n"+contents);
      System.out.println();
      //用所需的单词替换单词
      contents = contents.replaceAll("\\bNhooo\\b", "TP");
      System.out.println("Contents of the file after replacing the desired word: \n"+contents);
   }
}

输出结果

Contents of the file:
Hello how are you welcome to Nhooo. At Nhooo provide hundreds of technical tutorials for free.

Contents of the file after replacing the desired word:
Hello how are you welcome to TP. At TP provide hundreds of technical tutorials for free.

该`replaceFirst()`方法

String类（也可以是replace类）的replaceFirst()方法接受两个表示正则表达式的字符串和一个替换字符串，然后用替换字符串替换第一个匹配项。

示例

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class ReplaceExample {
   public static void main(String args[]) throws FileNotFoundException {
      String filePath = "D://input.txt";
      Scanner sc = new Scanner(new File(filePath));
      StringBuffer sb = new StringBuffer();
      String input;
      while (sc.hasNextLine()) {
         input = sc.nextLine();
         sb.append(input);
      }
      String contents = sb.toString();
      System.out.println("Contents of the file: \n"+contents);
      System.out.println(" ");
      //用所需的单词替换单词
      contents = contents.replaceFirst("Nhooo", "TP");
      System.out.println("Contents of the file after replacing the desired word: \n"+contents);
   }
}

输出结果

Contents of the file:
Hello how are you welcome to Nhooo. At Nhooo provide hundreds of technical tutorials for free.

Contents of the file after replacing the desired word:
Hello how are you welcome to TP. At Nhooo provide hundreds of technical tutorials for free.

注意-所有这些方法都区分大小写。

Java字符串replace()，replaceFirst()和replaceAll()方法

该replace()方法

示例

输出结果

输出结果

该replaceAll()方法

示例

输出结果

该replaceFirst()方法

示例

输出结果

热门推荐

随机推荐

该`replace()`方法

该`replaceAll()`方法

该`replaceFirst()`方法